Special Devices for Starting Plants
In determining the type of equipment for starting early plants,
the gardener must consider the temperature and other climatic
conditions in his locality, as well as the nature of the plants to
be started. Hardy plants, such as cabbage, need only simple
inexpensive facilities, but such heat-loving, tender seedlings as
peppers and eggplant must have more elaborate facilities for
the warmer parts of the United States, and in the well-protected
locations elsewhere, a cold frame or a sash-covered pit on the
sunny side of a building usually suffices (fig. 9). In colder
sections, or in exposed areas elsewhere, some form of artificial
heat is essential. Where only a little protection against cold
damage is needed, a cold frame in which a temporary bank of lamps
can be placed may be sufficient. The hotbed, lean-to, or sash
greenhouse heated by manure, pipes, flues, or electricity are all
widely used, the choice depending on conditions. A comparatively
small plant-growing structure will provide enough plants for
several gardens, and joint efforts by a number of gardeners will
usually reduce the labor of producing plants.
The plant-growing structure should always be on well-drained
land free from danger of flooding. A sunny, southern exposure on a
moderate slope, with trees, a hedge, a board fence, or other form
of windbreak on the north and west, makes a desirable site. Plenty
of sunshine is necessary.
Hotbeds and other plant-growing devices require close
attention. They must be ventilated at frequent intervals, and the
plants may require watering more than once daily. Convenience in
handling the work is important. Sudden storms may necessitate
closing the structure within a matter of minutes. Plant growing at
home should not be undertaken by persons obliged to be away for
extended periods, leaving the plant structure unattended.
A tight well-glazed structure is necessary where the climate is
severe; less expensive facilities are satisfactory elsewhere.
Covers for hotbeds and cold frames may be glass sash, fiber
glass, plastic film, muslin, or light canvas.
In the moderate and cooler sections of the country, standard 3-
by 6-foot hotbed sash is most satisfactory. Even this requires
supplementary covering with canvas, blankets, mats, or similar
material during freezing weather.
The amount of covering is determined by the degree of heat
supplied the structure, the severity of the weather, and the kind
of plants and their stage of development. Farther South, where
less protection is necessary, a muslin cover may be all that is
needed and for only a part of the time.
Many substitutes for glass as coverings for hotbeds and cold
frames are on the market. The most widely used substitutes are
various kinds of clear plastic film. Some of these have a lifespan
of only one season, and others a lifespan of 3 to 5 years.
Clear plastic film transmits as much light as glass in the
visible range, and more than glass in the ultraviolet and infrared
The film comes as flat sheets (on rolls) and in tubular form.
Flat-sheet film is used for tack-used for enclosing metal tubular
frames with a tight double layer of film.
Large plant hoods made from semicircular aluminum or galvanized
steel pipe and fitted with a sleeve of tubular plastic film make
excellent cold frames or seasonal row covers. When used in this
way, a double layer of plastic film provides an air space that
insulates against 4� to 7� of frost temperature change.
Electrically heated plant beds are ideal for the home gardener,
provided electric rates are not too high. The beds may be built
Because they are equipped with thermostatic control, they
require a minimum of attention.
It is now possible to buy frames�completely equipped with
heating cables, switches, and thermostats�ready to assemble and
set in position.
the frames with soil or plant boxes and connect to a source of
current (fig. 11).
Small frames may be removed at the end of the season and
stored; larger frames are usually treated as a permanent
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