Most evenings I give my sunflowers a good dousing with a watering can &
sometimes a drenching with a bucket. About an hour after watering the
leaves seem to wilt - but then perk up later.

Of course it might just be that I need to get to them earlier - but I
was wondering if it's anything to do with the watering that's making
them wilt? And also if it might be doing them any harm?

Regards,

Michael