How deep to make a planter box for vegetables | Easy Guide

A good depth for a planter box is 12-18 inches. This is deep enough for vegetable roots to go down without hitting the bottom. In a planter box that is 12 inches you can grow vegetables including shallots, snow peas, beetroot, and lettuce. In an 18-inch planter box you could plant deeper rooting vegetables such as tomatoes, peppers, and carrots.