I am a terrible seed gardener!

Fort Dodge, IA

I was growing seed for the 1st time in those little peat pot things you can buy. Things were growing really well and I got excited and bought another plastic planter thing. This one where you add the soil to the little pots and keep the lid on to keep things warm and moist. Things were growing in both pots, looked great one day, went down the next morning and everything was yellow and laying over. I had been growing them in the containers in non direct sunlight, I think they got to wet from condensation??? Basically everything is now dead except three straggly week looking plants.

I am having better luck with direct sewing but some of the seeds I have only a few of and I really wanted to grow and transplant them. Any tips as to what I am doing wrong? Should I not be leaving the hoods on if they are outside once they start to grow?

Please help this total newbie wanta be seed grower.

Ottawa, KS(Zone 5b)

Hi dcartphoto,

"Should I not be leaving the hoods on if they are outside once they start to grow? "

If by "hoods", you are referring to transparent humidity domes, then, yes, you should remove the humidity dome as soon as the seedlings emerge. In the sun, heat builds up under humidity domes a little like heat builds up in a closed car in the sun. The humidity domes are meant to keep your growing medium from drying out until the seedlings emerge. If you wanted to repeatedly sprinkle your starting medium with water to keep it moist, you could do without the domes.

Also, it would help if you included photos, because some of the phrases you use, like "little peat pot things" and "plastic planter thing", are a little bit vague. Photos can be helpful.


Northeast, PA(Zone 6b)

I hate those peat pots! Your story reminds me of my first experience trying seed germination 20yrs ago. Left the dome on the seed tray and put it outside. Baked those puppies and good.


Everett, WA(Zone 8a)

Once sedlings emerge, huimidity is their enemy, and "damping off" is a quick killer. Ask sopmeone qwho tends to overwater how many seeds they've killed, and it will be about as many traysfull as he has room for!

Remove the clear plastic dome ASAP.

If you wnat to keep art of the tray humid wiothout killing the emerged seedlings, you can drape Saran Wrap over just part of the tray. Remove that, too, as soon as sedlings start coming up.

Peat pellets and peat-based commercial seed-starting mix always seem much too soggy to me! They hold so much wtaer that no air can get in. Without air, roots drown and die. At least add pelite or grit to mostcommercial seed-start kixes, unless you know the secret to avoid over-watering. I suppose in theory it would be something like "add less water" but I can NEVER master that.

Instead I make my soiless mix mix so coarse that it drains adequately. When I add too much water, it drains out the bottom. Notice I say "when", not "if".

The surface dries quickly, making damping off less likely. I have not had ANY damping off die-offs since I went to screened pine bark plus grit plus a LITTLE powdery commerical mix.

Galesburg, IL

In addition to the good comments already posted, I think another real problem was light. Indirect sunlight does not provide enough light for developing seedlings. The need supplemental light and lots of it. It is pretty standard to use florescent lights to provide that light. You can use either 2 or 4 ft lights and a 2 bulb light is just about the right width for a standard tray (as long as you rotate the plants in the tray periodically). Standard cool white bulbs are just fine for seedling growth although some people will use 1 cool white bulb and 1 warm colored bulb together. The seedlings should be placed within 6 inches of the lights (closer is better, but then you lose coverage in width). They should be on for about 16 hours a day as duration of light is important when light intensity is lower.

Another possible contributing factor in your plants demise is fertilizer (or lack of it) I start fertilizing with a water soluble fertilizer at 1/4 strength when the first true leaves start developing. I will water with the fertilizer at least once a week until transplanting.

Fort Dodge, IA

Thank you all so much for your responses. I'm going out tomorrow to find pelite or grit, can I get that at a big box store? I'll also take the plastic dome off the seeds as soon as they start coming up. Thank you, thank you. I have lots of "easy" seeds to try. Someone sent me morning glorys, they are pretty hard to kill right. Maybe they can help get me over the learning curve. :)

Calgary, Canada

Don't feel bad as we all make mistakes as we are learning to do something new.
The more seeds that you try to germinate, the better you will become as a gardener!
Keep on trying!

Everett, WA(Zone 8a)

Coarse Perlite will probably be easiest to find.

I only found #2 chicken grit (crushed granite) at a co-op or "feed store". That was a 50-KG bag (over 1 cubic foot) for around $11. They also sold a 2-quart bag of the same grit for $10!

Probably the "best" way to get grit is from a gravel yard, double-screened, no dust and little sand. Just grit around 1/8" (fairly low % below 1/16"). But they will want to sell you a cubic yard for much $$$.

The only way I got clean screened pine bark was to b uiy the best quality "medium mulch" I could find and then screen it myself. I've heard that really good nurseries or nursery supply houses may sell "double-screened pine barfk" ... and charge more. ":Orchid bark" is VERY expensive and much too coarse for seeds.

One downside I did not mention of grit and bark: they may be clean, but won't be sterile. "Sterile" seed-start mix is nice. But HOW nice? Water, air, pots, seeds and trays are not sterile!

I nerver worry about that. I even use a bag of my mix that hazs been sitting around for 10-12 minths, and "everyone" says not to do that. However, in my over-watering hands, damping off is caused by excess dampness, not by dirty soil mix.

Your experiences may differ.

But you CAN get pretty sterile Perlite.

Northeast, PA(Zone 6b)

OK - here's my #1 tip. Use a fan over your seedlings. Works wonders for all sorts of problems.


Galesburg, IL

"However, in my over-watering hands, damping off is caused by excess dampness, not by dirty soil mix."

That's not quite accurate. For any disease to occur you need three things (Disease Triangle): First is a susceptible host- which you have with a young tender seedling, Second is conditions favoring disease development - over watering/favorable temps, Third you need a pathogen - the various damping off pathogens. If you only have two of the three you will not have disease.

Damping off organisms are soil borne, not air borne. If you sterilize your pots, trays etc and you start with sterile soil you have removed a large potential for damping off. Sterilizing pots/trays is easy, fill a large plastic trash can with pots/ water and bleach and let it sit for a couple of hours. Most commercial soil mixes are relatively sterile (from plant pathogens), if you have things you are going to add to mixes, put them on a cookie tray and bake them in the oven. Using the same pots/trays year to year without sterilizing is almost guaranteeing you will have disease problems as the pathogens lay dormant on dirty surfaces of the pots.

BTW, the fuzzy mold you see on the surface of wet pots is not plant pathogenic. It is merely adventitious mold that occurs from airborne spores.

Everett, WA(Zone 8a)

>> Damping off organisms are soil borne, not air borne.

OK, that is news to me. I thought spores were "everywhere", like air, dust, seeds, fingers and tap water.

Your point is well taken that I only need to worry about PLANT pathogens and their spores, not every bacterium and fungus and yeast.

I remember grade school experiments like Pasteur's, where any kind of organic thing at all, with water, rapidly explodes into stinky gunk if exposed to air. From high school and college, I know how hard it is to get ANYthing sterile, and keep it that way.

So I focus on the "conditions" side of the tirangle, and try to keep humidity down. I agree with Tammy that a fan helps a lot. (I assume that is through reducing humidity, but that's a guess.)

Exposure to sunlight (UV) is probably good.

BTW, a fast-growing and helathy seedling helps a lot to reduce the "susceptibility" side. It spends fewer days as a vulnerable baby. Random stresses like insufficient light, excess nutrients, hypoxic or anaerobic soil, too-small root zone, cold, heat ... all those increase vulnerability to stem rot (I believe).

I always clean pots, trays and inserts thoroughly with a hose on "mist" or "spray", then with soap , usually expose them to sunlight for days after the soil is off, and then clean them again to remove dust & wind-borne spores. But I have not used bleach or hydrogen peroxide on the pots (just some seeds).

I like the thinking of people who add products with mycorrhizae (sp?) and other, allegedly beneficial microbes. But I haven't splurged on those yet myself. I've read that roots need SOIL, not soilless mix, to support mycorrhizae. And there are so many different root-fungi , how can any one commercial product contain every variety needed by every plant spoecies?

(Pam) Warren, CT(Zone 5b)

When I started using peroxide in the water I use for everything including wetting the soil before planting, I stopped having damping off problems. And I use self-watering trays with capillary matting on platforms, so there is always standing water underneath my seedlings.



Thumbnail by Pfg
Northeast, PA(Zone 6b)

I don't have any damping off issues but I don't cover my seed pots. And I reuse my pots - soak them in diluted bleach.

I have not tried peroxide though there are a lot of fans here on DG.


Chevy Chase, MD(Zone 7a)

Rick (and anyone else who is willing to chime in): What formula do you use for your seed starting mix? I am planning to start some seeds in the next few weeks.

And is it better to leave the trays of planted seeds outside in the heat (but in the shade), or should I start them indoors?

Ottawa, KS(Zone 5b)


I use Premier ProMix BX to which I add some additional Perlite for better drainage. I wouldn't leave trays outside, because of the possibility that some animal (dog, possum, raccoon, cat, squirrel, etc) might bother them.


Chevy Chase, MD(Zone 7a)

Thanks, Zen. I'm thinking of using a soil-less mix, but I do like Pro-Mix.

Northeast, PA(Zone 6b)

I would call Pro-Mix a soiless mix. I definitely like Pro-Mix but have used many different brands of seed starter successfully as well. I add lots of chicken grit when I'm starting my alpine seeds.

On setting outside - they can get splashed out by rain if uncovered and over heat if covered. I prefer to start seeds indoors under lights and then set out in my greenhouse or deck when they need more light.


Everett, WA(Zone 8a)

I never bought a good or expensive pottin g m ix or seed-starting mix. I have bought bad cheap ones!

My rule of thumb right now is simple: lots of screened pine bark taken from clean, relatively dry mulch.
A little grit, like 5-15%.
Plus whatever you like, and it is probably true that a LITTLE commercial peat or peat mix helps with wicking, as long as it is not powdery and fine, and as long as you add no more than 5-10%.

I like a very open, airy mix. If you have more normal preferences, and you don't have Over Watering Syndrome, you might turn that ratio around:
- Start with a really good commercial mix (anything that has little or no powdered peat or fines)
- Add 20-80% screened pine bark, starting from clean dry "medium coarse mulch".
- Add grit to taste. Or coarse Perlite if you have money to spare.

Avoid wet or smelly mulch - it is fermenting anerobically and why bother flushing & airing it out?

Very coarse Perlite helps drainage and aeration even more, but is expensive, so I use litle or none.

Coarse vermiculite is also expensive and increases water retention AND iot breaks down to powder if you speak harshly to it. I use none IN the mix. But if I sow tiny seeds on the surface,a nd the4y need light, I scatter a thin layer of vermiculite (coarse and/or medium) on the surface of each cell and sow on the surface of that. Otherwise, small seeds fall into cracks between bark shreds and are never seen again. I had zero spouts in 128 cells with petunias one year.

Instead I screen harder with 1/4" mesh to remove as many pine bark "fines" as I can. I would rather put very very little small stuff into my seedling mix, just because I tend to over-water and I LIKE to spray or water my trays every day or two.

ANYTHING that passes through 1/4" hardware cloth, I discard from my "mix" and instead turn under the clayey soil in my outdoor raised beds. There it is very welcome, and helps the clay stay "fluffed up" instead of collapsing into airless pudding. In a coarse potting or seedling mix, the fines just plug up the air channels I want, and retain more water, whcih I do NOT want.

If I had 3/8" mesh, or 1/3" mesh, I would probably discard even more bark fines. What would be going too far in throwing away small bark? If it held so little water that you had to water twice per day.

I don't add "coarse" sand because I never found a bag with less than 50% fines. I don't want no stinking fine sand!

I love #2 chicken grit (sharp crushed granite, screened and washed and maybe sprinkled with fairy dust). I wish I c ould test tgurkey grit some year. If you can get sharp, irregular, double-screened crushed rock, 2-5 mm grains, that would be about the same thing. I want some grians small enough to nestle between shreds and into split bark shreds, plus some big enough to act like bowling balls holding longer shreds wide apart. Maybe it only "needs" 5-10%, but I like 10-15%.

Everett, WA(Zone 8a)

Screened how? This post is how I try to set the UPPER size limit. Think of "fine orchid bark", but even finer, and around 1/10th the price.

If it doesn't pass through 1/2" mesh, it might be too big for your seed-starting cells, cups or pots. And if you sow in flatgs, long shreds of bark might be worse than roots for entagling seedlings with each other, maiing pricking out harder.

Otherwise, keep anything 1/2 to 4 mm in the thinnest dimension, and short enoguh to fit in your cells. More coarse stuff is good! You are likely to find more "fine stuff" and "powder" than "coarse stuff" in the bag of mulch you buy.

So keep anything that passes through 1/2" mesh.

If something doesn't pass through the 1/2" mesh, I usually toss the biggest chunks by hand and re-screen what's left, to see if I can find the smaller bits and still use them. The too-big discards make good outdoor mulch, or you can chop them up and re-screen them.

Roots need air even more thaqn they need water. They drown faster than leaves wilt. And leaves RECOVER from wilt, while dead roots and dead root hairs stay dead.

Everett, WA(Zone 8a)

Here si how I set the lower size limit. I wish I had 3-per-inch hardware cloth, because 1/4" is too fine.

First, anything that passes through 1/4" screen is too small. You can set that seive horizontal and rub the mulch with the back of a steel rake repeatedly, trying to rmeove as much powder as you can. Un less you're infinitley patient, if you can force it through1/4" screen, it's too small.

But that takes time, and 1/4" screen still retains shreds bigger than is ideal. The smaller stuff plugs up the air gaps you are trying to create.

Usually I will try tricks with 1/2" mesh to QUICKLY get rid of or preferentially remove some of the smaller stuff tjhat is, mostly, willing to go through 1/2" mesh. Since bark shreds are very irregular in size, every time you sift, a different set of shreds passes through.

I set the sieve on a 30-45 degree angle and dribble bark down it from the top. The bark should not run RIGHT off, you should move it around with the back of a rake or your hands so that longedr shreds TEND to roll down, and smaller shreds TEND to sift through.

I play with that, keeping or re-screening what stays on top, and discarding or re-screening what passes through. Eventually it gets late or dark, and I stop playing with the screens, mix it with other stuff, and put the finished mix back into the 2-cubic foot bags that the mulch came in .

One cubic foot is 7.5 gallons, but I rely on rules of thumb:
5-10% is "very little"
15% is "a small amount"
25% is "a bunch, but not lots"

When doen, if it isn;t open "enough" or airy "enough", I add coarser bark shreds and wish I had screened out and discarded more fines before I mixed the grit in! As Al has pointed out and explained, you can't make a fine mix open by adding coarse stuff, unless you add something like 2-3 times as much colrase stuff as you started with. You can only make a fine mix grain faster by REMOVING the fines.

They say you should make fresh mix every year and "they" are probably right. Stertile would be nice, but clean is important. I was too busy to start seeds this year, and have been using my mix as classy potting soil instead. But I had planned to use year-old seedling mix kept dry and cleanish in big plastic bags. I might have broken my record of "zero damping off since I drank the pine bark Kool-Aid.

I screen from one wheelbarrow to another so I stoop less, or let the bark roll down an inclined screen onto a clean driveway or a tarp. I use a clean shovel and rake. I have a scoop I made from a heavy jug of laundry detergent - cut off the bottom and use the hadnle as a handle.

Home Depot bark mulch tends to be filthy logyard waste: dirt, pebbles, sticks, trash and probably weed seeds. Plus it sits in the rain, soaks up water, and ferments anerobically or in hypoxic conditions. Alchol, organic acids, aldehydes and ketones can build up, which are all toxic to roots hiars if there's enough of them.

If you buy a few bags of junkl like that, I suggest usin g it as ugly mulch or turning it into a compost heap or directly into soil that will be well-rained on a few times before you plant in it. Or you could de-toxify it - spread it out somewhere it can drain, flush it well a few times, let it dry and then air out. But it was dirty even before you let it sit aorund flsuhing toxuins, so how b adly do you wnat to start seeds in it?

I splurged on 4 cubic feet of GOOD bark mulch - $7-8 per 2 cubic foot bag. Get medium or medium-coarse grade. I prefer long thin shreds to rounded chunks or powder. Evfen if ikt is too coarse, you will p;ay for less powder that takes hours to screen out. Whatever is TOO big to use, use as mulch or you can chop it finer with a sharp hoe or Chinese cleaver, or grater, or food processor. The problem with a lawn mower or chipper-shredder is that you will get the bark dirty, which is not ideal for fussy seeds. OK for vigorous veggie seeds, since bark minimizes damping off. Great for potting soil!

Chevy Chase, MD(Zone 7a)

Rick -- that is all really helpful -- thanks. I was at Home Depot today, and they had 2 cubic feet bags as follows (Garden Pro Brand):
1) pine bark nuggets for $2.82
2) pine bark mini nuggets (still pretty big) for $2.82
3) pine bark mulch (seemed very fine -- more so that pine bark fines for $2.82
4) shredded hard wood for $2.75

A nearby garden center (American Plant Food) has "soil conditioner" (which is pine bark fines) for about $10 for a 2 cubic foot bag.

I could get the mini nuggets and run it through hardware cloth -- what say you? I need to build a sieve. The "mulch" seemed too fine to mess with, but I could buy a bag just to see.

Chevy Chase, MD(Zone 7a)

Just re-read your note and got to your sentence about Home Depot mulch: "Home Depot bark mulch tends to be filthy logyard waste: dirt, pebbles, sticks, trash and probably weed seeds. Plus it sits in the rain, soaks up water, and ferments anerobically or in hypoxic conditions. Alchol, organic acids, aldehydes and ketones can build up, which are all toxic to roots hiars if there's enough of them." Do you know what brand you are talking about? The stuff I peeked at (bagged, but one bag was ripped) didn't look bad. Maybe you are saying I should just buy the garden center stuff (which costs 4 times as much).

Northeast, PA(Zone 6b)

Will say it again... I've done perfectly fine with many many brands of seed starter. I feel more comfortable with it vs mixing in bark or such since its sterilized.


Chevy Chase, MD(Zone 7a)

Thanks, Tammy. I'm intrigued/convinced by Tapla's advocacy of an airier mix, though I've used seed starter mixes with good results and may well return to them for convenience, if nothing else.

Northeast, PA(Zone 6b)

I keep a bag of chicken grit to give the mix better drainage. I use it as a topping for seeds that need light - just sprinkle them onto the grit. I've mixed in perlite or vermiculite as well or instead too.


Chevy Chase, MD(Zone 7a)

Thanks, Tammy!

Everett, WA(Zone 8a)

>> Do you know what brand you are talking about?

Only that "PNW" was in the brand name. I think most mulchs, asnd many soil mixes or soiless mixes are bolended locally with whatever is cheapest locally.

You might have better luck with HD mulch than I did.

I agree that anything that has mostly "fine stuff" is not worth bothering with.

If it really is mostly nuggets and not shreds, you'll still have to do some screening and maybe some choping or mincing. I think the best thing about shreds is that they might be 1-2 mm in thin dimensions, but a inch or more long! That is great for "openess".

I saw similar prices at HD, but lower quality. One good thing about mulch: if it is not suitable for seedling mixes, it is still good for mulch. And even betteer if you screen it and mix the fines into outdoor soil, and use the big chunks as top-dress-mulch.

A pricey nursery near me had very good-quality pine bark mulch (dry, and mostly shredded not chunky) for $7-8 per 2-cubic-foot-bag. I love that stuff! Medium-coarse was better than fine, since there was much less powder.

What I'm really trying to do is re-create double-screened pine bark at a lower co0st by screening it myself.

Everett, WA(Zone 8a)


>> I've done perfectly fine with many many brands of seed starter.
>> I keep a bag of chicken grit to give the mix better drainage.

Many people agree with you - maybe 70-80% of posters that I've read. B ut I've had terrible luck with the soiless seedling mixes I've bought and consider those "powdered peat".

I agree that grit improves drainage, but I think that bark shreds open the mix up much more than grit does by itself.
And shreds plus grit are even more effective.
And bark mulch is cheaper per cubic foot (and lighter to haul in and out of the trunk).

Until I manage to curb my over-watering, I need a very fast-draining mix.

>> I feel more comfortable with it vs mixing in bark or such since its sterilized.

True, what gardeners call "sterile" is desirable if damping off is a problem. But using too-wet "sterile" commercial mix gave me a lot of damping off, but the dry-surfaced bark mix has never once given me any damping off.

BTW, what gardeners call "sterile" is really just "very clean". If you were to add a small fraction of a gram of "sterile" soiless mix to some Petri dishes and add sterile nutrient broth, I think you would see millions of bacteria.

My theory is that damp conditions are 90% of the cause of damping off, and large or small initial populations no more than 10% of the caujse. Air goes past seedlings, and dust falls from the air - neither is sterile. There are always SOME bacterial and fungal spores unless you own a clean room.

That said, very clean mix is very desirable, and nearly sterile conditions are probably even better than very clean.

But for me (overwatering me), fast drainage is best of all.

Northeast, PA(Zone 6b)

And a fan is always a huge help in preventing fungal (and insect) problems.


Post a Reply to this Thread

You cannot post until you , sign up and subscribe. to post.