Container gardening can transform your outdoor spaces | Home & Garden

Lastly, the right container, in size and form, can project a sculptural quality that gives a space an aura of elegance.

Pots and planters are available in many materials and shapes, but a couple of principles apply to all of them. First, the larger the container, the less the stress on the plants, because soil moisture and temperatures will be more even. Second, the container must drain, unless you’re growing pond plants. And resist the urge to place a saucer beneath a pot; doing so will lead to wet soil and root rot.

Larger pots are harder to handle and are more expensive than smaller ones, but a single large pot or a grouping of three, say, will have a presence that a clutter of small pots lacks.

If you’re putting more than one plant in a pot, use a container at least 19 inches across, said Margaret Atwell, who creates the terrace containers at the U.S. Botanic Garden.

Mass-produced terra-cotta pots are affordable and handsome enough. Plastic versions retain moisture longer, but you may feel as if the world already has enough plastic. Glazed clay pots can complement a color scheme, if you’re planting with one in mind.

The Victorians liked their cast-iron urns and pots, but beware of metal containers. In hot regions, such as the Mid-Atlantic, a metal container, especially a dark one, can get too toasty in a sunny location and cook the plants. One way to mitigate this is to line the container with bubble plastic. Another would be to place it in a shadier location and plant accordingly.