There are two reasons to raise or
elevate garden plants; to provide good drainage, and to increase the soil
temperature. Some plants prefer both of these conditions for maximum growth
and Hilling Plants
When soil is elevated, it increases
the surface area exposed to the surrounding air, and at the same
time loses some contact with the cool Earth. Plus the cooling moisture
tends to drain away from the elevated root zone. All this has the effect
of increasing the soil temperature in the area of the root system. Just
a couple degrees may be beneficial to some heat-loving plants.
Most plants that love heat also
detest wet roots. Being elevated allows the water to drain down into the
lower surrounding soil. But this also means that you may have to water
elevated plants more often than if they were not elevated.
Elevation may be done to individual
plants, or rows of plants or a whole bed of similar or different plants.
The idea is to provide the two conditions that elevation allows. However,
the larger the elevated area, the less will be the desired effect. Having
one plant elevated will expose all sides to warming air. Having a row elevated
will expose two sides to warming air. Raised Beds expose only the outside
plants to warming air, and then only if a retaining "wall" is not used.
You can "Hill" individual plants
or several plants with a shovel or hoe. Hilled Rows can also be made with
a Hilling tool that you push through your garden, or by a Hilling attachment
on a Garden Tractor.
Garden Soil may be scraped into
"Beds" or brought from a different location. This is a job that may require
earth-moving equipment from a Wheelbarrow to a Front-End Loader. The Topsoil
may also be taken from paths where it will not be needed to grow plants.
Imported soil may need to be Amended to improve
its texture and nutrient composition.
Raised Beds may be retained by
garden timbers or border retainers like bricks or stones. But these retainers
cut down on the warming effect by shading the soil. Beds are normally raised
by 8 to 12 inches above the surrounding soil. Beds should not be wider
than twice the length of your outstretched arm, so you can reach in to
cultivate, weed, and harvest produce. Raised Beds can be as long as you