What did you plant? For cooler crops, this would be ideal once the seeds have actually emerged.

For warm weather crops, it might be a problem. The critical temperature for seedlings is the soil temp. In your tray, the soil will warm and cool more rapidly than the ground.

Also, the medium in the tray will dry out more rapidly outside in the sun and wind.

You'll have to be careful to keep close watch on them.

Next year, you might consider a grow light inside.

I'm trying to keep it all organic and natural whcih means I can't use a grow light.

You can use a grow light and still be organic. Nothing in the NOP prohibits it. I wonder about the peat pellets - were they certfiied organic? A lot of peat products aren't because of the wetting agents.

Using a grow light doesn't = non organic as far as I know! Maybe for next year you can build a cold frame for starting your seeds.
Good point ajsmama about the peat pots! Nancy

Sneed, there's nothing "natural " about how you're growing the plants. Trying to provide a reasonable facsimile of natural light is essential to indoor culture. Think about it.

I actually like the temperature for seedling development. Bottom heating is extremely helpful for germination, but after that a cooler air temperature is ideal.

I hate those pellets...good luck with them.

No one has really been able to answer the original question - what kinds of plants, how long per day, now that they've germinated (? I assume, they don't need light until they have their first true leaves) they will need long days (14 hours, or as long as you can give them without artificial light). I have never tried leaving seedlings outdoors from day 1 but if there is no other light source you can try it. Most of us start them under lights and then harden them off before transplanting. I'm assuming these aren't cool weather crops because it's getting late for that in LI - I'm farther north in the foothills and I am trying kale and spinach because I started them a month ago but the weather has not cooperated for planting (too hot and dry, now getting cooler and rainy the next few days so they're going in this morning).

Put them in a clear plastic box to protect them from wind and animals, if it's cool (tomatoes and peppers don't like below 50) take them in at night.

Most importantly, take the pellets and drop each one into a 6-pack or a pot and add potting mix, keep watered. I've never used the pellets but like I said peat dries out and is hard to get wet again, the roots will die if they get dried out. Once the plants have their true leaves they will need the light and some starter fertilizer (very weak) found in most potting soils. I liked Espoma Organic Seed Starter but it was a bit heavy, ProMix BX or Fafard (I use #2) are better, have more peat and vermiculite, but they aren't OMRI listed. I suppose you could buy a small bag of perlite (vermiculite is harder to find) at Walmart and some peat too (don't know where to buy in small bags) and mix it with the Espoma if you want to stay organic.

I don't know about your assumptions, ajsmama. I think seedlings need light as soon as they emerge after germination. Waiting til they get true leaves is too late.

Nor is it clear that the OP has only warm-weather crops in the tray. I would think it's much too late to have cool-weather crops germinating now on Long Island, but the OP's priorities are clearly different and not promising.

If indeed there are both cool and warm weather crops, I would divide them into two trays, put the cool stuff out and transplant as soon as hardened, put the warm stuff out in the daytime and be able to bring in if it turns too cold.

I have put seedling pots outside in full sun after they've germinated. I did this with both brussels sprouts and basil this year, and both did fine. The sprouts I left out all night since they are cool-weather crops, but I brought the basil in at night if the temps dropped below 50. (The sprouts are now in the garden; the basil is still being taken in and out. So far, so good.)

As for the lighting requirements, yes, seedlings need light as soon as they germinate -- waiting until they have true leaves is way too long. And, of course, using indoor grow lights has nothing to do with growing organically.

As far as I know, they only *need* light when true leaves emerge since cotyledons don't photosyntesize. Certainly doesn't hurt to get them in light once they emerge, just don't think they need it that soon whereas they definitely need it (ASAP) when the true leaves emerge. I was trying to balance the need for light vs risk of putting them outside too young/while they're still germinating - I use grow lights so get them under light and off heat mats as soon as most have emerged (though I haven't noticed any problems with the earlier ones not being under lights while I was waiting for rest to germinate, I don't start them in total darkness either).

And actually, some seeds need light to germinate, others don't, some need to be chilled first, some need to be nicked a little, others need to be soaked, so yes, I was generalizing based on what I guessed the most likely crops to be.

Since OP hasn't told us what kind of seeds he/she started (or if they've even germinated yet) I was making what I thought was a reasonable assumption but admit I could be wrong.

Put it on concrete outside in 60degrees of all day direct sun and its more like 80 degrees. It's what I do until I can get my plants in the ground. I have grow lights and they do good but I prefer to harden them off early this way. just be sure to do it a little at a time. I do this every year with all of my seeds and haven't had a problem yet. I use my driveway.

ajsmama, I don't want to seem contradictory, but cotyledons do photosynthesize. So do stems, to a limited degree.

I've seen a lot of seedings get leggy from insufficient light before the true leaves emerge.

I never knew that. Most of the time the cotelydons on my tomatoes turn yellow and fall off at some point (if I don't take them off when I pot up). My cousin's in the greenhouse without artificial lights were horribly leggy but they already had true leaves so I don't know when they started getting that way. Interesting, I should get them some lights for next year and have them put them under light right away.

But this still isn't answering the OP's question - though unless he/she comes back and clarifies what type of plant(s) and whether they've germinated yet, nobody can really answer if it's OK to leave them outside for a while right now.

*Right now* may not be a good time for setting things out in LI. Getting cold up here in CT, high 30's early tomorrow and then Tuesday AM predicted to be 34 with "feels like" temp of 31 even with just 5 mph wind (probably windier here) and 70% RH. I'm going to cover my newly-planted kale and spinach just in case. Not even going to hit 60 the next couple of days.

Yes, this late cold snap emphasizes the importance of separating the seedlings. In this weather, I'd leave more hardened brassicas out in the daytime, bring them in at nite. But I left the tomatoes and peppers inside all day, yesterday, even tho I've been hardening them.

Which, of course, is why artificial lighting should be available.

What's valuable about this discussion is how it illustrates that, ideally, all seeds would be sown outside in perfect weather. Starting inside, starting in artificial media and pots, transplanting outside is all unnatural and not ideal for the plant. Transplanting is always stressful. Sown-outside seeds are acclimating from the outset to conditions.

But reality isn't ideal. Our weather isn't ideal. Freezes can kill young and tender seedlings. If we direct-sowed everything, people in northern latitudes would never be able to grow, say, tomatoes. So we do what we can to extend the growing season and try as far as possible to approximate ideal conditions by artificial means.

This post was edited by ltilton on Mon, May 13, 13 at 9:20