Seedling Issue

[heyni1]

Hello,

I started a few flats from seed about three weeks ago. Everything germinated great so I removed the domes and put them right under the lights. Set up seen below.

The two flats on the bottom never developed their first set of true leaves. The cotyledons turned brown and sick looking. I suspected maybe the bottom trays were either not getting enough light (new weird pink grow lights which may stink) or it was colder on the bottom.

I moved the two problems flats up and covered them in the domes again. They seem to have bounced back after a few days covered and now have healthy looking true leaves. The cotyledons are dead looking. See plants below.

My questions are should I trash the whole flats since they may be diseased and would lack of light temperature cause those symptoms?

Thanks.
nick

[kath]

As soon as the first seeds germinate, I remove the domes and get the fluorescent tube lights within 2" of the seedlings. (I'm not familiar with the pink ones.) Make sure there's some air flow, spritz the cells where germination hasn't taken place yet to keep the soilless mix damp but not soggy. What mix are you using? What's the temperature? How many hours are the lights on? Not sure what's causing the yellow cots so soon.

[Nan_PA_6b]

I don't think they're diseased, because 1.) the new growth is fine, and 2.) the problem stopped when you moved them.

I think you're right about the cold and/or light. Looking at that pink light, I would never use that. I would suspect that light is the problem. Was that actually sold as a grow light?

You don't have to trash them, as I don't think they're sick or contagious. They have been stressed but seem to be catching up well.

Nan

[heyni1]

Thanks for the replies. I used burpee organic seed starting mix and it usually 65-68 degrees where the plants are.

Indeed they do market that light as a grow light. They are brand new and after this I am suspicious. I thought I was upgrading! Here is the model:
https://www.amazon.com/dp/B01F53LP46...a-393108070793

You made me feel better that they are not a total loss. I will monitor them closely and report back.

[Nan_PA_6b]

I agree with Kath about taking off the dome.

Nan

[heyni1]

Oh yeah, the lights are on 16 hrs or so a day.
nick

[Al@NC]

Nick,
Does the manual that came with your lights say to keep the lights 10" to 24" from your plants? Mine does. I'm thinking you might have cooked them a little bit, but what's weird is it looks like the real leaves aren't cooked just the initial ones, and your distance looks good in the pic.



Al

[heyni1]

That could be it. Thanks, Al. I never even looked at the manual but did my usual get the light close to the plants! I will check it out.
Nick

[kath]

Hope it's the issue w/the pink lights. Like Nan said, the seedlings look fine aside from the cotyledons and the soilless mix, temp and light timing shouldn't cause problems. Are the stems bent from growing against the dome?

[Al@NC]

You mentioned it could be colder temps but I've only seen that give me purple stems (which you've got). Could be overwatering also?

Al

[Nan_PA_6b]

He moved them and they recovered, not sure how that would be overwatering.

Nan

[heyni1]

I checked them when I got home...still looking better. I moved the pink lights up to 16" or so. I think I may have fried them with putting these LED lights to close. I just automatically did the "get the lights close" thing. Hopefully they keep recovering. Thanks everyone.

20180314_205820.jpg

[Al@NC]

Originally Posted by Nan_PA_6b

He moved them and they recovered, not sure how that would be overwatering.

Nan

Just looking at the pictures of the damages without considering what he said.

Al

[oakley]

Originally Posted by heyni1

I checked them when I got home...still looking better. I moved the pink lights up to 16" or so. I think I may have fried them with putting these LED lights to close. I just automatically did the "get the lights close" thing. Hopefully they keep recovering. Thanks everyone.

Attachment 79708

I have some minor burn/scorching on a few plants from LED. And something
that even looks like sunburn on another plant under a spectrum LED.

[Al@NC]

So when you do a LED light search on google you get alot of pot links but I started seeing several sights say that putting LED lights closer than 10" - 12" inches (or your recommended distance in manual) will give your plants "bleaching". To me these pictures do look a little "bleached" if I had to guess.