Planter boxes are an attractive and nearly labor-free way of growing flowers on a patio, deck or balcony. The use of planter boxes means that bending, stooping, digging and weeding are at a minimum. However, if your planter boxes are constructed of wood, the bottoms can rot quickly, shortening the life of the boxes. A few precautions can extend the life of your planter boxes, and they will hold your blooming beauties for many years.
Check to be sure the planter box has bottom drainage. Drill two 1/8-inch holes in the bottom of the box, about 3 inches from each end. Add two or three more holes, evenly-spaced between the outer holes, depending on the length of the planter box.
Use a peat-based commercial potting mixture. A mixture of peat moss combined with other ingredients such as vermiculite, perlite or sand will drain well, keep plants from drying out too quickly, and it will be lightweight. However, avoid using peat alone, as it won't hold water and will become compacted. Never use garden soil, as it is too heavy, will compact and won't drain well.
Provide air-circulation under your planter box. Cut two 2-by-4-inch pieces of lumber equal to the front to back measurement of the planter box and nail them to the bottom, or set the planter box on bricks. Anything that provides at least 2 inches of space under the box will work.
Leave air space around your planter boxes. Avoid crowding planter boxes too closely together. Don't place the boxes too near a wall, fence or other plants.