I have a nice garden which I have made using vermicompost. Plus I have used cow dung manure. I get a lot of flying cockroaches in that. How to get rid of this.
You could try sprinkling food grade diatomaceous earth around the garden area where they frequent, but it requires reapplication once it gets wet. It will desiccate the insect's exoskeleton (it doesn't discriminate the good from the bad). Roaches tend to clean themselves frequently so they should get it on them.
I would mix in a ratio of powdered sugar or cocoa powder (between 1:3 to 1:1) and place bait in containers or LIGHTLY sprinkle areas that they frequent that are dry like near bricks and stones and other hiding places that they go to. Other than that you'd have to go with a commercial product like the baits that use boric acid or another chemical or skip the dung if the roaches continue to be troublesome. If there is a food source then they will find it.