how often use fertilizer?

I am about to start feeding my plants phosphorous bat guano, how often and how much should I give them?
-Thanks

They are outdoor and 2-6 inches tall with 1o-15 nodes on each

2-6 inches with 10-15 nodes each, sounds like quite the bush.

just a small pinch each and slowly build up the amount you give them. fertilize every week like this. by the time there two feet u should have worked your way up to a tablespoon a week

I was instructed to mix 1/4 cup to every gallon of water, but i dont know if the size of the plant is too small