Agree with above, blight is more common on outdoor tomatoes than indoor in the UK, the spores are in garden soil.
I thought blight was an airborne disease, seems there is conflicting evidence.
quote Symptoms appears at the edge of tomato leaves, with dark, damaged plant tissue that spreads through the leaves toward the stem. ... Late blight does not overwinter in the soil because it requires live tissue to survive, but wind can carry spores up to 30 miles away from infected plants.
Quote
Blight spores can survive in the soil for three or four years. Only plant tomatoes in the same bed every three to four years, and remove and burn tomato refuse in the fall.
My dad grew beautiful tomatoes in the same greenhouse for 25 years and I have done so ever since. Never had blight.
I also have an old garden book where the writer says you can compost the blighted plants as it’s airborne and doesn’t live in the soil. Who is to be believed.
I think any new spores would definitely be airborne. Though the spores can be in soil, it is the same thing as potato blight as far as I know. It is well known with potatoes that the best thing is not to grow again for several years in the same spot after blight, because the spores drop to the soil and even infect the tubers.
The 'mechanism' I read about is outdoors when it rains soil is splashed onto the lower leaves, blight sets in, then the new spores (which are then airborne) spread to the fresh growth and upper leaves, which are then more obviously 'symptomatic' of blight.
I grow outdoors, I take care to remove lower leaves and it seems to be all I need to do to ward off the blight, so I've never questioned the concept that the source of the first spores can be garden soil.
There seems to be plenty of sources state that outdoor tomatoes are more prone to blight in the UK than in the greenhouse, so again logical that the difference is exposure to garden soil, as I guess most people grow indoors in a bought in medium.
Though also just as logical that greenhouse plants 'could' be infected by an outside source that is actively creating new airborne spores nearby.
So I've just been out to the greenhouse to put it to bed for the night, and I'm inclined to think there is something amiss, even if not blight. I took some pics... The big tomato plants are sweet olive and choc cherry, and the little ones are golden sunrise. The sweet olive are the ones with droopy leaves, and hopefully you can see they both have some crinkly brown leaves at the end of one or two stems. I now spot the end of one or two leaves on the golden sunrise also are going brown, though not yet crispy, and the vine has yellowing leaves, some of which are brown and starting to drop. The photo of the vine isn't fully showing the extent of the yellow leaves, but there are quite a few at the back of the plant.
There's shading netting on the greenhouse for the first time this year, but the vine has been in there with no netting for four years without this problem, and I don't recall having this before with any tomatoes. All the plants have been getting enough water, and the only odd thing I wonder about is whether they are getting too much iron from the inside of a metal watering can that's going rusty. I'm not yet massively concerned, but I am slightly flummoxed and hoping not to find them all collapsed in a heap in the next few days!
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Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
The 'mechanism' I read about is outdoors when it rains soil is splashed onto the lower leaves, blight sets in, then the new spores (which are then airborne) spread to the fresh growth and upper leaves, which are then more obviously 'symptomatic' of blight.
I grow outdoors, I take care to remove lower leaves and it seems to be all I need to do to ward off the blight, so I've never questioned the concept that the source of the first spores can be garden soil.
There seems to be plenty of sources state that outdoor tomatoes are more prone to blight in the UK than in the greenhouse, so again logical that the difference is exposure to garden soil, as I guess most people grow indoors in a bought in medium.
Though also just as logical that greenhouse plants 'could' be infected by an outside source that is actively creating new airborne spores nearby.
The big tomato plants are sweet olive and choc cherry, and the little ones are golden sunrise. The sweet olive are the ones with droopy leaves, and hopefully you can see they both have some crinkly brown leaves at the end of one or two stems.
I now spot the end of one or two leaves on the golden sunrise also are going brown, though not yet crispy, and the vine has yellowing leaves, some of which are brown and starting to drop. The photo of the vine isn't fully showing the extent of the yellow leaves, but there are quite a few at the back of the plant.
There's shading netting on the greenhouse for the first time this year, but the vine has been in there with no netting for four years without this problem, and I don't recall having this before with any tomatoes.
All the plants have been getting enough water, and the only odd thing I wonder about is whether they are getting too much iron from the inside of a metal watering can that's going rusty.
I'm not yet massively concerned, but I am slightly flummoxed and hoping not to find them all collapsed in a heap in the next few days!