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bower · April 22, 2018

I agree it's absolutely fungal... looks awful.

I don't know anything about aberrant early blight but it could make sense since early blight typically affects the lower leaves first.

Just a few thoughts about tomatoes and their lower leaves. At some point in the season the plant decides that those low leaves are not useful any more - not getting enough light; not close enough to the fruiting action; - and the plant decides to scavenge the nutrients that can be moved from old leaves to other leaves that are getting more sun. If there's no disease and no susceptibility to disease, the lower leaves just yellow and fall off, but more usually, the leaves will develop whatever disease that plant happens to be susceptible to or is available in the environment to infect the dying leaf. It's as if the plant had withdrawn immune support from the leaf while sucking away whatever nutrients can be moved... and this is where disease happens.

So from what you said about improving when you go outdoors, I think part of the problem is that the light is not penetrating to those lower leaves. Secondly I would doubt that overfertilizing is the problem, because a plant with nitrogen to spare doesn't need to scavenge from old leaves. They will keep em green even in the shade if they're not short of any nutrients.

So it seems that there's a combination of environmental and nutritional factors plus some fungal thing that maybe came with the potting mix.. Crowding creates damp areas low in the seedling canopy, and it's enough for a mildew or other fungal disease to set into the leaves that are being sacrificed anyway with not enough light....

JMO.

Hope the weather gets good enough for you guys to plant out soon.

April 22, 2018	#33
bower Tomatovillian™ Join Date: Feb 2012 Location: Newfoundland, Canada Posts: 6,793	I agree it's absolutely fungal... looks awful. I don't know anything about aberrant early blight but it could make sense since early blight typically affects the lower leaves first. Just a few thoughts about tomatoes and their lower leaves. At some point in the season the plant decides that those low leaves are not useful any more - not getting enough light; not close enough to the fruiting action; - and the plant decides to scavenge the nutrients that can be moved from old leaves to other leaves that are getting more sun. If there's no disease and no susceptibility to disease, the lower leaves just yellow and fall off, but more usually, the leaves will develop whatever disease that plant happens to be susceptible to or is available in the environment to infect the dying leaf. It's as if the plant had withdrawn immune support from the leaf while sucking away whatever nutrients can be moved... and this is where disease happens. So from what you said about improving when you go outdoors, I think part of the problem is that the light is not penetrating to those lower leaves. Secondly I would doubt that overfertilizing is the problem, because a plant with nitrogen to spare doesn't need to scavenge from old leaves. They will keep em green even in the shade if they're not short of any nutrients. So it seems that there's a combination of environmental and nutritional factors plus some fungal thing that maybe came with the potting mix.. Crowding creates damp areas low in the seedling canopy, and it's enough for a mildew or other fungal disease to set into the leaves that are being sacrificed anyway with not enough light.... JMO. Hope the weather gets good enough for you guys to plant out soon.