Where there is plenty of light but no soil, grow food plants in containers. Plants thrive in pots on rooftops, balconies, decks, paved driveways, and other nontraditional locations. The plants that do well in limited spaces are the same ones that thrive in containers. ‘Salad Bush’ cucumber grows beautifully in a pot. Baby lettuces such as ‘Mini Green’ fit easily in window boxes. The critical factors for successful container gardening are sufficient sun and soil deep enough to sustain moisture and accommodate roots.
Otherwise, containers can be any size and made from just about any material. The shallower the container, however, the more often you need to water and fertilize.
Planters, tubs, and pots suitable for vegetables and some fruits come in all shapes and sizes. Be sure that any container you choose has holes in the bottom for drainage. Without proper drainage, excess water is trapped at the bottom of the container, causing roots to rot because of lack of oxygen.
Wood planters are attractive, and if you are handy with a hammer they are not difficult to construct. Redwood is a lasting and naturally beautiful material for planters. Although it is expensive, tubs and planters made of redwood remain in fine condition for years. Planters of inexpensive wood or plywood often rot in one or two seasons; the combination of damp soil, frequent watering, and everyday weather takes its toll.
Plastic containers work well and are becoming more attractive all the time. They are ideal for balconies and roofs because they are lightweight and durable, and the soil inside does not dry out as quickly as soil in clay pots. Clay containers are porous, which allows for beneficial air exchange, but this also allows them to dry out quickly, and they are easily chipped, broken, and discolored. But so long as they have drainage holes, both clay and plastic planters make fine containers for vegetable and fruit plants.
It is unnecessary to cover drainage holes with gravel or shards of pots. The drainage is not improved and the gravel blocks the holes. A layer of window screen or newspaper over the holes effectively prevents soil from washing out.
Synthetic growing media are ideal for containers because they are lightweight. Heavy planters can cause structural damage to rooftops, balconies, decks, and patios.
Perennials growing in planters are more susceptible to heat, cold, and drought than plants growing in the open garden. Give them protection from extreme weather and watch them carefully for drying out.