Depending on what is in your pots you may, or may not need to feed... Watering should be done on a regular basis, feeding is as needed - what is in the pots?

I would always only feed on moist compost better if you never let compost dry out completely as long as the compost is moist you shouldn't have a problem.

As above, as long as the pots are not too dry, you'll be fine. If the plants are wilting and the soil is arid, i'd not feed until they have had a water incase you scorch the roots

Why not use a feed that you dissolve in water first? One operation instead of two. Most plants don't need feeding after July.