Hello! One of my varieties of tomatoes are struggling and im not sure how to solve it, or what the root cause is?

The tomato itself is a indeterminate sauce tomato. As you can see from the images, I've been getting horrible leaf curl and twisting. The branches are drooping and pale in color, and the tomato itself just looks a bit sickly. Does anyone know what this could be? It is only affecting one variety of my tomatoes (I planted 5 total). All planted on the same day and have got the same treatment.

Some details -
Has not affected vertical growth
4x4 greenhouse kept at 60° f.
Low speed fan on and off every 2 hrs (9am-9pm)
3 LED Blue/Red lights covering 4x4 space, on for 12hrs/day
Started in small 12 cell tray, potted up to 3.25" pot at 4 weeks (issue occurred in cells)
Fertilize with 1/2 strength fish fertilizer 1x week (after true leaves formed)
Bottom water as needed

Some tomato varieties are so susceptible to fungal infections that even the smallest amount of water on the leaves will cause this. I have some varieties that even a single drop of water on the leaf while it's young will ruin the leaf entirely. That may be the case with this one.

I haven't done a scientific study yet, but I've been having leaf curl on tomatoes under LED lights. My anecdotal evidence is that I tried one tomato only using light from the window and it didn't have the problem that the ones under the LED had. It was terribly leggy, but no leaf curl and subsequent problems.

I dunno. Reading the description my first guess was blight, but the pictures don't look like blight.

60 F is a little cool and sometimes cool temps can promote fungal infections. Can you raise the temperature to 75 F or so? And maybe cut off the affected leaves.

Henderman said: I dunno. Reading the description my first guess was blight, but the pictures don't look like blight.

60 F is a little cool and sometimes cool temps can promote fungal infections. Can you raise the temperature to 75 F or so? And maybe cut off the affected leaves.

I suppose I could? I have a heater in there that is connected to a probe that is set to kick on if it drops below 60. That really only happens at night when outside temps drops into the 40s. Typically runs at about 65-70 in the tent. Now that you mention fungal and moisture, I noticed some condensation that has shown up on the window, and I'm wondering if maybe the humidity levels are too high (if thats even a thing)?

Rubi said: I haven't done a scientific study yet, but I've been having leaf curl on tomatoes under LED lights. My anecdotal evidence is that I tried one tomato only using light from the window and it didn't have the problem that the ones under the LED had. It was terribly leggy, but no leaf curl and subsequent problems.

The lights were one of my thoughts as well. I didnt know if it was too intense, but based on my light sensor reading, PPFD and DLI numbers are within the recommendation in the center of the light, and slightly below on the outside edge of the spectrum. I have also experienced curl but always equated it to over zealous watering....maybe there is something to the LEDs?

dave said: Some tomato varieties are so susceptible to fungal infections that even the smallest amount of water on the leaves will cause this. I have some varieties that even a single drop of water on the leaf while it's young will ruin the leaf entirely. That may be the case with this one.

That's interesting. I had something similar happen with a variety of determinate slicing tomato last year, when all the rest were fine. Do you think high humidity will affect the seedlings? I mentioned in another post that Ive noticed condensation building on the window.

I know I can't grow Rosella Purple unless the conditions are perfect.

I don't know what you're growing there but I will definitely say that moisture is the enemy when fungal susceptibility is an issue. Humidity is an enemy of tomato seedlings for sure.