I have a 6x4 greenhouse the last 3 years i put in tomatoes. Down one side variety is shirley on the other side i plant 1 cumber plant. the tomatoes have done really well. but the cucumber has only produced about three cucumbers. the leaves turn a creamy colour the rest of cucumbers just shrivel up and die. both plants grown in same way plus the same compost. Need help to sort out this problem. thanks. very keen gardener.