[Ivor Backache]

I am growing three types of tomato all on three separate window sills facing south.
Alicante and Harbinger are showing flowers, but I have a problem with Tamara which is a potato leaf type.
The plants are growing fine with first flowers showing. The trouble is the lower leaves, They are turning white at the tips and slowly the whole leaf changes and dries up. I have cut of the affected leaves and given the plants a general feed. I cannot find anything similar in the books/internet or this forum. Does anyone have any suggestions please.

[8doubles]

Are the affected leaves all on the window-ward side of the plant, I have the same thing and have put it down to sun-scorching as the ones in the window above behind obscure glass show no signs of it.

[Ivor Backache]

Yes they are. These three sets are all in separate rooms and facing south. They are all in the same growing medium--50% compost and soil. The other two sets are unaffected. There is no sign of sickness/virus etc. There is also a net curtain between the plants and glass.
I take your point. Its all happened in the last 7-10 days and we have had some hot weather. But then the central heating has been off. I don't quite understand this problem. I grow tomatoes every year and not has this before.

[8doubles]

Maybe its the leaves near the window have been getting just a little to cold at night ?The upstairs room i spoke of stays warmer than the downstairs kitchen where the white leaves are. The plants are growing well so i hope the loss of the odd leaf will not be a problem.
I tend to remove a lot of leaves when the plant is full grown in the greenhouse anyway.

Ps Cooked during the day , chilled at night should cover it 

[Jay Dubya]

Hi, reading through the topics this subject comes up so many times, i think people do not realise how hot it can become on a window cill on sunny days. In a greenhouse you can ventilate you can't on a window cill, and scorching is inevitable.