Hello everyone. I am SO HAPPY to finally be on a forum that I can post at without waiting weeks and having so many hoops to jump through!!!

I have a grow tent in my laundry room with two LED grow lights.

I started several tomato seedlings and then all started great and have been growing. It appears that once the plants are reaching a certain age, approximately 1 month old, the outer leaves begin to curl up. They just look sad. I am having trouble knowing if I have overwatering or underwatering. Please, can anyone help guide a newbie!?! I'm happy to post more pictures and offer more information on my set up, just help!
Thanks,
Brian

It's difficult to say for certain, but i have a couple questions that could help in determining the cause.

1) What is the temperature near the leaves? It could be that they are getting too hot and burning. I know that some LED fixtures can put off alot of heat.

2) Do you have sufficient air flow? If it's disease related, air flow will help to reduce it's effect.

I closed the side vents over night and just water a short while ago....so the specs are off a bit, but the temp near the leaves is always about 74-76F. The lights are about 12" from the tops of the plants. The leaves seem to turn along the edge of the tent as well, the furthest away from the light.

In just the last day, the youngest plants have starting with the curled leaves.

I will increase airflow and have better circulation.

Are you feeding them and if so what?

Hi Brian and welcome to TJ.
A closeup of the affected leaves would help (under normal light color too).
But from the way it looks in these pics with large spots under the leaf, it could be edema, caused at least in part by the artificial lights. Just to sum up a gnarly issue, the tomato is quite sensitive to a need for full spectrum light, including the UV violet and far red ranges in normal sunlight. It is a moisture issue, (stomata don't open and water isn't transpired, the leaf becomes damaged as cells are swollen by water they can't get rid of), but light plays a big role, with contributions from relative humidity (higher is worse) overwatering (makes it worse) and extremes not handled well (alternating too dry and too wet).
Do they have to wait much longer to get out in the sun?
If I'm correct about the problem, even a move to a window ledge would help - give them some natural light and they will recover, but the damaged leaves are finished. Best to just remove them. You should then try to keep the potting mix just evenly moist and never too saturated.
Will add that closing the tent is not a good idea - your relative humidity inside there will be higher. Ventilation will help.

Thank you for your reply. I was worried that it would be edema, but with my very limited experience, I didn't really know what to do to stop it or reduce the chances of experiencing it.

To help with the humidity, I opened all the vents, turned on the fan for circulation and have the door opened temporarily to let the excess moisture a way to escape.

For light, unfortunately I have a while to wait still for it to be warm enough in Minnesota to be able to put these little guys in the ground. To help with the full spectrum, I also turned on the red lights on the two fixtures. I just has the blue on up until this point.

I can remove one or two plants and put them in a window to see if they will do better. My hopes are that I can grow 1 or 2 plants year around in the tent so I can enjoy fresh homegrown tomatoes in the winter months. Maybe this plant variety (Home Depot - Burpee Cherry Baby Hybrid and Burpee Supersteak Hybrid) are not great for indoor growing. Although, to be honest, being so new at this, I didn't really keep track of what plant is what....so maybe one type is having the problem whereas the other is fine at this point.

Just another point for you - for next season. Growing in peat pots is difficult. They are either too dry or too wet. In an experiment that I did, growing seedlings in both peat pots and plastic pots, the seedlings in plastic out-performed those in peat. Furthermore, when digging up my plants in the fall, I found that the peat pots had NOT disintegrated and were in fact hampering development of the roots.

Linda

Good to know! Thank you. I want to pass most of these plants to my family and friends when they are ready to be outside. I am hoping to keep one or two to grow permanently inside, so I will repot into a larger plastic pot.

For those plants that get passed out, I will let them know to plant directly into the soil.

Thanks for the tip!

Cool! I keep my waxed carton creamer containers, to use for "giveaways" (with holes in the bottom, of course). I also collect suitably-sized plastic flower pots throughout the year. Recipients can be encouraged to save them for you too .

Linda

Leaves curling upward like that under led lights is a symptom of the light being too intense. Some lights come with dimmers, or you can move them farther away. Tomato seedlings don't need very intense light.

Hi brian, welcome from the uk. I concur with the peat pots, I have tried but they are devilishly hard to moderate the watering. I've used plastic drink cups as an alternative. Hope you manage to correct the issues.

Thank you Amateurinawe, glad to finally find a forum that I can post in!

Thank you Cole_Robbie, I will move the lights higher and further away from the tomato plants. Right now they are about 12 inches away. The lettuce in the middle is growing like crazy, we are harvesting about every 2-3 days.

Since my tent is so tall, I'm thinking of building a shelf, so I can have two levels. I'll have the lettuce on the top and leave the heavier tomatoes on the floor.

I'm open to anything that will help!

Hi Brian
Have a look at micro tomatoes, too.

Thanks Growing Coastal! I just bought a couple varieties of micro plants. Those just may be what I'm looking for to grow in my basement! Worth a try for sure any how

Brian, seeing your close up photo I can say with 100% certainty that edema is the problem. So what you've done is the right thing.
Great point about the peat pots, they really are difficult. I even find peaty potting mixes a problem because my temperatures are cool and RH is higher as a result.
At least you know it's not a pest or disease, just a physiological issue. There are worse things!
You're also right, btw, that some varieties suffer these issues more than others. I'm sure you'll find some that you can grow in the tent for winter.

Thank you Bower and everyone!

I'm early enough in the season and certainly able to take a plant crash or semi crash that sets me back a bit. Thank you so much for the tips. I'll keep you posted during the next few days on the adjustments I made and the results of the changes. I'll change over to plastic cups with holes on the bottom to resolve the peat pots issue. With the lights raised up, the temp and RH lowered, better air circulation, and steadier moisture levels, I think it will be a great and needed change!

Thank you all so much for the help! I'm open to all tips and help

Brian

Gardadore wrote: ↑Sat Apr 10, 2021 1:42 pm Are you feeding them and if so what?

So Sorry, I missed this comment earlier. I am feeding them once a week with

Dr. Earth
Home Grown
3-2-2
Tomato, Vegetable, and Herb Fertilizer.

I mix 8 pumps into 1 gallon and water/feed with that.

Sorry, that's not a ton of information, but I'm happy to offer more if you have questions,

Thanks!
Brian

After reading this post yesterday, I noticed that one variety, Brad's Atomic Grape, is doing the same thing here. It did this last year too along with Lucid Gem but that one is not so bad this year. Out of about 12 varieties these were the only two with issues. They grew out alright and had lots of tomatoes but it sure is an iffy start compared to the rest.
I was thinking that they didn't like the heavier potting soil I used last year and this. It contains some coir and seems to stay wet longer, not something I need. Promix potting mix. Peppers and the other tomato varieties are fine!

I use Promix as well but add extra Perlite when using it to start seeds. It makes it lighter. Coir is the base for my Earthboxes and Growbags.

I agree this definitely looks like edema and besides reducing RH and making sure not to overwater you may ultimately need to look at your lighting as well if you want to grow these year-round. Varieties definitely make a difference and I've certainly seen less of this issue with micro tomatoes. Most of my tomatoes under LED always look a little off to me and I blame it on using cheaper T5 type lights that don't have any real UV emitters, etc. But it isn't enough to cause a big problem and I get them outside hardening off under real sun and they are fine.

But my biggest issue with this is with tomato rootstocks for grafting. With their strong root systems and wild tomato heritage they soak up water fast and they can actually die from the edema before they get to grafting size if I'm not careful. I've seen some of the research on this (link below) and it seems that adding UV to the spectrum you are giving the plants may be more important than managing moisture if you are looking to keep plants inside year-round and growing varieties more likely to struggle with edema. So while I'm definitely being extra careful to have a well-drained mix and not overwater, I've considered adding a UV light as a separate fixture above the area I grow the rootstocks on my shelves so that it fills in that part of the spectrum and hopefully reduces or eliminates the issue for me. But that will be an experiment so I can't say whether that will work for me or in your setup either. And as Bower mentioned, even a windowsill may help arrest it for now.

https://vegcropshotline.org/article/ede ... ootstocks/