Plants--like humans--need nitrogen, phosphorus and potassium for health. Adding oak or fruit tree leaves to a compost pile adds potassium. Banana peels are another good source of potassium for composting. Adding banana peels directly to compost adds the needed potassium to the pile. If you do not have room for a compost pile in your yard, you can still compost banana peels, using the trench method around individual flowers and plants.
Chop up the banana peels. A whole peel can be added, but the size material in the compost pile affects how long it takes for the compost to decompose. According to the University of Virginia Extension, “shredded materials break down faster than whole materials.”
Add the banana peel to the compost pile; this is the wet--or "green"--material. Add a handful of leaves, a sheet of newsprint or ripped up cardboard on top; these are the dry--or "brown"--materials.
Sprinkle water on the compost pile if there has been no rain. Turn it every two or three days. The compost pile should have the consistency of a squeezed-out sponge.
Move the mulch around the flower to one side, in order to expose the soil. Dig a trench that is about 2 to 3 inches deep near the base of the flower. Dig gently to avoid harming the roots of the plant.
Tear the banana peel into strips. Place several of these strips in the trench.
Cover the banana peel with soil and tamp down with your hand. Spread the mulch back over the trench.