Plants in bags in a greenhouse can be at different stages, either because you're seeking continuity, because you didn't have all ready at the same time or because cherries & beefs set fruit at different rates.
Correctly, one should start feeding at first fruit set. So, you have a watering problem. Do you religiously stick by the rules, or do you say 'hard luck - you're getting feed whether you've got fruit or not?'
If the latter, how detrimental can that be?
Not a lot you can do to avoid it Tim. Shouldn't be much of a problem so long as they are not weeks apart. Mine in the greenhouse are direct in the soil so i'm feeding melons and cuc's with Tom feed.
Weeks? We've been picking some since 2 /6, whereas others are only just flowering!