Hello All - I'd really appreciate some help identifying a problem with my tomato seedlings. They were doing fantastic until maybe 7-10 days ago. Although some are worse than others, it seemed to happen very quickly, more/less all at once, which makes me think it's not a disease, but I could certainly be wrong. I have several varieties, and nearly all of them are affected - interestingly, only the Purple Calabash seem to be fine, and those were super old seeds.
I've attached several good pictures that, hopefully, will make it easy for someone experienced w/ seed starting. If not, here is some background/context that might help:
I started these in 3/4" soil blocks & moved up to 2" blocks. I just put them in the pots seen in the pics on Sunday, and the issue was already going on before that. I did a light spray of Neptune's Harvest (fish & kelp) diluted per instructions on Sunday; no significant response that I can tell so far.
These are indoors on a heating mat under lights. Some of the things I've thought of: 1) Am I over-watering and this is edema? I've started waiting until I see them just start to droop before watering, but it's hard to know if that's doing nothing or if I'm preventing further trouble. 2) I had pepper seeds germinating on the same mat, so I had the thermostat set to 85F - will tomatoes suffer at that soil temp? I've since turned it down to 75F.
Thanks so much for any help. I have a feeling they'll outgrow whatever this is if I can keep them alive until it's time to plant, but that will be at least 2 weeks away - maybe more w/ the crazy weather here in Cinci right now!