Does anyone know what's up with these tomato leaves? At first it was only Orange Jazz that had this but now a few others are starting to get the same on some leaves. The plants are under cover in soil. Thanks in advance.

Chemical burn. Yellowing is the leaf dying back. Not usually a fatal thing, but depends on the chemical.

Chemical as in fertiliser? They've been getting some 2-1-4 liquid feed, other than that just water.

Maybe. Something splashed on the leaves.

I wonder if it's leaf scorch from water droplets sitting on the leaves. The only affected leaves are directly under the seal of the auto-opening ceiling vents, there may be a drip coming through when it rains.

rossomendblot wrote: ↑Mon Jul 12, 2021 4:48 pm I wonder if it's leaf scorch from water droplets sitting on the leaves. The only affected leaves are directly under the seal of the auto-opening ceiling vents, there may be a drip coming through when it rains.

If you mean the sun is burning the leaves because they are wet, there would have to be some sort of oil in the droplets for that to happen. Pure water in sun won't burn leaves, but any sort of oil will sit on top of the droplet and create the magnifying glass in the sun effect.

I have the same problem or similar in my greenhouse, and for sure it is not a chemical burn. No chemicals to burn.
I considered sunscorch, which it could be, and tbh you can get condensation on leaves especially growing under cover, which does predispose to burn type injuries. However over many seasons I've concluded it's caused by some kind of mites.
The usual control that I practice is to scout daily and pick off the affected leaves into a container as soon as you see damage, and carefully dispose, then wash your hands because it is easy for them to hitchhike on your hands or clothes. Sometimes I can feel them crawling on my hands after picking the leaves, although I can't see them. There are also some tiny spiders that seem to feed on these, so if I see the small spiders in the greenhouse I try not to knock them down.
IDK what kind of mites these are but I suspect something with wider host range because certain trees are badly affected here this summer and I believe the little critters are small enough to blow in through the screens. Maybe broad mite or cyclamen mite. They don't produce webs. Either way, they thrive in hot weather, so they are at their worst this time of the season.
Most pics of mite damage on google just show a dead plant, not very helpful. Compare for example pics of hemp russet mite damage in the links below, for the typical mite feeding that starts from the edge of the leaf, leaving yellow spots where the goods have been sucked out. The damaged parts afterwards turn brown. I can see in your pics that there is damage starting further up the leaf, which is just barely starting to yellow. So for leaves like this, it's as well to remove the whole leaf.
https://static1.squarespace.com/static/ ... d+kind.pdf
https://420bigbud.com/how-to-get-rid-of-russet-mites/

Cole_Robbie wrote: ↑Mon Jul 12, 2021 5:39 pm

rossomendblot wrote: ↑Mon Jul 12, 2021 4:48 pm I wonder if it's leaf scorch from water droplets sitting on the leaves. The only affected leaves are directly under the seal of the auto-opening ceiling vents, there may be a drip coming through when it rains.

If you mean the sun is burning the leaves because they are wet, there would have to be some sort of oil in the droplets for that to happen. Pure water in sun won't burn leaves, but any sort of oil will sit on top of the droplet and create the magnifying glass in the sun effect.

I've never had problems with our city water on tomato leaves, but I was talking to someone who lived outside the city limits once, and he said their water would corrode spots on the leaves, or something like that, if he sprayed the leaves and they dried in the sun. I don't know what was in their water; I presume it's well water, and possibly egg water (a lot of people in the country around here have egg water; AKA sulfur water, or water that smells like eggs).

Shule wrote: ↑Mon Jul 12, 2021 7:22 pm

Cole_Robbie wrote: ↑Mon Jul 12, 2021 5:39 pm

rossomendblot wrote: ↑Mon Jul 12, 2021 4:48 pm I wonder if it's leaf scorch from water droplets sitting on the leaves. The only affected leaves are directly under the seal of the auto-opening ceiling vents, there may be a drip coming through when it rains.

If you mean the sun is burning the leaves because they are wet, there would have to be some sort of oil in the droplets for that to happen. Pure water in sun won't burn leaves, but any sort of oil will sit on top of the droplet and create the magnifying glass in the sun effect.

I've never had problems with our city water on tomato leaves, but I was talking to someone who lived outside the city limits once, and he said their water would corrode spots on the leaves, or something like that, if he sprayed the leaves and they dried in the sun. I don't know what was in their water; I presume it's well water, and possibly egg water (a lot of people in the country around here have egg water; AKA sulfur water, or water that smells like eggs).

Sulphur can indeed burn leaves in the hot sun.

Wood pigeons like to sit on the apex of the greenhouse and crap all over the windows. Could something in their droppings leach into the rain water leak and cause the scorch? I'll give them a clean when we have a cool day and the vents aren't open anyway.

rossomendblot wrote: ↑Tue Jul 13, 2021 4:11 am Wood pigeons like to sit on the apex of the greenhouse and crap all over the windows. Could something in their droppings leach into the rain water leak and cause the scorch? I'll give them a clean when we have a cool day and the vents aren't open anyway.

Good idea, ie, you guano wanna try that.

Cole_Robbie wrote: ↑Tue Jul 13, 2021 2:23 pm

rossomendblot wrote: ↑Tue Jul 13, 2021 4:11 am Wood pigeons like to sit on the apex of the greenhouse and crap all over the windows. Could something in their droppings leach into the rain water leak and cause the scorch? I'll give them a clean when we have a cool day and the vents aren't open anyway.

Good idea, ie, you guano wanna try that.

Oy!

At my Mom's setup outdoors, the birds like to perch on the rail that tomatoes are tied up to, and they do let fly and foliar feed em to the max! No complaints from her or from the tomato plants, surprisingly. Perhaps this is where the idea of foliar feeding came from?