Question
I read something about cutting back your petunias to 2-3 inches at the begining of july to revitalize them. I have never heard of this before, would you recommend this?

Answer
Petunias grow long "arms" and eventually it becomes skinny, poorly flowering and not very attractive. This happens gradually over the growing season, as the "arms" enlarge. Once flowers wither on the stems ("arms") the stems will continue to grow and new flowers appear. This can result in long stems with flowers at the end, and nothing in the middle (aka a "old bald man" look).

You can cut the petunias back to a few inches (3-5") of the crown and in 3-4 weeks, flowering will reoccur. This will help produce compact plants, with more flowers. I do this every year when the plants go from prolific flowering to a lackluster show. If you are happy with the amount of flowers on the plants right now, then do not cut back.

Also, fertilize petunias on regular basis. Use OSMOCOTE 14-14-14 (Multicote, etc) every 3 months. You can also use the powdered fertilizer which dissolves in water, such as Miracle Grow 15-30-15, Peters 20-20-20, etc every 14 days (1 tbsp per gallon of water). Regular fertilizer will help the petunias flower, too.

If you are going on vacation for a few weeks, you can cut them back then, and they should flower when you get back.