With a greater proportion of people living in town homes, condominiums and apartments, the trend seems obvious. Growing things outdoors in containers is "the wave of the future."

If the horticulture industry wants to keep up, they must cater to the potential buying publicthat people without traditional garden space represent.

Seed developers are striving for plants that take up less space than the traditional offerings. There is more study of the dynamics ofroot growth in contained soil. The sophistication of the growing containers themselves has grown.

Lately, container gardening has comeinto its own, as opposed to its previous status as a substitute for the real thing. There are some distinct pluses.

One advantage thatcontainer gardens have over the earth-bound type is their portability. They can be moved to allow an early spring start indoors and latertaken back outdoors. Or, if sunny spots are limited, a container maybe moved once or twice a day to "catch the rays." Placed above the ground level, containers are also easy to reach, sparing the back and knees.

Containers can be mounted on walls, hang in the breeze, separate areas on a patio or deck, sit on the roof, green up a balcony or fill the outside sill of the kitchen window. Almost anything can beadapted for use as a container.

Clay pots, however, with their porous surface that pulls moisture out of the contained soil, are not recommended for outdoor use. They dry out too quickly. Preservative-treated wooden containers for growing vegetables are also not recommended.

Old wheelbarrows, baskets, plastic trash cans, as well as the more sophisticated plastic containers that garden centers offer, will all work. A container depth of 8 to 10 inches is enough for most plants.

Essential are several good-sized holes drilled in the bottom,or in the sides near the bottom, so that excess water can drain out.If drainage holes are impossible, use a layer of coarse gravel in the bottom covered with a synthetic mesh to keep the soil and gravel separate.

A pot as small as six inches in diameter can hold a nice crop of chives. A few onions or radishes will make it in a 10-inch pot. A small tomato, such as Tiny Tim, will produce in a 10- to 12-inch container. Devotees of new potatoes claim that a kitchen-sized trash can and one or two seed potatoes will produce many tubers. If you have the space, go for large containers. Your plants will grow larger and more vigorously, and the soil won't dry out so quickly.

After choosing a container you need to fill it with a growing medium. Regular garden soil, even good loam, used by itself, doesn't do well in a container. It compacts and cracks, choking off plant roots and the nutrients they need. It is also very heavy.

Horticulture experts recommend various combinations of commercial potting mix, peat, and perlite or vermiculite with garden soil. Sand, the function of which is to help with drainage, may be used instead of perlite or vermiculite if weight is not a consideration. And very recent experiments have foundthat ground up plastic foam works even better than vermiculite or perlite for creating lasting porosity in outdoor containers. (There hadto be a way to recycle this stuff.)

The goal is to create a growing medium that retains just the right amount of moisture, is lightweight but not so light that the pot blows over in the wind and uses materials that are at hand and affordable.

Most of the rules for standard gardening apply to container growing. Some plants require full sun to do well, others grow without fuss in full shade. Some like it hot, some like the cool of spring and fall. Plants need proper spacingand/or support, if tall or vining.

Succession planting -- changing crops or flowers with the seasons -- works well in containers. Mulching the top of the soil with compost or shredded bark will help retain moisture. And, unfortunately, insects and diseases have a way of homing in on even the most hidden, out of reach plants. Likewise weed seeds.

Watering and fertilizing are two fundamentals that container gardeners will spend more time on than yard gardeners. Soil in containers dries out much more quickly than that of a regular garden. Daily checking for moisture may go to twice-daily checking in hot weather. A morning drink that goes all the way to the bottom of the pot andstarts to run out the drainage holes is ideal, but beware of over-watering.

Because watering is so frequent, soil nutrients are leached out of the pots on a regular basis. Additions of a water soluble, balanced fertilizer, per label instructions, are recommended.

Slow-release fertilizers work even better. Like timed-release cold capsules that release medication over many hours, pelleted fertilizers, likeOsmocote, can take several months to dissolve in the soil. They costmore than regular fertilizers, but are applied less frequently.

Some candidates for planting include tomatoes (Basket King, Pixie, Tiny Tim) and peppers (Gypsy, many varieties), carrots (shorter types) and radishes, lettuce (leaf, or butterhead types come in many texturesand colors), "bush" versions of summer and winter squash and cucumbers. Don't rule out vining crops and flowers, like pole beans and peasand morning glories that will gracefully climb deck lattice work or a nearby trellis.

A mix of different annual flowers, or flowers with vegetables and herbs, works just as well in a container as it doesin a regular garden. Keep in mind that cool weather plants just won't perform well in summer, but will out-do heat lovers well into fall.And leave space for each plant to achieve its mature size without cramping. An artistic eye combined with plant know-how can create beautiful pot-scapes as well as landscapes.

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