Green Scene

Grow any plant, any season, in a greenhouse

By Joel M. Lerner
Saturday, March 6, 2010

The ending of winter and approach of spring intensify cabin fever and turn gardeners' thoughts to the potential that greenhouses -- and their fancier cousins, conservatories -- offer.

A greenhouse or conservatory enables you to grow any plant you want -- winter, spring, summer or fall. Nurture vegetables, flowers, shrubs or trees from seeds or cuttings. Raise exotic flora or overwinter your patio containers planted with bananas, oranges, palms or other tropical plants. Greenhouses will allow you to provide proper climate conditions 365 days a year.

Greenhouses are within the reach of most homeowners, especially if you build one from scratch or buy a kit. They come in a variety of sizes, shapes, colors and materials. There are solariums no larger than bay windows that serve as small greenhouses. You can utilize sunrooms or enclosed swimming pool areas -- any environment that can be controlled will work as a greenhouse.

Gardeners who dream of having a plant conservatory might have to compromise on some of their ideas unless they own a large home with lots of glass and tall ceilings. Conservatories are room-like structures, often custom-designed, that are sometimes extensions of homes and used mainly for exhibiting plants. Beautifully appointed conservatories were a favorite of wealthy Victorians who loved displaying their orchids, tropical palms and other exotics.

Greenhouses, the more utilitarian alternative, can also be custom-designed and -built and are intended to be controlled environments for the propagation and growing of plants.

If you want a traditional greenhouse made of wood and glass, there are companies that specialize in installing and restoring historic greenhouses, which tend to be ornate and expensive.

If your tastes run more economical than elaborate, however, prefabricated units are available. Some of these are designed to attach to a house where a portion of the wall serves as one of the walls for the greenhouse.

The greenhouse part of the structure can have a wood or metal frame. Wood is more expensive and requires additional maintenance; aluminum is cheaper and generally maintenance-free. The "glass" element can be actual glass or a cheaper alternative such as polyethylene, polycarbonate or fiberglass. The panes can be transparent or translucent, depending on the location of the structure and the season.

Glass is preferred, and it should be glazed with a finish to reduce glare and heat gain. Glass also should be tempered. Tempered glass has been heated to 1,200 degrees Fahrenheit and then cooled, which can make it up to four times as strong as regular glass.

Floors require a liberal layer of gravel for drainage and a raised walk made of wood, brick, stone or other fabricated material to provide a dry walking surface. Some greenhouses have concrete or other masonry surfaces for more permanence than wood. Floor drainage should be carefully designed and installed to control irrigation runoff.

The design of floors will depend on how you are planning to water plants. Some greenhouse plants need water only on their roots, while others require moist atmospheres.

There are tubes that will drip water onto planting mediums in whatever way you would like it delivered, spraying or dripping it directly into the soil. Hoses and watering wands offer other choices.

CONTINUED     1           >

© 2010 The Washington Post Company