why do my greenhouse tomatoes grow very well every year then when nicely established and producing lots of fruit they develop mould on the leaves? this has happened for the last four years.....EVERY YEAR !
You did not describe the mould you get on your plants. There are a few different moulds tomato plants can get, a grey mould (Botrytis) and tomato leaf mould which causes brown purplish patches on the under sides of the leaves and yellow patches on the top, both of these can be caused by damp conditions and not enough ventilation especially at night. You can also get a black sticky mould caused by pests such as white fly.
Thanks for reply, I think its the second one you described. When I start to pick the fruit there is 'clouds' of dust everywhere! Last year the leaves were 'curling' inwards too! I wash pots , clean out the greenhouse and use fresh soil every season. I've used plants I've grown from seed and also young plants bought from garden centre. I am a bit of a novice gardener so its difficult!
It sounds like you're doing the right things. Grey mould loves cool, damp conditions. Ventilation is really important. On warm days, try to open all the vents in your greenhouse and the doors to get as much fresh air in as possible. Spacing is also crucial. It's always tempting to pack in as many plants as possible, but closely spaced plants have humid pockets of air in between them - which fungi love. After the danger of frost has passed you can take some of your plants out of the greenhouse altogether for the summer.
I hope you have a good crop this summer,
Many thanks! I will keep trying....fingers crossed.