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Seed Germination: To Bleach or Not to Bleach? What is best to reuse seed trays

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DanSt
Bismarck, ND

February 25, 2013
8:51 AM

Post #9430987

I've been starting my own garden veggies for the last few years and now I have quite a collection of used trays and cells. Each year I purchase new cells but I really would like to start using my supply. I've been reading that using bleach is a good way to sterilize stuff but I've also read that using bleach is not a good idea. Any thoughts on Bleach or Not to Bleach?
trc65
Galesburg, IL

February 25, 2013
10:47 AM

Post #9431140

I have been using bleach for about 20 years to sterilize both in commercial operations and personally. I don't know why anyone would say it is not a good idea.

Remember, before you bleach your trays/cells, they need to be washed and not have an overabundance of potting soil/dried plant material on them. I usually wash trays cells as soon as they are emptied that way they are ready for bleaching when I get to it.

I use a large Rubber made trash can for bleaching, large plastic totes also work well - all depends on the quantity of material you have.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 1, 2013
6:41 PM

Post #9435975

I only garden on a tiny scale, but I also try to wash inserts and trays and plastic pots as soon as I get the soil out. I think it is good to get all visible soil off ASAP, so soil organisms aren't encouraged to form spores.

Well, I spray them with a hard mist and spray from a garden hose hand sprayer. I let batches of trays & pots stand a while, wet, to soften up, and try to spray the rest of the soil off. It helps to have some kind of corral like chicken wire or fencing to hold things in one place while I blast them.

(The mist conserves water, but the spray scrubs harder. I use the spray in short blasts and use the mist continuously.)

Then I rub and scrub any remaining visible soil or stain that didn't come off easily and and spray again.

(Typically, they next sit in rain and sun for a while. I'm sure that rain and sut bring in more microbes, but hopefully few plant pathogens.)

Then, when I have time and I've collected a lot of plastic gadgets, I make sure they're still visibly clean and spray them all again anyway, to get the dust off, to soften remaining films, and to protect my dishwasher and drainage pipes.

Then I run them all through a dishwasher, briefly. I fill it up and run it for a few minutes, then remove that bunch of trays and replace with other trays. So one complete cycle of the dishwasher might handle 5 batches of trays. Afterwards, I let the soap sit on the trays for a while, then rinse them all with the hard mist from the garden hose, outdoors.

Probably a big barrel of bleach is better, but I found that kind of dunking very tedious and tiring with just a 5 gallon bucket. At least I get mine visibly clean, then hit them with hot, caustic , soapy spray.

If I start seeing plant diseases, I'll have to find a bleach-dunking method that works for me. Maybe hand-spraying in my bathtub. That would have the side-benefit of getting my tub really clean!




mom2goldens
Carmel, IN
(Zone 5b)

March 3, 2013
4:24 PM

Post #9437824

I've been using bleach on my trays/cell packs/pots/capillary cloths for years, and have never had a problem with diseases or damping off. I think it's important to use the proper amount of bleach, and to rinse thoroughly.

I do try to remove as much dry potting mix before soaking, and I use a bottle brush to clean out the pots/cell packs. It's rather a labor of love, but my seedlings and plants have all thrived in pots/trays that have been used for several years.

Linda

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 5, 2013
2:14 PM

Post #9439850

How many years do your capillary cloths last? Are they commercial, and what brand name?

I've been using cotton flannel, and they look pretty beat-up after a few months in a tray, especially if I s0pill any soilless mix.
mom2goldens
Carmel, IN
(Zone 5b)

March 5, 2013
5:47 PM

Post #9440082

Rick: I bought some capillary mats from Lee Valley (actually, it's a large size that you can cut to size) that holds up really well. I also purchased some from my Master Gardeners group. I will check where they purchase from because they are really sturdy also. At MG, we pay cost, so I can buy them for $1 each.

Will report back as soon as I can find out.

My mats from both sources are at least a few years old and have held up well to a mild bleach solution.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 5, 2013
6:16 PM

Post #9440107

Great. I've been looking for an excuse to order from Lee valley since I saw their tiny seed spoons. Others have praised the Lee Valley cap mats.

I keep hoping they will re-stock either of certain small-knife-sharpening guides that have been unavailable for decades. Mine both got lost during a move. "Buck Honemaster" was one of them.

Thanks!
altagardener
Calgary, AB
(Zone 3b)

March 5, 2013
9:02 PM

Post #9440241

I wonder if it may depend on the conditions in your area - if you're in a humid area, is there a larger amount of fungal/mildew spores floating around and a greater propensity for fungal disease to spring up where conditions favour it, both inside and out? Anyway, i've always gardened in relatively dry, low humidity climates and have never bothered bleaching pots, or even washing them, or sterilizing soil or any similar measures. Over many years and starting a lot of species from seed each year, I've never been bothered by damping-off. I also re-use soil from year-to-year, as I usually knock most of the soil off the roots prior to planting seedlings in the rock gardens.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 6, 2013
12:07 PM

Post #9440885

AltaG, I think you're right. It depends hugely on local conditions.

Dr. Carolyn, in the Tomato forum, made a point about safeguards against diseases like soil diseases. (For example, rotating cops.)

If you never have a certain problem, don't worry about it, and don't take burdensome measures against it. If certain pest or disease isn't a problem in your climate or your soil type or under your conditions and practices, "it ain't broke".

But when you DO have problems with X, Y, or Z, then you do have to discover and use effective counter-measures against them.
mom2goldens
Carmel, IN
(Zone 5b)

March 6, 2013
5:49 PM

Post #9441248

Rick: the seed spoons from Lee Valley are my favorite gardening tool outside of my garden knife. As I get older (and it gets harder to see tiny seeds even with my bifocals) the spoons are a godsend--really easy to get just the right amount of seed where you want it placed.

Lee Valley occasionally runs free shipping--sign up on their website for notifications. (And no, I don't work for them LOL)
birder17
Jackson, MO
(Zone 6b)

March 6, 2013
6:14 PM

Post #9441274

I live in a hot humid area. I don't take the time or spend the energy bleaching my pots. I have never had a problem with mold.
Pfg
(Pam) Warren, CT
(Zone 5b)

March 6, 2013
9:10 PM

Post #9441451

I had a huge problem with damping off the first year I I tried to start seeds for this garden. I had been quite successful in a previous zone so it was quite a shock, I can tell you! Thanks to DG, I began using peroxide for all watering ( formulas vary some, I use 10:1), including wetting the soil mix before use. That was the end of it. Also since then I stopped worrying about sterilizing anything. The only other thing I do religiously is sprinkle cinnamon on top of the cells and pots after sowing or transplanting, which prevents gnats. I think I read somewhere that it may also act as a fungicide, but I'm not sure about that.

Pam

drthor

drthor
Irving, TX
(Zone 8a)

March 7, 2013
5:04 AM

Post #9441585

Pfg
will it be the same to add Cinnamon to the water? instead to sprinkle it on the soil?
Pfg
(Pam) Warren, CT
(Zone 5b)

March 7, 2013
6:17 AM

Post #9441662

I don't know. I think I've read hat some people add it to the soil..
DanSt
Bismarck, ND

March 7, 2013
12:38 PM

Post #9441997

I was gone for a while and pleasantly suprised by the number of reponses to the bleach question! Again its a mix of "have used" and "not used" but nobody sounded an alarm about NOT using bleach so I think Im going to use a 10 to 1 mix and wash the trays and since the 9 packs are fairly cheap I think I'll recycle and replace those and reuse the larger cells for potting up.
Pfg
(Pam) Warren, CT
(Zone 5b)

March 7, 2013
12:44 PM

Post #9442005

There's nothing wrong with using it, for sure. We're just all over the place about how necessary it is. So many variables...

Pam
nelsoncastro
Victoria
Australia

March 10, 2013
7:07 PM

Post #9445232

When starting seeds indoors, it is essential that the seed flats and trays are cleaned and disinfected before reuse.

If they are not disinfected properly, seedlings will likely suffer from damping off (which will kill the seedlings at the soil level). This is one of the things that makes starting seeds indoors much more time consuming.

Wipe the loose dirt out of the flats and trays. Next is to wash them in soapy water to remove the hardened on dirt. Then to disinfect them, soak it in a 5 gallon bucket of a water and bleach mix for 15-20 min. Use the recommended 1 part bleach to 9 parts water solution. Finally, rinse them, let them air dry and they are ready to use for starting seeds.
cjbr
Wakita, OK

March 10, 2013
7:25 PM

Post #9445249

We've also had good success with soaking pots and trays in a solution using a commercial sanitizer available at Sam's. It's only about 6 dollars for a large bottle of concentrate and doesn't irritate my asthma like bleach does.
altagardener
Calgary, AB
(Zone 3b)

March 10, 2013
8:50 PM

Post #9445347

nelsoncastro wrote:When starting seeds indoors, it is essential that the seed flats and trays are cleaned and disinfected before reuse.
If they are not disinfected properly, seedlings will likely suffer from damping off (which will kill the seedlings at the soil level).


Well, this is the variability being discussed... I don't find it necessary at all for starting seeds indoors, and it seems others find the same. Evidently, in your conditions, it is necessary. I wonder why?

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 11, 2013
10:19 AM

Post #9445858

For me, the biggest variable seems to be how wet the surface of the soilless mix is, and how 'open' the mix is.

Then, for slow seeds, whether they have been pre-soaked (Salivia)

After that, and I'm guessing now, running a little fan even part of the time seems to help them stay healthy.

Also, if I leave some seedlings in tiny cells TOO LONG (like 72 or 128 cells per tray), nothing can keep them from dieing. But preventing the bottoms of the cells from being waterlogged (with perched water) gives them an extra few days before they die.

blomma

blomma
Wyoming, WY
(Zone 4a)

March 11, 2013
7:41 PM

Post #9446438

Since Nature does not sterilize her ground I don't sterilize my seeding trays. I just wash them as they get emptied. Never had any problems. Can't see making more work for myself when it is not necessary.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 12, 2013
7:29 PM

Post #9447523

>> Never had any problems.

In my mind, that's the key phrase, especially after filling in the subject: YOU don't have a damping-off problem or soil-born diseases. I used to have entire trays of seedlings die, so I use a few of the tricks. Not Clorox or peroxide yet, but I bet many of the people who do, need to, for one reason or an other.

>> Since Nature does not sterilize her ground I don't sterilize my seeding trays.

That, on the other hand, is an argument form with which I respectfully disagree. (Or you might have been rhetorical.)

If I succeeded in duplicating EVERY relevant aspect of nature, it would be more persuasive, but I'll stick with your other argument instead: what works for you, does work for you. What works "for nature", might not work for everyone who starts seeds indoors.

I'm probably not DISagreeing with you, maybe I'm just splitting hairs.

Nature is perfectly happy with 1% germination and 2% survival of seedlings if the plant drops 10,000 seeds.

Nature is perfectly happy if entire varieties and species die off if they c an't hack it in that locale: there's
plenty more species where they came from.

If a spot takes a few dozen generations (or 100 generations) to re-populate, that just provides a niche for new varieties to develop.

Nature seldom treis a warm-season. long-seson crop in a cold, short-summer climate.

Nature usually provides deeper drainage than my 2-3" cells provide.

Nature provides air that moves and isn't stagnant, and smells better than my indoor air!

Nature provides brighter light than I provide

Nature provides an entire population of soil microbes many of which are beneficial.

Nature seldom over-waters as much as I do (a skill I'm sure you and most gardeners have mastered).

(I'm not trying to be contentious, but I hear the suggestion that we should imitate nature more often than I agree with it.)

blomma

blomma
Wyoming, WY
(Zone 4a)

March 12, 2013
7:58 PM

Post #9447557

Well Rick, I will just say this. I have gardened in 4 states, and altogether for 45 years. So, if nothing drastic has happened from not sterilizing in all those years, I don't feel the need to waste time when not needed, I think I am doing fine.

The states that I have gardened in was NY, MA, NE, and now WY. I didn't sterilize in any of them. In all the years I have gardened, I learned what is important and what isn't.

I scrape off any dirt, including lime deposit on pots and trays. Then wash with hose and scrub with SOS, rinse and leave in the sun to dry. I just don't sterilize in bleach or anything else.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 12, 2013
8:28 PM

Post #9447594

I'm pretty sure there is something that you're doing that prevents damping off. If we identified that, and everyone was able to do that successfully, probably no one would need to bleach pots.

I assume that you would agree that many people DO have problems with damping off?

(Hmm, it would be interesting to try to measure whether someone WITH frequent damping off problems had fewer if they started using bleach BUT did everything else the same way they did before. I know that I changed many things my first few years of seed starting, and then picked ONE of the changes as the "reason" I stopped having damping off problems.)

>> leave in the sun to dry

Maybe you're getting UV sterilization ?

More likely, something about the way you water, or provide air circulation, or the seed-starting mixes you use prevent damping off.
Pfg
(Pam) Warren, CT
(Zone 5b)

March 12, 2013
8:48 PM

Post #9447608

Peroxide. No damping off.
altagardener
Calgary, AB
(Zone 3b)

March 12, 2013
10:05 PM

Post #9447661

RickCorey_WA wrote:

>> leave in the sun to dry

Maybe you're getting UV sterilization ?

More likely, something about the way you water, or provide air circulation, or the seed-starting mixes you use prevent damping off.


I don't leave pots in the sun to dry, since I don't wash any pots; I top water; I've never used a fan or anything to promote air circulation; and I use a variety of soil mixes (all starting with commercial potting soil but reused year to year) depending on what I'm growing (border perennials or alpines).
So, go figure...

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 13, 2013
2:38 PM

Post #9448259

Successfully re-using soilless mix from year to year is the most amazing. Do you put some of your own compost into each batch? If you have some potent friendly microbes that prevent damping off, you could sell them and get rich!

I think we need to follow you and blomma around with video-cameras to see what magic thing or things you do that prevent damping off!

I see from PlantFiles that you're also very experienced.

(I assume you meant that you do all those things above, but still DON'T have many or any seedlings lost to damping off. And you don't sprinkle pixie dust o mist with various potions. )

I usually assume that perennials and alpines will be pretty slow-growing for their first few inches, hence most vulnerable to D.O.

I'm going to bookmark your post so I can point other people to it as proof of "on the other hand ..."

P.S. Can I ask how you store seed-starting mix from year to year so you c an re-use it? Do flush it? Does it freeze all the way through?



This message was edited Mar 13, 2013 2:50 PM

This message was edited Mar 13, 2013 2:52 PM

Tammy

Tammy
Barto, PA
(Zone 6b)

March 13, 2013
4:05 PM

Post #9448347

If someone has problems with damping off, it would be interesting for them to run an experiment. Sterilize half the pots and don't the other half. Start same seeds in these and see if there's a difference in damping off. (Obviously water the same & have same airflow over both).

I haven't had any problems with damping off. I sterilize my pots just because... I have a huge double laundry sink so I fill one side, add bleach and soak the pots, swish them clean with a brush, rinse & air dry. But I don't know that it actually makes a difference that I add the bleach. The sink is awfully large so its probably not at the recommended strength and its open a long time with several batches of pots so it probably gets weaker with each batch (yes - I wash A LOT of pots each year).

Tam

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 13, 2013
4:30 PM

Post #9448378

Tammy,

>> I haven't had any problems with damping off. I sterilize my pots just because...
>> But I don't know that it actually makes a difference that I add the bleach.

I bet that describes more than 75% of most people's garden practice and garden advice.

"I always do it this way ... and it works for med."

Once we read 4-5 people saying that, we start telling each other: "we HAVE to do it THIS way ..."

I very seldom be controlled experiments, even though I love to fiddle and play at "making science".

Sometimes I think that our "special tricks" just remind us how careful and virtuous we're being. In my case, maybe it helps me to overwater a little less, and that makes all the difference.

altagardener
Calgary, AB
(Zone 3b)

March 14, 2013
11:54 AM

Post #9449168

RickCorey_WA wrote:Do you put some of your own compost into each batch? P.S. Can I ask how you store seed-starting mix from year to year so you c an re-use it? Do flush it? Does it freeze all the way through?


No, I've never added compost to my soil mixes so there's certainly no "potent friendly microbes" being added. The soil I reuse is just dumped into large Rubbermaid storage bins that are kept in my basement potting area until next usage - no flushing (whatever you may have meant by that?), and no freezing.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
12:11 PM

Post #9449186

>> no flushing (whatever you may have meant by that?),

I usually flush some water through a container "to remove excess salts" or left-over fertilizer. But I guess that seed-starting containers don't get much, if any, fertilizer added.

Something you do must be pretty wonderful if it prevents damping off even while re-using mix and pots from year to year without washing.




altagardener
Calgary, AB
(Zone 3b)

March 14, 2013
12:37 PM

Post #9449213

Tammy wrote:If someone has problems with damping off, it would be interesting for them to run an experiment. Sterilize half the pots and don't the other half. Start same seeds in these and see if there's a difference in damping off. (Obviously water the same & have same airflow over both).


Yes, I agree totally! That would be a great first step towards an actual controlled experiment! Seed-starting advice on these forums and in general suffers, IMO, from a huge lack of scientific reference - people draw hard and fast conclusions from information that is anecodotal. Note: Some information, though it is anecdotal, may be based on a lot of repeated observation and may be sound though it is not based on controlled experimentation. However, I think the vast majority of anecdotal information is not necessarily well-thought-out, and is not based on a lot of knowledge, or experience and observation. For example, a single experience may often be the basis for an opinion that becomes the only possible truth for that person.

On public forums actual scientific evidence (e.g. Dr. Norm Deno's findings) tends to get shouted-down or is simply overwhelmed by the all anecdotal advice. A large part of the anecdotal stuff (though not all) consists of people advising other people to do random things that can't be supported by any chemical or physical reasoning. What I mean by "random" and "insupportable" are various things I've read, e.g. chill seeds in fridge overnight (this was in a published book purporting to tell people how to start seeds), soak seeds in apple cider (Why apple cider, if soaking is the goal, rather than plain water? "Because it's an acid"). One can see how these bits of "advice" probably came from a distortion or misunderstanding of findings from actual studies. I suppose the "overnight in the fridge" bit is some miscomprehension of what stratification is about, and the apple cider bit may be some misunderstanding of what sort of strength of acid would actually be needed to make any difference in dissolving through a hard seedcoat. Anyway, very interesting subject.
altagardener
Calgary, AB
(Zone 3b)

March 14, 2013
12:47 PM

Post #9449229

RickCorey_WA wrote:>> no flushing (whatever you may have meant by that?),

I usually flush some water through a container "to remove excess salts" or left-over fertilizer. But I guess that seed-starting containers don't get much, if any, fertilizer added.

Something you do must be pretty wonderful if it prevents damping off even while re-using mix and pots from year to year without washing.


I use very little fertilizer. I want sturdy, compact plants, not soft, loose ones.

I'm not doing "anything wonderful" - I am doing the absolute minimum!

altagardener
Calgary, AB
(Zone 3b)

March 14, 2013
1:11 PM

Post #9449257

RickCorey_WA wrote:I'm pretty sure there is something that you're doing that prevents damping off.


Maybe it's the other way around... are people doing something that promotes damping-off? E.g. excess watering? If bottom watering, do pots sit in water? Not removing cover as seeds germinate?

This message was edited Mar 14, 2013 1:16 PM

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
2:47 PM

Post #9449420

Yes, that's exactly the kind of thing I mean.

You don't think you're doing anything special, and yet 90% of beginners DO have damping off. Something like 2/3 to 3/4 of experienced gardeners have enough problems with DO that they jump through some hoops to prevent it. Many or most commercial growers sterilize or throw mix and pots away rather than risk re-using them.

(I usually figure that if PROs spend on something, it IS a problem for most people.)

So something or things that you and blomma do, that you don't think are special or noteworthy, ARE giving you results that many people can only achieve by jumping through hoops and spending time, energy and money. If you could bottle it and patent it, you could be rich! Maybe something rare and precious like "common sense"! :-)

"Too much watering" or "too-wet surface" or "humid air" are all highly probable suspects. Everything I read used to say "dirty pots or re-used mix or dirty mix", but now I have to question that wide-spread belief. It does not apply to everyone!

There are many anecdotal reports of "I used to have DO, but now I bottom water and that cured it".
And "I used to, but now I sprinkle grit or Perlite and it stopped".
And "I used to, but now I water with H2Os and it stopped".
And "I used to, but now I sprinkle cinnamon and it stopped".
And "I used to, but now I water with Chamomille tea and it stopped".

In my case, I used to have a lot of DO and non-emergence, but now I do blah blah blah and have never seen it since. I THINK the faster-draining mix and coarse non-water-holding top-dressing and maybe the fan are the cures. But maybe without knowing it, I ALSO learned how to avoid over-watering, and I just don't realize I did?

Maybe it's all about having enough air in the mix. The evidenc e is not c ontrolled enoguh to conclude anything "scientifically".

>> Not removing cover as seeds germinate?

That may cause terrible problems to beginners, but there is such a loud, unanimous online chorus of "take the done off AS SOON AS the first sprout emerges", that I don't think many people make that mistake twice. Not if they go online to ask for advice!

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
2:52 PM

Post #9449424

Altagardener,

>> people draw hard and fast conclusions from information that is anecodotal

>> For example, a single experience may often be the basis for an opinion that becomes the only possible truth for that person.

>> and may be sound

Those were really well said and I agree with all of the above.

I think that MOST gardening advice comes from hearsay and "this worked for me, so it is the best or the only way".

My approach is that if several people I respect say THEY do it a certain way, I'll try to imitate them as a starting point to see if I can find something similar that works for me. Then I either adopt that as My One True Way, or keep doodling with variations that amuse or interest me - or seem cheaper or easier or more fun.

I have the same "My Way" disease that many people have. Once I come up with "My Way", and happen to like it or be proud of it, I'm stuck in that rut for a long time, for good or for ill.

But I don't care if 100 people all quote the same common knowledge. That just means that we all know the same old tales or read the same websites. One person who says I DID THAT knows more than 100 people who read about it.

One person who tried it several different ways and noticed different results under somewhat controlled circumstances knows more than 10 people who "always do it the same way".




This message was edited Mar 14, 2013 2:59 PM

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
2:57 PM

Post #9449426

Probably my silliest gardening habit is that I want things to "make sense to me".

Silly, right? If it works, why should I care WHY it works? I'm not sure, but I want to know "why"! Then maybe I can think up some other way to get the same effect, even better adapted to my conditions and my own preferred habits.

I don't care if "everyone" knows something or does something: if I can't dream up some pseudo-plausible mechanism that explains why it "should" work, I'm suspicious of it. I want to find a different way that "makes sense to me".

Or I want to doodle around with variations on the "thing that makes no sense" (to me) until I see some result that hints at what is really going on. Or it may even work better for me!

Since I seldom put very much effort into real controls, it's Lazy Science or pseudo-science or just pottering around for entertainment.

drthor

drthor
Irving, TX
(Zone 8a)

March 14, 2013
3:06 PM

Post #9449440

ooohhhh i have a big headache my English is not so good to understand all of those words ... oohhh

What if I tell you that I "never" cleaned or sterilized my pots of soil ... I never had any of those problems ...

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
3:18 PM

Post #9449442

I'm not ranting for or against bleach or anything else. The last two posts were just rambling about the intersection between hobby-gardening and the semi-scientific method or pseudo-scientific method ... or the lengths to which I will go in order to entertain myself!

People who use the practical method of "this works for me" and "I avoid unnecessary work" are certainly more practical then I am, and in that sense much smarter.

I suspect that anyone who does large volumes of seed trays may HAVE to give more consideration to "least effort" than I do with my 4-6 trays per year.

As it happens I don't bleach or re-use USED mix. I don't even water seeds with potions or sprinkle with pixie dust (but I keep intending to water with H2O2 'just because it sounds like a good idea'.

I do save UNused mix and bark from year to year under not-very-clean conditions. I always clean seed trays carefully and usually clean bigger pots reasonably well. Why? At one time I thought those were necessary and now they are a habit.

I'm passionate about very fast-draining, very-well-aerated mix, because that's my pet theory. Many other people get good results with peaty mixes and without obsessing as much as I do: some day if I get tired of pine bark I may evolve in their direction.

And every time I set up a tray and every time I water or refrain from watering, I think about whether I'm still over-watering and argue with myself about it. Probably that is where I should focus my attention, but I've chanted "moist but not soggy" and "damp but not moist" ... or is it "moist but not damp" until I'm dizzy.

My new mantra is "just barely NOT DRY".

Or I'll make up a Charles Goren Box for watering. There's a joke that Goren had a secret box that told him how to bid. After he died, people were allowed to look into the box. It had one piece of paper with one word on it. "PASS".

My Watering Box would say "DON'T water yet".

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
3:24 PM

Post #9449445

Drthor, that is the topic of the thread.

I'm glad the three of you are chiming in with "I don't need to do anything special". Something like 70% of seed-starting people had trouble with damping off until they found some "trick".

I wish you (you three) knew what it was that you're doing that prevents the problem, and could teach it to me, and to professionals who currently spend a lot on steam, bleach and new pots every year.

It might be as simple as "moist but not damp". Or being able to sense that these seedlings would wilt in another 24 hours so I WILL water today instead of three days ago.
trc65
Galesburg, IL

March 14, 2013
8:43 PM

Post #9449799

altagardener wrote:

Yes, I agree totally! That would be a great first step towards an actual controlled experiment! Seed-starting advice on these forums and in general suffers, IMO, from a huge lack of scientific reference - people draw hard and fast conclusions from information that is anecodotal. Note: Some information, though it is anecdotal, may be based on a lot of repeated observation and may be sound though it is not based on controlled experimentation. However, I think the vast majority of anecdotal information is not necessarily well-thought-out, and is not based on a lot of knowledge, or experience and observation. For example, a single experience may often be the basis for an opinion that becomes the only possible truth for that person.

On public forums actual scientific evidence (e.g. Dr. Norm Deno's findings) tends to get shouted-down or is simply overwhelmed by the all anecdotal advice. A large part of the anecdotal stuff (though not all) consists of people advising other people to do random things that can't be supported by any chemical or physical reasoning. What I mean by "random" and "insupportable" are various things I've read, e.g. chill seeds in fridge overnight (this was in a published book purporting to tell people how to start seeds), soak seeds in apple cider (Why apple cider, if soaking is the goal, rather than plain water? "Because it's an acid"). One can see how these bits of "advice" probably came from a distortion or misunderstanding of findings from actual studies. I suppose the "overnight in the fridge" bit is some miscomprehension of what stratification is about, and the apple cider bit may be some misunderstanding of what sort of strength of acid would actually be needed to make any difference in dissolving through a hard seedcoat. Anyway, very interesting subject.


Very well said, Thank You!

You point out the reason I've come to this forum less and less. I've gotten frustrated with everyone giving recommendations with no scientific evidence (or a grounding in reality). I used to spend the time to try and correct misinformation while offering scientific based explanations and recommendations, but I don't have time for that anymore.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 14, 2013
9:34 PM

Post #9449822

Just to offer an "on the other hand", and "take the other side", several people have cited studies that were done scientifically, showing something specific about supplying bottom heat to germinating certain seeds providing no benefit (under certain specific conditions and defining "no benefit" in a precise and specific way that was easy for them to measure).

Then those studiers were translated or mistranslated into something like "no one should ever use bottom heat because it never has any advantage of any sort to anyone".

The overwhelming evidence to the contrary (contradicting the mistranslation, not the study) may be anecdotal because it was not obtained or documented under tightly controlled conditions and then peer-reviewed. But there is a difference between "anecdotal" and "useless". The determining factors are HOW sloppy our "before and after" tests are and how much they came from "I did this", and how much they came from pass-along hearsay.

I would also argue that there is more value to thousands of people doing something and forming an opinion, than there is in a dozen people doing it.

I also use a "plausibility" test.
- Seeds germinate and emerge faster at different soil temperatures.
- A seed catalog or an Ag text shows many or most seeds' optimum germination temperature over 70F.
- Some seeds' optimum germination temperature is above 80 or even 85 F.
- Slow seedlings straining to overcome adverse conditions may be more subject to diseases and (anecdotally) don't always recover and "catch up" from early stresses.
- Most commercial growers spend money and energy to control germination temperatures, and they aren't stupid or knowingly wasteful.

The ultimate benefit of a germination heat mat may be subtle, or only accrue to some gardeners, or only observed outside of ideal lab conditions, but this is one case where I trust the large % of gardeners who think heat mats improve their results, over the [u]applicability and relevance[/u] of loosely quoted studies that found one set of circumstances where one specific metric was not improved by the use of a heat mat.

Or consider a thought experiment.

The seed starting room air temp is 55-60 F.
The seeds are peppers and eggplants.
Optimum germination for them is above 85F.

At 55 degrees or less (soil is usually colder than air, at least indoors) , will they come up in time for summer, or ever (before they rot), or before the cat knocks the tray over?

Or will they struggle to the surface and succumb to damping off or TMV or aphids before they're 3" tall?

This is just an "on the other hand" suggestion. I value the results that come from controlled experimentation, but the value of science is not in one or another study, but rather in the accumulated consensus of dozens of studies that agree.

it's also important to find and define the areas of relevance of any one study's conclusion. That's usually advanced by one research team "showing up" another team by finding an exception to their rule, or varying some previously un-thought-of condition that reverses some aspect of the first team's conclusions.

The PhD version of "Naah Naah Nye Naah Naah, so THERE!". Now that's Real Science!
birder17
Jackson, MO
(Zone 6b)

March 15, 2013
9:34 AM

Post #9450317

Kindness please.
altagardener
Calgary, AB
(Zone 3b)

March 15, 2013
10:10 AM

Post #9450339

RickCorey_WA wrote:
The ultimate benefit of a germination heat mat may be subtle, or only accrue to some gardeners, or only observed outside of ideal lab conditions, but this is one case where I trust the large % of gardeners who think heat mats improve their results, over the [u]applicability and relevance[/u] of loosely quoted studies that found one set of circumstances where one specific metric was not improved by the use of a heat mat.

Sorry, it's difficult to understand your logic here... It's not sensible to support scientific controlled studies on one hand, but then to throw them out on the other hand by presuming that they're only valid in some sort of "ideal lab conditions".
If you haven't done so, I'd suggest you read Deno's publications - which are easily accessed these days - and also Henry M. Cathey's 1969 publications in Florist's Review on heat mats if you can find them (and if you do find them, please let me know how). (Deno summarizes Cathey's findings.)

This message was edited Mar 15, 2013 11:19 AM

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 15, 2013
8:48 PM

Post #9450921

I'm not trying to be contentious or arbitrary.

The main reason I question this result and not some others, is that real-world experience by pros and many careful hobbyists flatly contradicts what was alleged as someone's conclusions about laboratory-controlled situation.

The mis-quoters aroused my ire. Just changing "usually" to "always" and then sneering at the entire gardening and agricultural population as superstitious dullards got me going. (That was some other thread, in a forum far away and long ago.)

I'm curious to know what Cathey actually tested, and whether tomatoes, peppers and eggplants germinate and emerge just as fast at 70 as 80-85.)

Also I know Deno worked with small numbers of mostly-esoteric seeds, mostly ornamentals and wild seeds. (Plus he states that he tested at 40 and 70F, not above 70). I thought he tested hardly any common garden crops, but apparently he must have tested some (at 70).

I found it!

SEED GERMINATION THEORY AND PRACTICE SECOND EDITION
pp. 3-4 in the Second supplement

Deno said:
"Secondly, a century ago temperatures inside houses were colder than the 70 which is now customary. In such colder houses bottom heat was beneficial in order to raise the temperature to 70."

First, everything said there SUPPORTED the idea that 70F is needed by many seeds to get even "satisfactory" germination. Greenhouses, basements and bedrooms BELOW 70 F usually or often benefit from germination bottom heat. That could be the end of the debate from my perspective.

My original objection stands: misquoting a scientist who made some SPECIFIC claims based on specific controlled tests into "ALL you people are dumb for ever using heat mats" is a misuse of the empirical method.

(It is also often hard to extrapolate from a lab into the real world. You have to allow for the different conditions and expectations. Deno's "satisfactory" might be someone else's going out of business due to increased heating costs or slow germination.)


I read what Dr. Deno said as "I have studied germination at 40 and 70 for most of the species studied by Cathey and confirm that germination at 70 is satisfactory."

So he did not test warm-weather crops above 70 himself.

What was "satisfactory" to him, with small numbers of seeds in sterile paper towels may not have been "optimum" compared to many thousands of gardeners and market growers and nursery people starting millions of trays of seeds.

He cited Cathey's data (or conclusions) as :
"Germination was usually optimum around 70, and temperatures down to 50 or up to 85 often result in markedly lower germination."

"Usually" and "often" are not "always" and "never". If they are saying that "most" seeds don't need bottom heat in a 70F room, well, duhh, yeah.

I need to look at the specifics of Cathey's tests, criteria and data to say anything more. But also, from the time I spent doing tissue culture and cancer research, I know that I need to ask myself what axes Cathey and his/her team were grinding. What have they been trying to convince others of, for the last 10 years? Every scientific paper (every text of every sort) is written by someone with opinions, motivations and biases that might be conscious or unconscious. Cathey might be a saint, or might be a normal scientist (normal human).

The example I use is the study funded by the National Peat Association (something like that). They showed much worse seedlings did (in their lab, in their tests), with coir instead of Wonderful Peat. If you read carefully enough, you might notice they never washed the coir and bought it "wherever". Then if you read another graph carefully, you might tell yourself "LOOK at all that frigging SALT!!". Duhh, yeah, the seedlings barely survived the terrible choice of the coir supplier." But their conclusion was not "flush the coir if you buy a bad batch", it was "seeds germinate MUCH better in our product than in coir. Coir stinks and no one should use it".

More likely, Deno and Cathey both found something "satisfactory" because the species and conditions they were most interested in, and their criteria for success, agreed with their conclusions, not someone else's real-world needs. Like air temperatures below 70, or below 85.

= = =

It's more interesting that these two concluded that "everyone else is wrong" about any crop seeds benefiting from soil temps above 70. (Or did they claim "usually" and "often", for most species, instead of "any"?)

Deno states that he (Deno) tested at 40 and 70, as I thought, yet then makes this claim:

>> "Both Cathey's results and my own indicate that temperatures above 70 are neither necessary or desirable for germination."

Maybe they did not desire fast germination! Deno seems to find germination after 6 or 10 weeks just fine, but I think nurseries prefer 6-10 days if they can get that with a little bottom heat.

I'll need to find and look at Cathey's data to see how many hot-weather crops he or she tested. Also, I would need to find the rationale behind "not desirable". If they don't care about speed of germination, or are talking about situations irrelevant to the people who have extensive experience with bottom heat working better for them, that would explain the disconnect.


I was trying to make some distinctions:

- Carelessly repeating hearsay without asking "how many people TRIED it both ways" is bad.

- Giving some consideration to an observation made by thousands of professionals on millions of seed trays over many decades and at least some careful hobbyists is good.

- Reading one or two studies and then claiming they proved wildly more than they ever tested is bad.

- Reading any number of studies and then drawing b road conclusions without citing the limitations of each study doesn't get any traction in scientific circles and shouldn't from uis, either.

Concluding much of anything based on 1-2 studies is actually very bad. Technical literature is FULL of studies (and years worth of repeated studies) that were then contradicted (or explained) by later studies that said in effect "but what about THIS variable??"

Like noticing that the Phosphate concentration in the buffer had a huge unanticipated effect on tissue culture growth, when five years of smart PhDs all thought "Oh, that just controls the pH, we always use PBS". Switching from Phosphate Buffered Saline to Ringer's solution or Ringer's Lactate could give TOTALLY different results about blah-blah-blah cellular interaction. They weren't lying or even wrong just irrelevant to what they thought they were studying (conditions inside HUMAN tissues).

The real world is complicated. Lab research is hard. Applying lab reults to the real world is REALLY hard.

When a few studies contradict huge amounts of carefully-collected real-world experience, maybe a few more studies are needed. Maybe they should go into commercial greenhouses in Alaska and try to start 10,000 tomato seedlings at minimum cost. When they tell the owner "now dial your air temp up to 70 F +/- 1 F", maybe their research funding will pay for the new heaters and all that oil.

Not that I know how Cathey did his or her tests, or what factors I would ask to be re-checked by independent teams.

But the real world is much more complicated than any lab. No one can test EVERY variable or even reliably think of all the relevant variables.

Or maybe both Deno and Cathey were exasperated by stupid people who thought that EVERY seed needs as much warmth as eggplants and peppers.

More likely they knew how to avoid ever damping off, drying out, aphids, cold drafts, mites, intermittent over or underwatering. Or cats that will pee in a pot if the seedlings don't come up pretty quickly. If it was a variable that they didn't test, that "laypeople" don't control perfectly, lab results are just not relevant to real world "laypeople" until enough different te4ams te4st the same theory in different ways to stumble onto the RELEVANT real world issues (molds, fungi, drafts, underwatered weekends, cats ... ).

Or maybe I'm wrong, and nurseries and greenhouses DO heat huge glass structures to 70, or let acres of seed trays sit around for three times longer than necessary, waiting for seeds to sprout.

Or maybe every resource I've seen that cites optimum germination temperatures for many crops are just untested superstition. I need to buy some Ag textbooks before I go too far down that road, just because some superstitious bumpkins start some crops indoors with heat.

Possibly I'm even wrong about peppers and eggplants germinating faster at 80 or even 85 than at 70. I thought those were no-one-would-argue examples.


Since Dr. Deno put all three into the public domain, I'll assume his permission to quote.

"Henry M. Cathey has already studied this question extensively, and his results were published in Florist's Review August 21, August 28, and September 4, 1969. He studied germination at five degree intervals from 50-85 F. Germination was usually optimum around 70, and temperatures down to 50 or up to 85 often result in markedly lower germination. I have studied germination at 40 and 70 for most of the species studied by Cathey and confirm that germination at 70 is satisfactory.
...
Both Cathey's results and my own indicate that temperatures above 70 are
neither necesary or desirable for germination.
...
Why have temperatures above 70 have been recommended so often? Many of
the recommendations in the literature are inferential such as recommendations to use
heating cables or place the seed flats on hot pads or other warm surfaces such as the top of a refrigerator. There are possibly two reasons for these traditional concepts. Many greenhouses in spring may be at temperatures significantly below 70 and particularly the soil temperatures are below 70. Bottom heat could be helpful.

Secondly, a century ago temperatures inside houses were colder than the 70 which is now customary. In such colder houses bottom heat was beneficial in order to raise the temperature to 70."

P.S.

Persistent URLs for Dr. Deno's book
"Seed Germination, Theory And Practice"
and supplements:

http://hdl.handle.net/10113/41278 (1993)
http://hdl.handle.net/10113/41279 (1996)
http://hdl.handle.net/10113/41277 (1998)

(I think six pages is my longest forum post ever!
Apologies to anyone wearing out their "page Down" key!)


This message was edited Mar 15, 2013 9:10 PM

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 15, 2013
9:08 PM

Post #9450929

P.S. I'm not making my main point up. Here's a list from Thompson & Morgan.
I skipped over anything whose lower limit for recommended germn soil temp was below 75, then only scanned A+B+C.

Abelmoschus - - - - 75-80
Araujia - - - - 75-80
Aristolochia - - - - 75-80
Cacti - - - - 75-80
Caesalonia - - - 75-80
Cordyline - - - 75-80
Crossandra - - - 75-85

But spank me, they cite 70-80 for tomatoes!
Solanum 70-80


http://tomclothier.hort.net/page11.html

Tom Clothier is respectable and not a seed vendor.
He cites 86 F as fastest emergence for eggplants, Cucumber, Muskmelon, Okra,

He cites 77F as optimum (fastest) for tomatoes, peppers and many others:

Johnnies Seeds cites similar optimums, many above 70F.

Asparagus, lima beans, snap Beans, Beets,
Cabbage, Carrots, Cauliflower, Lettuce,
Peas, Peppers, Radish, Sweet Corn, Tomatoes and Turnips.

If Deno and Cathey are just saying that no one should care about fast or slow germination, OK, they have free speech too.
trc65
Galesburg, IL

March 15, 2013
11:26 PM

Post #9450964

And those last two posts illustrate the other reason I spend very little time on this forum (or site). Long ranting posts that are way off topic. I've come to the conclusion that there are only about 10 people here who actually know how to create a thread and everyone else chimes in to discuss anything that pops into their mind.

It also reminds me of my days as an Extension Specialist when someone would come it with a "terrible problem" and "desperately needed my help" I'd take time, research a solution for them and talk them through it - they would then spend the next half hour telling me I was wrong and didn't know what I was talking about because Aunt Sal told them to do something her Aunt told her about when she was a kid. It was frustrating then and even more so now.


Bye
Debsroots
Northwest, MO
(Zone 5a)

March 16, 2013
5:16 AM

Post #9451039

I agree...this is becoming ridiculous ...please just stop :(

blomma

blomma
Wyoming, WY
(Zone 4a)

March 16, 2013
5:53 AM

Post #9451060

trc65, Debsroot
I agree 110%.
birder17
Jackson, MO
(Zone 6b)

March 16, 2013
6:32 AM

Post #9451086

Spring FEVER!!
Pfg
(Pam) Warren, CT
(Zone 5b)

March 16, 2013
7:36 AM

Post #9451173

I also agree wholeheartedly.
Zen_Man
Ottawa, KS
(Zone 5b)

March 16, 2013
10:00 AM

Post #9451297

I personally enjoyed reading Corey's long messages, and although I might not agree with everything he said, I appreciate that he took the time and effort to put that information and those viewpoints here. My guess is that, right about now, he is reminded of that old saying, "No good deed shall go unpunished."

I also appreciate the information and viewpoints provided by other responders. We have strayed from the original topic of "To Bleach or Not to Bleach?" and that is still an open question, as it probably should be.

RickCorey_WA

RickCorey_WA
Everett, WA
(Zone 8a)

March 18, 2013
11:24 AM

Post #9453599

It always puzzles me that a long post bothers anyone. With the Page Down key, it takes less than 2 seconds to scroll past the longest post, But it takes 10 times as much work to say "I don't like the way you post".

Still, many6 people feel strongly about thread drift, so I'll defer to the wishes expressed above.

I guess I don;'t always wait for the original topic to peter out before I drift off-topic, but no amount of thread drift ever prevents anyone from saying anything they have to say on the original topic .

If altagardener, with whom I was speaking, wants to continue, we can do it by private Dmail.

Thanks, Zen-Man .
DanSt
Bismarck, ND

April 8, 2013
2:22 PM

Post #9476389

Its been awhile since I visited this question I first posted in Feb. I didn't sterilize, just washed with warm/hot water, allowed them to drip dry and reused them So far all my seedlings look good. I have four 72 cells trays and two 18 cells trays of toms, peppers, onion, broccoli, etc. We'll see and I'll report back. Hopefully I didn't screw up by not heeding trc65s advice. Also I didn't realize that damping off was anyway related to bleaching my stuff. Guess you learn something new everyday.

blomma

blomma
Wyoming, WY
(Zone 4a)

April 8, 2013
3:05 PM

Post #9476444

Here are my seedllings growing in 6-packs and 3" pots that have only been washed and airdried. No sterilization and no damping off...ever!

1] Daylilies in 6-packs March 23, 2013 and not one died from dampingoff.
2] Closeup
3] Daylilies in 3" pots that have not been sterilized and not one.
4] 156 Daylily seedlings in the nursery on May 2012
5] Dayliliy seeds sprouting with Deno method just prior to planting in 6-pack. This may be the reason why no damping off.

Thumbnail by blomma   Thumbnail by blomma   Thumbnail by blomma   Thumbnail by blomma   Thumbnail by blomma
Click an image for an enlarged view.

DanSt
Bismarck, ND

April 8, 2013
3:58 PM

Post #9476512

Thanks blomma. Makes me have hope for my choice! I'll google "Deno method".

blomma

blomma
Wyoming, WY
(Zone 4a)

April 8, 2013
6:13 PM

Post #9476686

DanSt wrote:Thanks blomma. Makes me have hope for my choice! I'll google "Deno method".


You are welcome.

You don't have to Google Deno. It is just to soak the seeds overnight in hand hot water to plump them up and soften the seed cover. Then place in a moist paper towel inserted in a ziplock bag. If perennials need stratification (moist cold) , place in fridge for 2 weeks. If not, place in room temp.

By the way, I have trays that were purchased in 2002 and after a cleaning, I reuse them to hold pots.





This message was edited Apr 8, 2013 6:15 PM

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