Why are my tomato plants dying? I live by the sea and the leaves are all diseased, can you help?

Can you give some more details of the 'disease' (i.e. describe the actual appearance of the leaves)? Are the leaves just going yellow or are they affected by blight (concentric rings which go brown, black patches on stems etc.)? Are they being grown in pots or the soil, in the open or in a greenhouse? Have you used fresh compost?

leaves are yellow,tomatos brown patches,black patches on stems. Tomatos are grown in pots in the open and have fresh compost.

a dry wind and a lack of calcium may make brawn spots on tomatoes, also some fungus,and pollution may be as well. an anti fungus treat and may by put them in a green house to avoid salty winds and bad rain.may be an iron and algae food on leaves,every two weeks,not to much,to let them breath.

brown spots on tomatoes may be a lack of calcium and dry wind as well
put them in the green house,to avoid salty winds an polluted,salty rain.tray an anti fungus. also some food with algae and iron on the plant and fruits,not too much,to let them breath

Black patches on the stems sounds horribly like blight to me, even though windy and by the sea suggests that the spores are less likely to settle.