Agriculture Reference
In-Depth Information
Temperature control. Don't confuse light with heat. Cool-weather crops, such as
Chinese broccoli and snow peas, like sun but not heat. If you grow them on a rooftop
or terrace, the surface on which they stand may get very hot. After a couple of weeks
of very hot, dry, and possibly windy weather, your plants will begin to look stressed.
Protect them either by moving them to partial shade or by creating partial shade over
them. Plant caddies with casters make it easy to move even big containers. If moving is
impractical, cover with a row cover. Or construct movable lath walls tall enough to cre-
ate partial shade for part of the day. Build them with horizontal wooden bases designed
to keep the walls from blowing over.
Indoor lighting. Plants in a sunny windowsill can get too much sun and heat at certain
times of the year. That's easy to control with gauzy curtains that you draw when the
sun is strongest and brightest (which isn't necessarily high noon), then open so the plant
gets the maximum number of sun hours.
In the winter, or in windows that don't get full sun, use fluorescent tubes to sup-
plement available light. Vegetables that set fruit usually won't produce under fluores-
cent light alone. If you want a plant to set fruit, you must provide sunlight plus enough
supplemental light to make up whatever hours are lacking. In the short winter days of
northern regions, even a window with good sun exposure may not be enough. Ordin-
ary fluorescent bulbs are good enough for starting seedlings or growing leaf crops, but
for eggplants and peppers you'll need the wide-spectrum bulbs (grow-lights) available
from garden suppliers.
Garden-supply catalogs offer fixtures designed to reflect maximum light and pul-
leys that make it easy to raise and lower fixtures. Any fluorescent light fixture should
be movable. For a large fixture, the simplest method is to hang it from the ceiling by a
chain that can be raised and lowered by its links. You'll need to raise and lower lights
to accommodate different-sized plants. For starting seedlings, lights need to be just a
couple of inches above the seedlings, and the lights have to go higher as the seedlings
grow higher. If you're keeping peppers coming on a mature plant, the light has to be
much higher to clear the top of the plant.
Seedlings are very sensitive to low light levels and quickly get tall and spindly as
they reach for better light. Don't let that happen or the plants will always be weak. Ad-
equate light is just as important to immature as to mature plants; it's not an ingredient
you can skimp on. (See page 201 for more about starting seedlings.)
Invest in a timer. Set it to turn the lights off and on automatically, adjusting the
schedule as needed.
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