Q.Planter box drainage
What is the best thing to put in the box for good drainage ? Someone said styrofoam peanuts . I have holes drilled in the bottom. Is there any specific soil besides potting soil to use?
To help prevent clogged holes, you can place a piece of window screen or mesh over the holes. Add a layer of gravel, broken terra cotta pot pieces, or even wadded up newspaper to the bottom before adding soil. Yes, you can use packing peanuts. This will assist with draining. Then, add some sand or vermiculite to your soil to loosen the soil and help it to drain better.
Here are a couple of articles that you might find helpful: