Dry set on Tomatoes

 

Only just twigged what it was, match head sized fruits doing nothing, about a 50/50 set rate on the first trusses. Dr Hessayon recommends spraying with water once a day to stop this. Is that the best way and do i need to do it when it's cool, like today?   

when its hot weather you need to syringe the toms spray over the top this helps to set toms and will stop your problem happy growing

My tomatoes have lots of dead flowers but few set fruits. I have just started misting the flowers.
I had to have my greenhouse door open all day and night for the last few weeks as I had mildew on the leaves. At least that seems to be under control now, but I think it left the air in there dryer than usual during the hot weather.