Container gardens accent and define outdoor spaces. They establish focal points, define style, create privacy or mask flaws. The choice of a plant container can affect the appearance of an entire landscape area. Many alternatives are available in addition to the traditional flower pot or box planter, some handmade, some re-used or recycled. Your task is to choose containers in which plants can succeed and that fit into your overall landscape design.
To function successfully as self-contained garden spaces, each plant container must have certain characteristics that are either part of its composition or added to it. The container must be large enough to accommodate the plant's root structure and allow for growth. It must drain sufficiently to avoid root rot. It must be porous enough to allow air circulation in soil but impermeable enough to keep water and soil from washing through. It should be substantial enough to insulate the roots inside against hot sun and sudden frosts. And it should be stable enough to stand against everyday breezes, the occasional squirrel and summer storms.
Once these structural basics are met, the container must meet certain cultural requirements. Plants like spider-plants (Chlorophytum comosum) or asparagus fern (Sprengeri fern) tend to become pot-bound quickly. They may require larger, thicker containers to contain their strong, pot-breaking roots. Most plants prefer a slightly acidic base but the use of reactive container materials like limestone or metals can alter pH and buffers such as liners should be used. Starting with the right balance is always easier than having to correct it in a container.
In addition to the standard flower pots and rectangular wood boxes, a variety of objects can be adapted for use as container planters--as long as they have enough living space for their occupants. Galvanized tubs, halved wooden barrels and steel tanks can all be adapted for use as container gardens. Hollowed stumps, wagons and baskets make good rustic containers. Even decorated plastic bags are used to create hanging containers for everything from sweet pea vines to tomato plants.
Recycled milk crates, garden carts and toy boxes can all be given a new coat of paint for informal gardens. Copper wash basins are stylish, but expensive, planters. Containers can be elevated or set upon wooden crates, cement blocks or even old ladders.
Common materials for planters are terracotta, stone and wood. High-end containers may be ceramic or stoneware. Inexpensive resin can be molded to resemble expensive pottery. Baskets and boxes can be woven out of wire and lined with peat pots or sphagnum moss. Do-it-yourself materials include "Hypertufa", an artificial stone made with peat, perlite and cement. Many surfaces can be painted or faux-finished to resemble other materials or antique pieces. Permeable objects like wire baskets, leather and paper-mache must be lined; drainage holes should be added to solid materials like metal and wood, where standing water can rot the container.