Agriculture Reference
In-Depth Information
3
Cultural Practices
and Environment
PLANT SPACING
Plant spacing is determined by the size of the mature plant. You must con-
sider the actual floor area as the basis for your plant spacing. For example,
if you have a small hydroponic unit of dimensions 2 feet by 4 feet that gives
you a total area of 8 square feet. Tomatoes require 3.5 to 4 square feet per
plant, but that is floor area. You may think that you can only locate two
tomato plants in the hydroponic unit, but not so. The roots of most plants
can be contained in fairly small areas as long as they receive adequate
oxygen, water, and nutrients. In reality you could grow up to eight tomato
plants in those 8 square feet of the hydroponic system. But you must train
the plants outward in a V-cordon method so that at the top of the support
cables the total floor area occupied by those eight plants under your lights
would be equivalent to 28 to 32 square feet. That would give the plants
adequate spacing so that light could enter the canopy and you would have
sufficient access for training the plants.
Peppers and eggplants require similar spacing although their training is
somewhat different as will be discussed shortly. You can plant some pep-
pers and tomatoes together in the same hydroponic system. Perhaps the
best would be peppers on one end and the tomatoes on the other; do not
mix the plants within the row as that may make training more difficult.
Cucumbers (European) require more area, generally 10 square feet per
plant. Their leaves are very large, including the lower ones, so you could
not grow as many plants in the system. The maximum would be about four,
which is half the number of tomatoes, peppers, or eggplants. Four plants
would need to be trained so that they occupy 40 square feet of floor area.
Lettuce needs to be spaced according to the actual area of the hydro-
ponic system. Lettuce should be spaced either 6 × 6, 7 × 7, or 6 × 8 inches
(Figure 3.1), depending upon variety. Bibb or buttercrunch varieties can be
space closer than looseleaf or oakleaf types.
Herbs can be spaced fairly tight. Depending upon their final growth
habit they may be spaced 3 × 3 inches or 4 × 4 inches according to the area
of the hydroponic unit. Remember to sow up to 10 seeds per cube or direct
seed in clumps. Basils and arugula are grown in bunches of 5 to 6 and 10 to
12 plants, respectively. These bunches are spaced at 6 × 6 inches centered
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