Yellow blotches on tomato leaves

[FlowerPowerGirl]

Hi there. I'm new here so here goes...

I have a dozen or so tomato plants in a mini-greenhouse at the side of the house. A couple of leaves on two or three of the plants have a yellow-ish, almost rectangular patch. No dark halos seen. It might be that these leaves have been in constant contact with the plastic covering of the greenhouse. Anyone seen anything similar?

Many thanks.

http://plot35.blogspot.com/

[Chantal]

Hi there FlowerPowerGirl

Welcome to the forum. Sorry, I have no idea what's wrong with your tomatoes, but someone on here is sure to give you an answer soon, aren't you team

[FlowerPowerGirl]

Thank you so much, Chantal. Any advice would be welcome.

I am not normally such a worrier but I am planning on giving away some of my plants and I don't want to pass anything nasty on. I have started to harden the plants off during the day so maybe that will sort them out one way or the other.

[Chantal]

Still no idea what this is, I am hoping it's where the plants have touched the plastic as you suggest. However, does anything on this link look familiar?

http://www.extension.iastate.edu/Public ... PM1266.pdf

[Richard at GS]

Sorry I am a little late on this one. It looks like it could be thrips damage (but could just as easily be scorch from the sun). If you look on the underside of the leaves the bare patches are likely to have tiny black dots (thrip poo) on them. Thrips tend to cause unsightly damage but don't cause a serious threat except in cases of severe infestation.

[Gracie]

Hi flowerpower, I think it could be a virus that is affecting your tomatoes. I hope not because there's not much that can be done. however the other diagnosis is magnesium deficiency, which is very easily cured - just mix 1/2 oz of epssom salts with 1 pint of water and spray onto the leaves, if it is magnesium deficiency it should be put right after a week or so.
Best wishes with your toms,
gracie.

[FlowerPowerGirl]

Sorry for taking so long to respond. I think that it might have been powdery mildew probably due to the humid conditions in the mini-greenhouse they grew up in. Lesson learned - next time I should put the tomatoes outside during warm weather.

Thanks for the advice everyone. I am pleased I found this forum. Bring on Summer!

[Johnboy]

I think one of the mistakes made by those new to gardening is that they read all the expert advice about feeding Tomatoes and do not pay sufficient attention to nutrition in their formative stage.
Over the years, on this forum we have had this problem time and time again.
The expert advice is to begin feeding when the first truss has set but this doesn't mean that they should not have any nutrition prior to this stage.
What should be said by the experts is dedicated feeding should commence when the first truss has set. I feel that if this is followed half the problems with tomatoes would disappear over night. What is actually the trouble is that the tomatoes have be starved until the first truss stage.
JB.