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Vegetable Gardening: Heating mat question

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HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

March 31, 2011
11:17 AM

Post #8462803

I have been thinking about purchasing a heating mat for next year. The cost made me gasp! I don't want to invest such a large sum of money in something that will last only a season or two. Could y'all let me know how long I can expect one to last?

Thanks for your help.
JoParrott
Richland, WA
(Zone 7b)

March 31, 2011
11:30 AM

Post #8462831

I have 2 heating mats-one holds one flat, and the other holds 2 flats- yes they are pricey, but I have hed mine for several years and they still work fine. It is best to have a thermostat for them, but I never did-they are high, too! You will get your moneys worth- it makes a huge difference in germination-especially with peppers & tomatoes
toni5735
Chicago, IL
(Zone 5b)

March 31, 2011
12:38 PM

Post #8462953

Hi HoneybeeNC, I bought two heating mats 5 years ago for $20.00 apiece at a Menards store here in Chicago. They are the ones that hold 1 flat. They come with a plastic tray that holds the heating mat and you can insert another tray with your seedlings on top of that. You can use the mat with the holding tray or without. The mats work great and hold up very well; mine look brand new. I can't say the same for the holding tray, it's thin plastic and the corners started to tear at the bottom. But Duck Tape can fix anything!

I don't know the going rate for mats now but as for their durability, I've used mine for going on 6 years now.

Here's a pic of the kind I got.

Toni

Thumbnail by toni5735
Click the image for an enlarged view.

weasel71
Lombard, IL
(Zone 5a)

March 31, 2011
1:48 PM

Post #8463107

Toni- I just purchased the same exact mats from my local Menard's store and they were $20 each, but that was for the mat only, no trays. I too wondered how long these things are expected to last. I was encouraged to know that your mats have lasted 6 years and still look new.

Honeybee- I checked amazon.com before I bought mine and they're all in the $20 range, pretty much. The mats that Toni and I have are the Hydrofarm brand. I could use another mat or two, so if you stumble across any that are cheaper, please let me know.

Good luck!


HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

March 31, 2011
4:47 PM

Post #8463534

Thanks for all the replies. You've given me tthe confidence I needed to purchase one.

drthor

drthor
Irving, TX
(Zone 8a)

April 5, 2011
7:08 AM

Post #8473289

I bought my 48" heating mat this year and I wish I did before.
My seedlings sprouted so much faster and they are so healthy and willing to grow on top of the mat.
I really suggest to also buy the thermostat, otherwise the mat will get too hot.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 5, 2011
7:54 AM

Post #8473397

drthor - thanks for the update. I've put a heating mat and thermostat on my Christmas wish list.
eweed
Everson, WA
(Zone 8a)

April 8, 2011
8:25 AM

Post #8480377

Honeybee I have four 48 inch ones and Drthor is correct the mats are much better with a thermostat because the way they work is they sense the ambient temp and heat it to about 20 degrees more.If you are using it in a house at 70 it will heat to 90 and thats to hot even for peppers to do well.

One way to beat the heat without a thermostat is raise the flat above the mat and let some air flow in. How far can be determined with a thermometer.Ernie

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

April 8, 2011
5:27 PM

Post #8481434

I'm going to cruise Goodwill and Salvation Army for an aluminium cookie sheet. I only have one heating pad (10"x20") and four trays of inserts. Even when I buy another pad, i wnat to spread the heat around.

I got two squares of drywall (2'x2') from Home Depot for bottom insulation, and I figure that doubles the amount of heat that goes up.

Corey
mraider3
Helena, MT

April 9, 2011
2:41 AM

Post #8482096

I have two 48" heating mats and one theromostat which I never use. I also have two heating mats from Growers Supply which I use in my garage which stays around 50 degrees. The Growers Supply heating mats do not come with a thermostat and can get pretty hot so I use a timer with these. One thing I should point out about Growers Supply is there shipping prices are exorbant in some cases. Always check first before you make your purchase. They will gouge you if you don't and they will negotiate on shipping if you don't like the price.
lukerw
Rochester, IL

April 9, 2011
8:27 AM

Post #8482611

I have found these soil heating mats to be identical to the foot heating mats often used by office workers. I bought five foot heating mats a couple years ago over the Internet from some discounter for $10 apiece, and got some shelving at Menards to put below them so they weren't touching the shelf.

The pads will heat up to around 100 degrees. Seedlings need a range from 68 to 86 depending on the plant. I have found raising the beds four inches above the mats does the job, but a thermometer is essential.
I picked up a small Air King fan with a clip to attach to a shelf that worked great for circulating the air. And used cinnamon powder to conteract the dying off fungus.

Thumbnail by lukerw
Click the image for an enlarged view.

mom2goldens
Carmel, IN
(Zone 5b)

April 9, 2011
10:57 AM

Post #8482965

I've got the same mat/tray setup from Menard's that Toni has. I've had mine for 2 years and really like it. I agree the plastic tray is a little flimsy, but so far it's holding up OK.

I also have a 2-tray Hydrofarm heat mat. My first one only lasted 2 years before it just died; I hope my new one holds up better (I'm currently starting my 2nd season with it). I don't use a thermometer, and so far it hasn't been an issue.

gardadore
Saylorsburg, PA
(Zone 6a)

April 9, 2011
6:08 PM

Post #8483714

A couple of years ago there was a co-op for the Hydrofarm Heat Mat for about $39 through Grower's Solution. I see they offer the two tray 20"x20" for $41.95 with free shipping. http://growerssolution.com/page/GS/PROD/heatmats/MT10008 The one tray mat is 9" x 19 1/2" and costs $31.95 with shipping. http://growerssolution.com/page/GS/PROD/heatmats/MT10008
The two tray one is definitely a better bargain.
One can maybe find the same mat cheaper on the Internet but then the shipping makes them more expensive. I have had my first mat for at least 6 years and the new one from Grower's Solution for 2 years. Never had a problem with either of them and don't use a thermostat. They make all the difference in germination.
I am editing to add Amazon.com (http://www.amazon.com/Hydrofarm-MT10006--19-1-2-Inch-Seedling/dp/B0001WV010/ref=sr_1_1?ie=UTF8&qid=1302398092&sr=8-1) as an even better deal since they also offer free shipping on items over $25 and offer the two tray one for $37.65 which is like getting 2 one tray mats for about $18.83 each - not bad at that rate!
Even better is the 48" x 20" for $55.79 which should accommodate 4 trays. That would be equivalent to 4 one tray mats at $13.95 each! If I didn't already have 2 2 tray mats I would opt for the largest one.

This message was edited Apr 9, 2011 9:29 PM

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 10, 2011
6:21 AM

Post #8484629

gardadore - thanks for posting the grow mat info.
mraider3
Helena, MT

April 10, 2011
2:41 PM

Post #8485516

This may or may not be relevant to the discussion here but I was reading a thread started by and engineer "Russ" who was experimenting with those seed block makers and Russ actually placed the heater inside the tray or flat which held the seed blocks. He also used a layer of sand over the bottom of these trays to even out and get the maximum benefit of the heat pad. The plastic seed flats puss the grated inserts which many of us use can lose much of the benefit of the heat mats based on their design. The flats have several dimples on the bottom and groves inside which tends to reduce the amount of transfer heat. The ambient temperatures of my germination areas are either 60 or 50F and starting hot peppers requires a different approach for me since these heat mats do not provide the warmth necessary to get good germination of the pepper seeds. I use peat pots to germinate my tomato and pepper seeds, and I place up to twenty seeds per pot. I prefer to use a flat, square ceramic dish which holds four of the 3.5 inch square peat pots for both tomato and pepper seed germination. I water these peat pots initially with warm water containing a 1:32 dilution of hydrogen peroxide to water since I use grated spent vermiculture media as my germination mix. I have found that maintaining a layer of water in the bottom of the ceramic dish also helps, even in addition to misting the surface of the peat pots three times a day. Mold or dampening off has not been a problem with the use of hydrogen peroxide, but I have a small fan available if necessary to combat these problems if they should occur. So, for what it's worth, I think these heat mats are beneficial in germinating all types of seeds.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

December 29, 2011
8:00 AM

Post #8946467

My daughter purchased a windowsill heat mat for me as a Christmas gift, so I'm going to experiment with this.

http://www.amazon.com/Hydrofarm-MT10004-Windowsill-Heat-Mat/dp/B0044U4F5I/ref=sr_1_1?s=garden&ie=UTF8&qid=1325174140&sr=1-1

My garden room's air temperature is usually in the 50's during the winter months, so if this mat heats up the soil into the 70's that should be good enough to start vegetable seeds. I'll invest in a larger mat later, if I like this trial period.

drthor

drthor
Irving, TX
(Zone 8a)

December 29, 2011
8:06 AM

Post #8946472

I am very fond of my heating mat.
I am sure you will like it. My heating mat is now set at 85 degrees for the tomatoes.
If you will buy a larger one you may consider on investing on a termostat too. The heating mat can get really really hot.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

December 29, 2011
8:14 AM

Post #8946481

drthor - do you know what your ambient air temperature is where you use the heat mat? I'm assuming from what you wrote that the thermostat prevents the mat from getting too hot.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

December 29, 2011
8:17 AM

Post #8946484

I'm using mine right now in the greenhouse to set my Elephant Ear, an Avocado tree and bottles of rain water on to keep them warmer during the winter. Works great in that situation. Come late February or March I will start my tomatoes and peppers using it. Since it stays cooler in the GH it really doesn't get too hot for the seedlings. I used it last year inside a spare bedroom with no thermometer and the seedlings just burnt up, hardly any germination.

Doug

drthor

drthor
Irving, TX
(Zone 8a)

December 29, 2011
1:31 PM

Post #8946808

HoneybeeNC
My growing shelf is in my laundry room. So it is normally at the temperature of the house.
Tomatoes, peppers, eggplants, zucchini, cucumbers and okra sure love the extra heat.
My mat is 4' long and I don't know if : bigger the mat = hotter the mat ... but I really did toast the seeds before using the thermostat ...
Definetly it is worth it a lot. My tomato seeds germinatd in 3 days !!!
gardadore
Saylorsburg, PA
(Zone 6a)

December 29, 2011
2:19 PM

Post #8946860

Sounds like Hydrofarm has come out with a new size, Honeybee. I had not seen the window sill version but it sounds very practical. I have had my two Hydrofarms for years and wouldn't be without them in the spring. I wish you all happy sowing as well as a productive NEW YEAR!!

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

December 29, 2011
2:34 PM

Post #8946882

I'm on a budget. So, last January, I sowed my seeds into potting mix that I sterilized in the microwave. It was warm to the touch when I sowed the seeds. I immediately watered them gently with WARM water. Then I quickly shoved the flats into large plastic hospital bags with the drawstrings and left just a tiny vent for some air. The bags fogged up. Then, I put them on the floor under my light shelf, in the dark, in the warmest room in my house.

They popped all at once. On the third day...in the dark...no heat mat.

Just used the free heat I had available...

Out of 212 seeds sown, 212 came up. 208 made it into healthy seedlings. 4 perished only because by the time I had potted up the 208 and looked over at the 4 remaining runts, I was weary enough to just toss them.

"Murder, she wrote..."
rjogden
Gainesville, FL
(Zone 8b)

December 29, 2011
8:09 PM

Post #8947159

Gymgirl wrote:I'm on a budget.


The simplest (and cheapest) "heating mat" I've ever used was a shelf placed above a set of fluorescent lights I was using to keep some tender plants alive through the winter. It worked fine, but you have to play with the spacing to control the heat.

-Rich
kmom246
Murfreesboro, TN
(Zone 7a)

December 29, 2011
8:22 PM

Post #8947170

I also love my heating mat. Don't recall what brand, but I got it from Home Depot 6 years ago, and it is still going strong. it holds one flat. I don't have a thermostat. It sits on a wire shelf with the flat on top of it. As soon as the toms or pepper's pop up, they get moved off the mat (only one heat mat, and too many seedlings to start). My toms & pepper germination has been near 100% since I purchased the heat mat. My laundry room, where I start seeds, gets down to 40 at night during the winter. My wire seed shelf setup gets covered with plastic and the heat mat mitigates the temps inside by a degree or two.

Have fun experimenting with your new heating mat.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

December 30, 2011
11:38 AM

Post #8947819

Thanks for all the good wishes and experiences with heating mats. I'm going to have fun experimenting.

Gymgirl - I know what you mean about being on a budget. I just finished my end-of-year tally, and there's only a little over $500 between my opening and closing balances! BUT - I'm in the "black" - YAY!
kmom246
Murfreesboro, TN
(Zone 7a)

December 30, 2011
12:29 PM

Post #8947897

In the Black is Good!

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

December 30, 2011
12:54 PM

Post #8947925

Translation: "I have enough left to go buy a heat mat -- or, two!" ^:-)^
gardadore
Saylorsburg, PA
(Zone 6a)

December 30, 2011
4:38 PM

Post #8948263

Check out the Amazon link I posted above since the costs are still low and you don't pay postage on any order over $25. The mat for one tray is $21.99. They offer the three sizes so just click on the one you are interested in to bring up the current price. That still seems to be the best price around for the Hydrofarm mats that I have found! Happy growing everyone in the New Year!! I won't begin until end of March with seeding so envy you in the south for being able to think about it now!! I'm still compiling lists and ordering seeds!

stephanietx

stephanietx
Fort Worth, TX
(Zone 8a)

January 4, 2012
6:03 AM

Post #8953981

What a timely thread! I have gift cards to Amazon. Let the shopping begin!
TLeaves
Ramona, CA
(Zone 9b)

January 4, 2012
7:55 PM

Post #8954902

The temperatures here swing 20-30 degrees a day and my seeds will not be in the house this year, so I think I should consider a thermostat.

How do the thermostats typically work? Are some heating mats sold with a built-in thermostat or is the thermostat always a separate purchase.. or ?

This message was edited Jan 4, 2012 9:02 PM
rjogden
Gainesville, FL
(Zone 8b)

January 4, 2012
9:06 PM

Post #8954972

The thermostat I bought at Amazon has a probe on the end of a wire that you place where you want the temperature measured. I believe that would be best put between the mat and the middle flat, to avoid cooking your seeds. The thermostat itself plugs into the wall and has an outlet into which the mat is plugged. There is a digital readout and controls on the front to set the temperature. Pretty simple really.
TLeaves
Ramona, CA
(Zone 9b)

January 4, 2012
9:35 PM

Post #8954986

Thanks rjogden. I was wondering how a separate thermostat would know the temperature of the mat, so the probe makes sense. The digital readout sounds nice and simple as you say. It seems like it would be even simpler if someone would just make a mat with a built-in thermostat. But I guess this way, they can sell us more products. :)
Horseshoe
Efland, NC
(Zone 7a)

January 5, 2012
8:45 AM

Post #8955251

Actually it is better to insert your probe (Rich) directly into the soil of one of your flats or pots. This way the thermostat measures the temperature of the soil, not the temperature of the mat itself. All things being equal (size of pots or flats, depth of soil, etc) having the probe in a flat or pot with that one telling the thermostat to turn off and on then all the other flats/pots will be that temperature as well.

Tleaves, they do may mats, as well as heating cables, that have built in thermostats but usually those are the ones they turn off at a preset factory given temp. Those will be ones that show "heats soil 20 degrees above ambient temperature". Ideally you'll want a minimum of 70 for most veggie seed germination; if your room is 40 degrees those mats would be hard-pressed to bring your soil temperature past 60.

Shoe

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

January 5, 2012
10:07 AM

Post #8955350

A tip I read recently suggested inserting the probe into a pot of soil that does not contain seeds so as not to disturb the roots.
Horseshoe
Efland, NC
(Zone 7a)

January 5, 2012
11:25 AM

Post #8955440

Yep, you can do that, Honeybee. The "probe pot" should be the same size as other pots or trays being used on the heat mat though so you know the soil temps in all trays are the same.
As for me, I've used probe thermostats for more years than I care to admit and have never damaged any seeds or roots, the probe is very slim and easily slides in or out of the medium.

Shoe

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 5, 2012
12:55 PM

Post #8955552

Glad your're not a Proctologist Shoe!

Doug
Horseshoe
Efland, NC
(Zone 7a)

January 5, 2012
1:13 PM

Post #8955572

Hah! *grinnin' here...
Nope, definitely not my line of work!

Hope you're warm over your way.

Shoe (who's favorite phone message was, "Shoe, the proctologist called. They found your head!") (heheh, I think someone was mad at me that day!) :>)

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 5, 2012
6:59 PM

Post #8956096

My version of that one "his head was so far up there, that I couldn't see his elbows!"

>> if your room is 40 degrees those mats would be hard-pressed to bring your soil temperature past 60.

I agree, but it helps to "keep the heat in" by putting insulation under and around the tray or pots. Drywall is good. You can keep a dome or film OVER the soil until seeds emerge, but then you have to let humidity out and fresh air in to prevent damping off.

Florescent lights won't heat the soil, but metal halide (not HID) or incandescent sure will. Beware cooking the seedlings!

Corey
Horseshoe
Efland, NC
(Zone 7a)

January 5, 2012
8:25 PM

Post #8956203

Hehehe, too funny, Corey. *grin

Ditto, what you said, about holding heat in. I keep my pots of rooting cuttings and such on a heat mat and in a plastic grocery bag with the top tied. This holds in heat very well. Opening the top from time to time to allow an air exchange and excess moisture out is necessary.

Shoe.
JoParrott
Richland, WA
(Zone 7b)

January 5, 2012
10:20 PM

Post #8956276

I have scrounged several styrofoam Grape containers from our Winco store, and plan to use them as perimeter insulation for my seed flats that will be on the heat mat. They are the perfect shape and size. I'll take photos and post tomorrow. Sure getting antsy for Spring!
cornish2175
Charleston, SC
(Zone 8b)

January 6, 2012
4:53 AM

Post #8956374

I usually have 8 flats at one time under lights- I start a lot extra of everything to gift my neightbors- I found that financially and plug space wise it was not practical to have heat mats. We had a bad cold snap and my plant room temperature dropped to around 65. I put a small electric heater in there and within hours the temp rose to about 74- and that was with running the heater on the economy setting. I have plastic domes over germinating seeds which keeps the humidity high and run the ceiling fan to circulate the air.

My tomatoes and herbs came up in 5 days and today I see the peppers and eggplant peeking thru.

This may be another solution to those who do not have heating mats.

Thumbnail by cornish2175
Click the image for an enlarged view.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 6, 2012
5:55 AM

Post #8956425

Well the double heat mat I have only draws 45 watts so It's cheaper that using an incandescent light.

Doug
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 6, 2012
6:30 AM

Post #8956467

We've used heat mats (with temp controls on the mat) for a number of years without any issues on the plants. We've used both regular and self watering flats. The flats are all in the basement. Until recently we've only put the seeds that have a higher germination temp on the heat mats. Last winter was cold and so more items went on the mats than usual. I haven't noticed any negative reaction because of the heat mats. We let the heater mats run 24/7 until the basement or outside is warm enough for the plants.

I'm not a big fan of portable electrical space heaters being left running unattended as they are a high risk in causing fires. So please make sure that anyone using them does not leave them unattended.

Horseshoe
Efland, NC
(Zone 7a)

January 6, 2012
9:29 AM

Post #8956693

Much easier on my finances to heat the soil in trays and pots than to heat a whole greenhouse. Like Susan I've never had any troubles with heat mats but there might be a small learning curve for some folks. Fortunately I LOVE thermometers and am always taking the temperature somewhere. (Heck, I even have thermometers nailed to trees out in the woods, just because!) *grin

Shoe

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 6, 2012
10:34 AM

Post #8956780

Well, my soil heating method works for me! I BROKE LAST YEAR'S GERMINATION TIME RECORD!

Two flats popped last night (Mule Team and Black Krims, 3 days), and 3 more popped overnight (Russian Rose, Momotaro, Virginia Sweets, ~ 84 hours). I sowed seeds on Monday evening, January 2, 2012. Waiting on the Perfect Purples...

They've all been shoved under the fluorescent shop lights, which are laying on top of the flats.

Last year I had 6 flats come up on a Sunday, 6 days after sowing, and all at once.



This message was edited Jan 6, 2012 12:37 PM

Thumbnail by Gymgirl
Click the image for an enlarged view.

SusanKC
Shawnee Mission, KS
(Zone 6a)

January 6, 2012
12:23 PM

Post #8956939

We seem to have a similar need to know temp affliction at our house. We have a temp sensor on the front of the house, in the backyard, on a window, and in the attic. A combination of remote and local sensors, a mobile temp sensor, and a direct link to weather.com (and a couple of others) on the cell. No tree temps yet. :-)

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 6, 2012
12:47 PM

Post #8956968

That is sooooooooooo funny! LOL!
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 6, 2012
1:06 PM

Post #8957003

The funny part is the DH's family is from VA and he's a redhead. I was wondering as I was writting the post above if he possibly related to Shoe as they have a similar interest in the temp. The DH also has his own soil temp probe. :-)

The attic temp also transmits humidity.
Horseshoe
Efland, NC
(Zone 7a)

January 6, 2012
3:45 PM

Post #8957204

Heheheheh, yey for Susan's hubby! Another temperature freak! And yes, got the soil probe's, too. And one of them, a digital, doubles as a cookin/meat thermometer so I don't overcook my chicken and steaks! :>) At one point in time local friends "worried" about me, with thermometers everywhere: old mailpouch thermometer outside the Shoffice, huge dial thermometer, on another wall, a combo thermometer/hygrometer/humidity meter elsewhere, wireless thermometers in the greenhouse, under the overhang where the tractors are parked. And of course I'm sure something is hanging in the chicken coop, too! :>)

GG, congrats on your tomatoes declaring! You're on your way now!

Shoe (wondering how cold it'll get tonight) *grin

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 7, 2012
4:12 AM

Post #8957765

OK Shoe tell us how bad you really got it. How many rain gauges do you have?????

Crackin' up in KY..
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 7, 2012
6:21 AM

Post #8957869

Sorry. Neglected to mention the numberous cooking temperature sensors the DH has. One electronic remote cooking sensor, one candy thermometer, one what temp is the fridge, one what temp is the oven, and one old style what temp is the meat.

We don't have any chicken coups or tractors so I'm sure about those. But I never thought to ask what he has at the office. And thinking about the garage I remembered the last car we bought (his choice) has a ambient temperature sensor and weather band radio.

I'm also thinking all those years of marriage and I never realized there was a temperature obsession.

DH had a number of rain gauges but they kept getting pounded by all that Kansas hail and knocked over by the local varmits (dog, cats, woodchuck, etc). I think he's given up on gauges in the yard as I can't remember any in the yard right now. However, he can get all that information locally now on the web so maybe he's just outsourcing the job.
Horseshoe
Efland, NC
(Zone 7a)

January 7, 2012
8:51 AM

Post #8958049

"just outsourcing the job". Great idea, Susan!

I'll see your last post and raise ya...

...One oven thermometer which also travels out to the smoker grill from time to time; two weather radios, one with a built-in digital thermometer plus a pull-out compass on top; a plastic chicken weathervane with the spinning anemometer/broken rain gauge/thermometer; and speaking of rain gauges, in addition to the broken one I have 3 more...two "go lookats" and one wireless. Oh yeh, and a pie pan on the mat where I sometimes overhead water the potted perennials, judging the water amount according to the content of the pie pan. Er, does that count? *grin

Shoe (who also has five online weather pages saved to his favorites and see is it now 50 in Doug's town, 40 where Susan is, and GymGirl is suffering from or enjoying a temp of 66!)

Happy Day, All!

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 7, 2012
9:14 AM

Post #8958083

She looked out the window this morning and saw, yet, another sprouting broccoli head, and she is DEFINITELY suffering!!!

Aaaaarrrrgggghhhh!

God, PLEZ send some 45-50 degree weather to Houston for eight weeks!

Linda
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 7, 2012
11:39 AM

Post #8958187

GG what's with the broccoli anguish?

Balmy 50 degrees here. Was suppose to get to 60 today.

Already counted the traveling meat thermometer. 4 weather band radios not including the car. Two are gifts from his parents as we do get a lot of tornadoes. Most all of the radios obnoxiously beep/buzz for everything and not just tornado alerts. I think he has a phone app that you can set for what you want it to sounds on. The phone app in not counted above.

Are you counting water pans in the yard? Because there are multi water pans in the yard for the dog, birds, and butterflies. Never occur to me he might be monitoring the amount of rain water via the watering pans.

No spinning anemometers but we can get that info on-line from the local weather monitoring station a couple of blocks away at the golf course.

BTW - He has seperate multiple apps (phone & PC) for the weather. Not just weather pages. :-)

Horseshoe
Efland, NC
(Zone 7a)

January 7, 2012
5:12 PM

Post #8958516

Heheheh, you're killin' me, Susan! :>)

Next thing ya know we'll be having "weather roundups" for DGers.

Go pick that broc head, Linda. At least it'll kick in some side shoots to form, eh?

Shoe

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 7, 2012
7:01 PM

Post #8958648

By time I got outside, there were cute little bees buzzing all over those broccoli sprouts like it was Christmas day in the beehive.

And, since I'm learning to live in harmony with the wildlife, I figured they could enjoy it. Maybe they'll return the favor at tomato pollinating time -- not that I need them. My crosswinds did all my pollination last season.

Best harvest ever!

Linda

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 9, 2012
5:17 PM

Post #8961180


Temperature fetishists: what's funny about that?!? It makes total sense to me, inquiring minds want to know!

I would love to have remote-monitoring / recording thermometers for my compost heap and future solar cold frames and greenhouses. All it would take is a link to my PC's wireless network. Of course that should drive motorized vents and maybe shades, fans and electric heaters ... programable alarms that would send text msgs to my cell phone ...

interface the watering system to rain gauges ... plus maybe a motion sensor so I could water any cats that think my raised beds are catboxes.


>> Opening the top from time to time to allow an air exchange and excess moisture out is necessary

Hmm, "from time to time"! Leave it closed to keep the heat in MOST of the time, and vent it only occasionally to deter fungus. I hadn;t thoguht of that, it sounds smart.

>> styrofoam Grape containers from our Winco store, and plan to use them as perimeter insulation for my seed flats

"Perimeter insulation" for seed trays: I like it!

>> a small electric heater

I never thought of that, assuming it was too expensive.
What is the cost of 8 heat mats? Maybe $160?
At 20 cents per kilowat-hour, that would buy 800 KW-HR.

If a small electric heater is 800 watts that would run it for 1,000 hours of ON time.

Say it only runs an average of 10% the time, all day, to hold temperature.

That's 10,000 hours or 417 days or 60 weeks. If the heated part of the seed-starting season is 6 whole weeks long, the pay-back period for 8 heat mats might be 10 years or more. Maybe more.

It looks as if commerical heat mats are a huge capital investment compared to the surprisingly small recurring cost for electricity to just heat a small growing room!

Hunnh!

And if you had some fabric to make a tent around your seed shelving, I bet the heater would only run 5% of the time, like right after you opened the tent to look at them. Maybe a drywall enclosure on two sides and above, but now you're puttting tens of dollars into buying drywall. One plus is that drywall is fire retardent, so if the heater shorts out, the scorch will be contained.

Prohably the best bargain would be way to spread 1-2 heat mats over multiple trays, raised each tray 5-10 degrees above ambient. Then you could lower the setpoint for the seed-shelf-tent by 5-10 degrees.

No, the best bargain would be a tent or drywall around the seed shelves, positioned over a heating vent. That would keep the seeds 10-20 degrees warmer than the rest of your house, but the heat would still escape the tent and keep you as warm as it would have anyway.

But now you can keep your whole house at 50F, oh boy, think how much electricity that will save! Enough to pay for another rack of shelving and lights!

JoParrott
Richland, WA
(Zone 7b)

January 9, 2012
5:56 PM

Post #8961257

Rick, you gots too much time on your hands! :)

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 9, 2012
6:29 PM

Post #8961291

Waaaaaaaay too much time.
kmom246
Murfreesboro, TN
(Zone 7a)

January 9, 2012
7:52 PM

Post #8961386

I must admit, though, that Rick is pretty entertaining! :-)
cornish2175
Charleston, SC
(Zone 8b)

January 10, 2012
5:04 AM

Post #8961580

Like your thinking Rick, foung it would cost me about $86. to buy 4 heat mats plus then you would need a temp guage to keep from cooking your seedlings plus having to PLUG in 4 more things- I bought a small elecric heater which is on its own outlet and run it at night on economy setting. With the door to my plant room shut it raises the night air temp by about 8 d. then with all the florescents on during the day it is quite toasty there. I have had excellent germenation this year with this method, my tomatoes had their first leaves in 6 days.

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 10, 2012
10:54 AM

Post #8961986

Way to go , Cornish2175!

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 10, 2012
6:11 PM

Post #8962608

>> With the door to my plant room shut

I think that is the key to any heat-managment issue. Contain the heat where you want it, and then size the heater to the space.

I just saw a heat mat for $60 in the Pricey Parks catalog. 23" x 15". I would laugh uproariously, but they mention a chrome wire cage to allow air circulation. With no insulation! So the heat will just dump straight out into your room and the soil will still be room temperature. What a waste!

Of course, you could buy a $25 equivalent mat and then bring a wire rack home from Goodwill for $2, maybe folded newspapers for insulation, saving $33 or 165 KW-hrs of electricty!

Or skip the mat and spend the whole $60 on power for a small space heater, closing the door at night.
.

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 10, 2012
8:45 PM

Post #8962867

I am enjoying this thread.
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 10, 2012
11:13 PM

Post #8962991

Rick - You are missing the cost of the gas or electric heater in the cost estimate above.
cornish2175
Charleston, SC
(Zone 8b)

January 11, 2012
5:04 AM

Post #8963079

I found my heaters on sale at Lowes for $38. + tax. Granted, they are small heaters and would not heat my large living area but perfect for the sunroom and the plant room. I have not seen a significant raise in the electric bill but since we heat a 16' swim spa year round! We have been lucky this year with the cold- only had 1 night that temps dipped below 30 but mostly the temps have stayed 40-50 at night then spiking to 70-80s during the day. Its a rollercoaster and my poor plants in the ground are very confused.
rjogden
Gainesville, FL
(Zone 8b)

January 11, 2012
7:20 AM

Post #8963185

RickCorey_WA wrote:No, the best bargain would be a tent or drywall around the seed shelves, positioned over a heating vent. That would keep the seeds 10-20 degrees warmer than the rest of your house, but the heat would still escape the tent and keep you as warm as it would have anyway.


As long as we're daydreaming, I can immediately foresee one problem with this arrangement: it would be very difficult to keep your media from drying out and killing the seedlings. Cold air is not capable of carrying as much water as warm air, so even at saturation the absolute humidity is low. Heating it causes the relative humidity to drop. Warm moving dry air evaporates moisture from porous growing media very quickly.

Supplementing moisture by adding a humidifier to the equation might help - but it's one more thing to keep track of. Every time the forced air stops, the humidity inside the drywall enclosure will immediately skyrocket. Ever seen mold and mildew growing in drywall? I have. You don't want to. (You could ask the survivors of Katrina about molds in drywall).

After some 40+ years of trying different growing arrangements, I've learned the KISS principal definitely applies. There's a reason so many people use heating mats despite the up-front cost.

-Rich

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 12, 2012
2:17 PM

Post #8965135

>> Rick - You are missing the cost of the gas or electric heater in the cost estimate above

I am assuming that you already have a small space heater, but, true, that is also a "capital expense". Similarly, it doesn;t cost extra to shut the door, and the furnace or wtaer heater was going to be running the same amount anyway.

maybe there are two different ways to comapre schemes: "fairly", where you include all costs, or "incrementally", where a person only looks at what she or he needs to add to pre-existing expenses to adopt that scheme.

Thus, for someone who already has plenty of heat mats for all their trays, "heat mats" are a clear winner.

For someone with no heat mat, but with a small, warm room they can isolate plus any random small extra space-heat source, that is a clear winner.

I'm a big fan of insulating trays if you use heat mats, but, realistically, how many years would you need to run a 29 Watt heat mat to pay back the cost of a sheet of drywall? I forget how much the 4x8' sheets cost. I bought 2, 2'x2' squares for around $3-4 each. To justify my favorite scheme, I would have to say that insulation lets a low-powered mat raise the temperatue higher, or warm 2 trays instead of one.
SusanKC
Shawnee Mission, KS
(Zone 6a)

January 12, 2012
3:10 PM

Post #8965189

I was just pointing out that a cost evaluation would have included the cost of the heaters. We don't own portable heaters as I know them to be a fire hazard. I tend to review what the safety and cost issues are for a project. Our basement is heated. We choose to keep the basement temperature lower in the winter and higher in the summer. The tradeoff is that we use matt heaters until the plants go outside.

I'm assuming the issue about the drywall is not the cost of the drywall replacement but the cost of the clean-up (or tear-down) if black mold becomes an issue. Black mold is considered a hazardous item and sometimes the house involved is condemned.


Hope this helps clarify.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 13, 2012
10:23 AM

Post #8966161

Good points. I lived for a while in a very humid basement in New Jersey that was saturated with mold. Not pleasant. I think that is a bigger consideration if the whole germinating room is sealed and humid. If an insulating tent is put around the trays, it seems that only the tent would be prone to collecting moisture and mold.

Maybe the mold problem is mitigated by the fact that most people would only start seeds a few months per year, and the rest of the time, the warmer room would tend to bake itself dry.

Managing humidity in an enclosed space with a lot of moist soil is necessary. Venting the space freely means you'll have to replace the heat lost. If the insulating walls are cooler than the soil, (as they would have to be), humidity will tend to condense on the walls' inner surface.

On the other hand, the walls will be warmer than the surrounding space, so humidity will tend to evaporate from the walls outer surface. How would tjat work in practice? I'm not sure, but if I do this, I will paint the inner surface of the walls with waterproof paint or line them with well-sealed plastic.

Maybe, for small spaces or a well-insulated grow space, there would be some appliance that produced enough heat to warm the space without excessive fire hazard. I'm thinking of 100-200 watts, like a few light bulbs or maybe an iron. I know that there are baseboard heaters designed to heat rooms, some portable and some designed to be built-in, and I thought they were sarfe to run unattended.

Soil-heating mats are one extreme of size: 27 or 40-50 Watts heating just a few square feet 3" deep. Very power-efficient if you can afford the heating mats and thermostats.

Heating an entire greenhouse, or your whole house, is the other extreme.

Heating one small room or a "tent" around several trays would be a comprpmise between start-up costs and ongoing expense.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 13, 2012
11:01 AM

Post #8966220

Oh I don't know Corey. I have a lean-to type greenhouse with windows on three sides and a clear polycarbonate roof. I put bubble wrap between the ceiling joists in winter and make sure all my vents are covered by 2-3" thick foam stapled in place. I use an oil filled radiator heater ~$80 at Lowes that I set to come on if the temps drop below 50 and it is doing quite well at a very reasonable cost. Makes a great place to escape to in the winter to drink a few beers and listen to the blues too!!! I think it gets used more in cooler weather than any other time! I keep a lot of plants in there not so much to propagate yet but to just see if I can keep them alive during the winter. I have Amaryllis blooming, Boston Ferns showing new growth, a Poinsettia I've had for about 4 years now. It's fun just to go up there and play around. (No I never had a playhouse as a kid!!)

Doug

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 13, 2012
11:55 AM

Post #8966281

That sounds like a great spot, and better-insulated than most.

Wish I could join you there, I'd bring the beer!

Corey

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 13, 2012
2:49 PM

Post #8966484

Not Oly I hope!!!

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 13, 2012
3:21 PM

Post #8966521

I never beard of Oly Beer ("Olympia"?) so I looked it up. Given all the really good microbrews around here, I'm surprised no one tried to revoke their right to use that name. It sound like Rolling Rock from Back East: like half-bland American lager and half water. Yuck! I bet slugs would like it.

Maybe Full Sail Amber or anything from Deschutes or Bridgeport Brewing.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 14, 2012
6:23 AM

Post #8967112

Olympia and Rainier was what I drank when I was stationed on Whidbey Island in the late 70's. Microbreweries were non-existant back then. Still have a lot of fond memories of the PNW. Can you get beer from Utah breweries there? If so try to find Provo Girl Pilsner. We had it in New Mexico, Arizona and Utah back in April/May. Pretty good pilsner, but cannot get it here.

Pic from top of Mt Erie looking back towards Whidbey Island.

Doug


This message was edited Jan 14, 2012 9:24 AM

Thumbnail by postmandug
Click the image for an enlarged view.

MaryMcP
Phoenix, AZ
(Zone 9b)

January 14, 2012
8:45 AM

Post #8967257

Rainier - the green death. :-) What we called it when we lived in the PNW many years ago. Harp, Guinness or Smithwicks these days.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

January 14, 2012
12:40 PM

Post #8967480

With Mc in your name of course it has to be Irish beers!!!! I kinda like Fullers London Pride myself..

Doug
MaryMcP
Phoenix, AZ
(Zone 9b)

January 14, 2012
1:29 PM

Post #8967597

;-) We won't even start on the whiskey's...

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

January 15, 2012
5:33 PM

Post #8969134

>> Provo Girl Pilsner

If I see it ... I don't recall having seen a Utah brewry locally.

Corey

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

January 29, 2012
7:12 AM

Post #8986409

I finally broke down and purchased a heating mat and thermostat. With free shipping they were $50.94 which I thought was a good price.

http://www.amazon.com/gp/product/B000NZZG3S/ref=ox_ya_os_product
http://www.amazon.com/gp/product/B0001WV010/ref=ox_ya_os_product

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

January 31, 2012
1:17 PM

Post #8989653

Check out THIS heating mat...

http://allthingsplants.com/thread/view/7543/How-ingenious/

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

February 1, 2012
8:05 AM

Post #8990617

Gymgirl - thanks for the link - I have never heard of an electric roaster. I had thought of Horseshoe's idea of using the oven, but then thought of the mess I'd have to clean up if I spilled "dirt" in it!

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

February 1, 2012
8:07 AM

Post #8990620

A roaster would be PERFECT! Almost like an incubator.

stephanietx

stephanietx
Fort Worth, TX
(Zone 8a)

February 1, 2012
9:47 AM

Post #8990748

Brilliant idea! Now I just have to find a roaster! LOL Leave it to Patricia to come up with a wonderful idea.
kmom246
Murfreesboro, TN
(Zone 7a)

February 5, 2012
9:53 AM

Post #8995524

BTW, I saw several roasters at the goodwill for sale for cheap when I dropped off donations the other day.
JoParrott
Richland, WA
(Zone 7b)

February 5, 2012
10:55 AM

Post #8995570

If you do many flats you would need lots of roasters!

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

February 5, 2012
11:37 AM

Post #8995603

Stagger the germination.

stephanietx

stephanietx
Fort Worth, TX
(Zone 8a)

February 8, 2012
9:18 AM

Post #8999139

You could probably rig a way to stack them in the roaster, too.
lorvan
Hamilton, ON
(Zone 5b)

February 10, 2012
11:55 AM

Post #9001907

I have never really understood the need for heat mats... maybe because I have my seedlings starting in a spare room which is the same temp as the rest of the house... roughly 70F. But I find that my shop lights give off quite a bit of heat for the shelf above it. Works good enough for me, so I simply can't justify spending so much money on mats. I start my plants from seeds for two reasons... first, as a hobby, and second, to save money on buying plants in spring.

Gymgirl

Gymgirl
SE Houston (Hobby), TX
(Zone 9a)

February 10, 2012
1:04 PM

Post #9001970

I hear yah, Lorvan. Same here!

And, with the Roots Organic potting soil I just started some seeds in (as an experiment compared to seeds started in Sunshine Plug and Seed Starter mix, with no amendments), unless you live in the North Pole, you should NEVER need a heating mat!

I never saw seedlings take off so fast and turn out so healthy! The stuff is $$$ for a lot of us at-home gardeners (me included), but, it's worth a shot to buy one small bag and see what it does. You can decide from there to continue or not.

In my case, I'm going to work on purchasing the amendments individually, and mix up my own stuff. I think I could come out a lot cheaper and get close to the same soil make-up.

Linda
JoParrott
Richland, WA
(Zone 7b)

February 10, 2012
1:34 PM

Post #9002005

Doggobnit- I gotta go find some Roots Organic! Just can't stand hearing all the good about it and not having any!!!

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

February 10, 2012
2:02 PM

Post #9002060

>> unless you live in the North Pole, you should NEVER need a heating mat!

I keep my house around 56 F when I'm not home or asleep (almost all day 5 days per week), and 60 F when I am home and awake, uless I have guests.

A lot of seeds germinate faster and more consistently at 70-75 than at 55-60.


drthor

drthor
Irving, TX
(Zone 8a)

February 10, 2012
3:20 PM

Post #9002167

I luv my heating mat
JoParrott
Richland, WA
(Zone 7b)

February 10, 2012
4:58 PM

Post #9002265

Me too- heating mats do get the seeds motivated to pop---
rjogden
Gainesville, FL
(Zone 8b)

February 11, 2012
3:06 PM

Post #9003220

RickCorey_WA wrote:>> unless you live in the North Pole, you should NEVER need a heating mat!

I keep my house around 56 F when I'm not home or asleep (almost all day 5 days per week), and 60 F when I am home and awake, unless I have guests.

A lot of seeds germinate faster and more consistently at 70-75 than at 55-60.

Yep. Peppers & eggplant, cukes and squash (started in peat pots, nice if you're up north with a short season or just impatient ;o). Just to name a few more common ones. There are a lot of tropical plants that need more heat to germinate, and if you want blooms or fruit the first year that's a good way to do it. Heat mats only require the space they take (they come in a variety of sizes), an electric outlet and maybe a grow light. It sure beats building an entire hot bed or cold frame if you don't need that much. And if taken care of (not left bent or under piles of heavy boxes, or stepped on) they should last a long time.

I'm really appreciating mine right now. I've got peppers and eggplant started that would be rotting in my garage otherwise (just hear they've dropped the overnight forecast again - to 23F! Sure wish that global warming would get here! [vbg]

-Rich

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

March 29, 2012
11:12 AM

Post #9062011

Update to my January 29th Post #8986409

I have been delighted with the heat mat and thermostat. I've been using them in conjunction with a Jiffy greenhouse I purchased at W-mart. It has the same dimentions as the heat mat.

I did not use the pellets that came with the greenhouse as I prefer my own soil recipe. The 3oz plastic Solo cups I use for germinating seeds fit perfectly under the greenhouse's dome. I had to cut a small up-side-down "V" in the side of the dome to accommodate the heat map's probe.

Today, I purchased three more Jiffy greenhouses.

Two questions: Is there a way I can join more heat mats to the thermostat? Or do I have to purchase a thermostat for each heat mat.


gardadore
Saylorsburg, PA
(Zone 6a)

March 29, 2012
11:41 AM

Post #9062045

Honeybee,
Maybe you could use a 6 prong power strip, plug the mats into that, the strip into the thermostat, and the thermostat into an outlet. Or a multi pronged extension cord, depending on how many mats you have. Someone else who knows more about electricity than I do would have to tell us if this could overload the system! The only problem I see with it is that each mat might be at a different temp so that it would be hard to regulate more than one at a time! Just thinking out loud. I love to solve problems even if I don't know what I am talking about but I would probably have tried this route first. I also have two mats so would like an answer to your question that is safe and works!

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

March 29, 2012
11:55 AM

Post #9062058

gardadore - thanks for your answer. I, too, wondered whether plugging more than one mat into the thermostat would overload it in some way.

Guess we'll both be waiting for someone more knowledgeable to give us an answer. :-)

dreaves

dreaves
Hutto, TX
(Zone 8b)

March 29, 2012
2:50 PM

Post #9062249

Honeybee,

You may want to consider a thermostat per heat mat. The problem with tying together is that the mats may heat differently, or the soil characteristics in each tray may differ (moisture, air, etc.) One tray, with the sensor, might be fine, but the other mats, that were heating trays without sensors could vary in temperature --to hot and the seeds are cooked, too cool and they germinate slowly or not at all.

David
gardadore
Saylorsburg, PA
(Zone 6a)

March 29, 2012
9:11 PM

Post #9062727

David,

I think you are right. That is something I also wondered about above (besides possibly burning the house down!), that each mat would have different trays on it with various needs. Actually I find that I don't need a thermostat at all. I monitor the trays several times a day and when something sprouts it immediately goes under the lights so the plants don't get too tall and leggy. I also shade the trays with cardboard bent on its sides so that the sun doesn't hit the trays directly (They are on the floor in front of a picture window) which could heat things up too much, especially since the trays have plastic covers on them to keep the moisture in.
MaryMcP
Phoenix, AZ
(Zone 9b)

March 30, 2012
2:25 AM

Post #9062797

When my heat mat is giving too much heat to the seedling tray, I place the mat directly on a piece of ceramic tile. That way the heat is disbursed down to the tile and away from the seedling tray. If I want more heat to the seedling tray, I will use a standard dining place mat, which happens to be the perfect size, to insulate between the piece of tile and the seedling tray. This sends more heat up to the tray and away from the tile. Not very high tech but it does work.

postmandug

postmandug
Bardstown, KY
(Zone 6a)

March 30, 2012
7:32 AM

Post #9063009

I just use a couple small pieces of wood to elevate the seedling trays so they are not sitting directly on the mat. Worked great so far this year.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

March 30, 2012
2:09 PM

Post #9063439

David, I think you are correct in thinking each tray should have it's own thermostat. Guess I'll have to re-write the gardening budget (again) for next season LOL

gardadore, Mary, and postmandug

I have the heat mat on a wooden shelf. So far this has worked out very well.

There has certainly been a difference in the number of successful seeds sprouting, and the time between sowing and sprouting has increased exponentially.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 30, 2012
3:45 PM

Post #9063553

Heat mats are very low-current low-power devices. A 4-tray mat pulls about as much as one 48" flourescent bulb,
so one 2-tube shop light pulls about as much power as enough heat mats for 8 trays.

I see a one-tray heat mat rated at 17 watts, and a 20"x20" (4-tray) mat rated at 45 watts.

I don't think many of us could afford to buy to buy enough heating mats to overload a circuit breaker, size-outpet strip or a thermostat. I saw one thermostat rated at 1,000 Watts maximum, which woiuld be 140 of the single-tray mats or 22 of the 4-tray mats.

A 20-amp circuit breaker ought to be around 2,400 Watts (so there seems to be plenty of safety margin inless you have 2,000 Watts of light bulbs ... which would be 37 to 62 48" flourescent tubes.

I think a 48" T5 one-tube flourescent tube pulls around 54 W
and a 48" T8 tube pulls 32 W.
Standard old-fashioned T12 48" tubes pull 40 Watts (but give less light).
(There are probably other models with somewhat different ratings).


But if my numbers are right, you could run all these together on one curcuit:
- 8 48" T5 2-tube flourescent fixtures PLUS
- 8 48" T8 2-tube flourescent fixtures PLUS
- 8 20"x20" 4-tray heat mats
...
for a total of only 1,480 W ...
and one 20-Amp curcuit breaker could handle it all with 920 W to spare.

Do flourescent fixtures have startup inrush currents of double their rating?
Maybe check with an electrician if you have more than 12-16 shop lights all starting up simultaneously.
Horseshoe
Efland, NC
(Zone 7a)

March 30, 2012
7:59 PM

Post #9063847

Those are good guesstimates, Rick/Corey. I'd feel perfectly comfortable going with that.

"David, I think you are correct in thinking each tray should have it's own thermostat. Guess I'll have to re-write the gardening budget (again) for next season"

Honeybee, you won't need a separate thermostat for each mat. I run 25 feet of heat mats off ONE (edited cus I wrote "off" twice instead of "one-sorry) thermostat and have done so for quite a few years now.

What IS important though is to keep in mind your pot size, or tray size, and the soil medium. (I think someone above may have touched on this.) Since you would normally be using the same seed starting soil/medium you should have no problem with the medium differences. What would come into play would be having your thermostat probe in a 4" in pot (for example) but then have your seed trays in various/different sizes (row trays, quart pots, gallon pots, etc). If your probe in the 4" pot is telling the thermostat to cut on or off according to the temp of that pot then your other pots, be they larger or smaller, will either never be heated enough or could be heated more than necessary. So...

...basically, keep your seed starting containers the same size as the container the probe is in and you will be good to go.

Hope this helps.
Shoe

This message was edited Mar 31, 2012 12:22 PM
gardadore
Saylorsburg, PA
(Zone 6a)

March 31, 2012
8:36 AM

Post #9064227

Thanks, Shoe, that was very helpful and should solve the problem for a number of us!!

Jessica
Horseshoe
Efland, NC
(Zone 7a)

March 31, 2012
9:26 AM

Post #9064280

You're welcome. I couldn't do w/out my heat mats, starting thousands of seeds on them as well as keeping the seedlings at a much warmer temp than they would normally be due to my refusal to heat my whole greenhouse. It is much easier (and cheaper) to heat the soil than to heat the air space in a big room or greenhouse.

Shoe

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JoParrott
Richland, WA
(Zone 7b)

March 31, 2012
12:53 PM

Post #9064428

Shoe-Hi- haven't heard from you in awhile- now I see why!!You been growing! That's a nifty setup- I'm doing the same thing on a much smaller scale- I keep clear plastic tents around my trays that are on the heat mat.

Thumbnail by JoParrott
Click the image for an enlarged view.

Horseshoe
Efland, NC
(Zone 7a)

March 31, 2012
3:49 PM

Post #9064649

Howdy, Jo...

Your tents are a great idea and will help keep your heat mat electricity down, too by holding in the heat longer. And I know you well enough that you are venting them so the moisture build-up isn't excessive.

Yes, very busy here so can only post when entirely exhausted or fizzled out! *grin. This morning I splurged and had extra coffee (Luzianne!) so used that excuse to read some DG!

Shoe
JoParrott
Richland, WA
(Zone 7b)

March 31, 2012
4:08 PM

Post #9064677

Yes, I pull the plastic back and open the greenhouse up during the sunny days. I have both heat & fans when needed.My little tomatoes are looking good. Funny, though- the best looking ones right now are from a delicious Roma tomato from Albertson's! I am aware that it may not come out a desirable tomato, but I like to experiment.
steadycam3
Houston Heights, TX
(Zone 9a)

March 31, 2012
4:47 PM

Post #9064725

Rich, as I understand it, global warming just makes weather more extreme, not necessarily hotter everywhere.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 1, 2012
7:01 AM

Post #9065261

Horseshoe -
Quoting: you won't need a separate thermostat for each mat


That's very reasuring.

How do you hook them up to each other? (I'm not very electrically minded - LOL)

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

April 2, 2012
2:39 PM

Post #9067247

Shoe,

I loved the "shrink-wrapped shelving unit" inside a hoop greenhouse.

Do you have any clear plastic domes
over the trays,
inside the shrink-wrap
under the hoop tunnel
that Jack built?

I read about someone who grew lettuce all winter in Maine. He had at least three layers of heat protection. I think it was:
1. floating row covers
2. a low hoop tunnel, like 6" to knee-high
3. a walk-in big tunnel.

I like to think that he started his seeds under cloches under the row cover under the low tunnel under the hoop-house!

Since I worried even more about humidity in the past than I do now, I took off my "humidity domes" ASAP. But I kept a sheet of drywall (sheet rock) UNDER the heat mat, so al;l the heat went up and none went down.

Now I think that my sheetrock Bottom should have had Sides, so that it became a Hot Box.
Horseshoe
Efland, NC
(Zone 7a)

April 2, 2012
6:29 PM

Post #9067511

Honebee...

Your thermostat has a plug-in (outlet) where you plug in your heat mat. That is where you would plug in a power strip. (Those are what give you more than one plug-in, perhaps like you have for your tv, dvd player, am/fm stereo, etc.) Then you plug in your heat mats to the power strip. Your thermostat will cut on and off according to the temperature sensor you've stuck in a selected pot/tray/whatever. Each mats temp will be governed by the pot/tray/whatever that your sensor probe is in, which is why it is important to have them close to the same size, same soil medium, etc.

RickCorey...

When I have a few trays on the heat mats, especially peppers or egg plant seeds, I put the plastic domes on them to help hold in moisture and heat. Once they germinate I take them off so there is no excessive build-up of moisture and they get proper air/gas exchange.

The "heat cabinets" (as I call them) do double duty sometimes and during those times I'll put umpteen trays of other seedling in them by cross-stacking them. The plants/seeds that need the direct heat are on the mats themselves; the germinated trays that need heat but not as much go on top of the others. IN order to do this I'll put another tray, as a lid, over the bottom trays (on the mat). Those trays hold in the heat for the still-germinating seeds and also give support to the trays on top of them. Once the plastic is pulled down for the night all is comfy and cozy.

Hope this helps.
Shoe

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 3, 2012
9:16 AM

Post #9068130

Shoe - thanks for the info. I have a couple of spare power strips, so I'll use one as you directed:

I plug each heat mat into a power strip.
Plug the power strip into the thermostat
Plug the thermostat into the wall outlet
Poke the temperature sensor into one of the pots

Did I get that right?

The cups and soil I use are all the same, plus I'll be sowing seeds that require pretty much the same temperatures as each other.
Horseshoe
Efland, NC
(Zone 7a)

April 3, 2012
5:12 PM

Post #9068604

You got that perfect, Honeybee. Exactly correct.

And yes, having all the trays the same size helps for even germination. As time goes on you might want to get double-duty from your mats by cross-stacking some trays with seedlings that will benefit from the upward rising heat but yet not be the same (80) temp as what is on the mat.

Shoe (off to check my g-house plants)

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

April 3, 2012
6:46 PM

Post #9068736

>> I'll put umpteen trays of other seedling in them by cross-stacking them. The plants/seeds that need the direct heat are on the mats themselves; the germinated trays that need heat but not as much go on top of the others. IN order to do this I'll put another tray, as a lid, over the bottom trays (on the mat). Those trays hold in the heat for the still-germinating seeds and also give support to the trays on top of them. Once the plastic is pulled down for the night all is comfy and cozy.

That's a new one on me! Stacking trays inside a heat box. Great idea. After all, heat isn't "used up" by passing through one tray. It's only lost if there is an air leak out of the enclosure, or by conduction through the plastic.

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 4, 2012
9:11 AM

Post #9069507

Shoe, and Rick,

Thanks for the great ideas which are practical and will save energy.
Horseshoe
Efland, NC
(Zone 7a)

April 4, 2012
4:17 PM

Post #9070029

"That's a new one on me! Stacking trays inside a heat box."

Yeh, it just kinda evolved out of necessity, Corey. I think I'm going on more than a decade using that "system". I admit it is time consuming morning and evening because unload those heat cabinets and put all the seedlings on the g-house tables so they get their daily sunlight, then move them back, restacking them in the evening so they get their required heat. Boy did I used to grumble alot but nowadays it is just a given, needs to be done.

Honeybee, your heat mat will open up a whole new world for you. Enjoy it!

Shoe

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 5, 2012
8:29 AM

Post #9070675

Shoe -
Quoting:Honeybee, your heat mat will open up a whole new world for you. Enjoy it!


It has and I am :-)

Wish I had the mat during the spring of 2011 when it was so cold! I had a terrible time getting anything to sprout.

I'm already planning to purchase three more mats to go with the one I have, and use them with your idea of plugging them all into to the one timer.

The shelving unit I use to sprout seeds has room for at least three more 4ft shop lights. Hopefully I'll have some cash to buy those too next year.
Horseshoe
Efland, NC
(Zone 7a)

April 5, 2012
9:27 AM

Post #9070728

Wow! We'll be setting you up to sell your produce at a local farmers' market soon! :>)
You're on a roll!

Happy that you're happy!

Shoe

HoneybeeNC

HoneybeeNC
Charlotte, NC
(Zone 7b)

April 6, 2012
6:46 AM

Post #9071725

Shoe - [quoteWe'll be setting you up to sell your produce at a local farmers' market soon![/quote]

LOL - no, I'll just keep sharing it with the neighbors :-)

Although... if the County ever make this a "through street" I might put up a road-side stand! Right now it's a "dead end" street, but there is a new development growing just two houses away and our road continues on the other side of a barrier. I suspect the street will be extended once the development is completed.

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