From the looks of it, you should be fine. I get some of that almost every year, and the seedlings have no problems. Letting them dry out a bit might help; I've also read where some folks use a chamomile tea mix (?) to get rid of it.

Hope someone else comes along with suggestions, but I wouldn't stress it.

PV

I wouldn't worry about it. Once it warms up and there is more fresh air circulating and sunshine on them it will be ok.

I can't say for sure but I suspect its some kind of mold.. that happens in dark, damp, warm places--which is what you create in your containers to get your seeds started.

Some of my containers have it, some don't.

I think anything other than the above might harm your seeds/seedlings.

Not a disease, its algae and I don't think will hurt your seedlings itself, although its an indication of too moist sowing medium, little air movement. A little air circulation if your temps will allow will take care of it....

If you've got a whole layer of it on pots you don't plan to plant out for a while, when your germination is finished and you can accomplish it without disturbing your seedlings, just 'fluff' up the surface between seedlings a little, use something like a toothpick, chopstick...

Never hurt my seedlings, interfered with any germination for me in 8 years of WS.

Just give them some extra venting while your temps are warm and just remember to close the containers at night, as the nights still can get very cold.

You should be fine and dandy to plant them out before you know it.

Fran

Thanks so much everyone! Will try to get them as much air circulation as the temps will allow (and will never ever buy that moisture retention stuff again!)

Green's okay, open the containers and place in full sun for a few hours to allow the sunshine to dry the soil a bit, also the sunrays can help control the algae. You can scrape it off if you like. Sometimes I've seen red slime on top of the soil, but that's usually when I've not provided enough drainage or vents and that it's been very rainy and cold, and dark and dreary. Red slime, whatever it is, generally is a fatal marker. It's a rare occurrence because it's caused by my own negligence--not enough sun and not enough drainage and/or fresh air. From my own experience I know that when I see the red slime I can toss the flat contents onto the compost heap.

That algae growth is the reason I stopped using peat pots in my basement. Happened everytime I did. Has never once happened since I switched to reusing plastic yougurt cups.
Haven't got it in any of the ws containers. But when I did have it, I found that scraping it off was fairly easy. In situation where I had too many seedlings to do that I just did my best to loosen the soil. Plants made it through just fine.

I was given the advice of using cornmeal in my mixture to prevent this from happening. I was a newbie last year, so far I don't have any green, but the green did not hurt my germination either. I just squeezed the container to open up some small cracks into the soil and 'voila' circulation.

Any pots that I know will be with me for any length of time before sprouting, I top with chick grit. That discourages the algae and moss too...

I dont have any chick grit on hand, but I do have cornmeal. This may sound a bit slow, but do you pour it on top or mix it in? Did you use fine or coarse ground?

I've got the green stuff this year too, and a few fungus gnats, so I will try the corn meal with some added diatomaceous earth (DE), that should end them both! Good thread thank you for the advice!

Ah, just realized the OP was from March, 2012, not this February, lol...

marcvegan, please research the cornmeal before you add it to your pots, it is a natural germination inhibitor. Inhibiting germination isn't in your best interest.

I keep a supply of granular BTi on hand for fungus gnats, it's the only thing I've found that really works without adding something toxic to pots. BTi - Bacillus thuringiensis subspecies israelenis. The subspecies is important, this particular BT is only effective for mosquito and gnat larvae. Our winter has been so mild, I treated pots outside just a week ago, a few with sprouted seeds and others with cuttings that are rooting.

DE is for sure nontoxic, and my plants are already up so there is no germination issue, besides, I picked up the cornmeal today and over 200 plants now have the DE / Cornmeal mix on the top of their soil. Really, I think it should be ok, my giant red celery are 2 ft tall, heirlooms tomatoes are a good 8-10 inches, 2 ft papaya trees, Goji and Golden berries, they've all got the mix, no germinating left to do, although I will take it off of the little tray of purple curly kale I just planted. . I know cornmeal is good to keep weeds from germinating in your yard perhaps it will help with the green algae, the DE should do ok with the fungus gnats. Heck my next problem to conquer is planting too early, not good to have 2 ft celery under shop lights waiting for spring in Kansas City!!! eek!