I have a plastic greenhouse containing cucumbers, courgettes and three types of tomoatoes; plum, golden and russian black. Everything was going well until last week when some of the leaves on my tomoato plants have started to go get black spots on them. The spot spreads and then the leaves die off. This is now affecting some of the side shoots and is working it's way up the plant. It seems to have spread and my cucmber leaves are starting to die off. I regularly feed the plants as the tomatoes now have small fruit on them. I water them once per day in the evening but it is very humid in there at the moment. The plants are in grow bags and I live in the North East of Scotland. I am not sure if that has anything to do with it! Any comments would be greatly appreciated as I will be a bit gutted if I lose everything!