Maximum Yield USA December 2019 / January 2020 | Page 36

The peanut plant produces its pods
on the ends of pegs — long stems that
develop from the aerial portion of the plant
after flowering and self-pollination —
then burrow down under the growing
media to develop the young fruit (peanut
seeds inside brown pods).
For this reason, hydroponic systems
for peanut plant production need to
have substrate that is soft, friable, and
light with the surface under the plant
exposed for the pegs to grow down into.
Finer grades of sterilized coconut fiber
or blended coconut fiber and perlite
make ideal substrates for this crop.
Peanut plants need a warm growing
environment with reasonably high light
levels for maximum growth, and good
air flow up and under
the crop as damp
conditions favor fungal
pathogen development.
A well-grown peanut
plant can have up to
40 pods, so a growing
container or bed that
holds at least two
gallons of media is
required when growing
hydroponically. A
standard vegetative
nutrient formulation
followed by a higher
potassium fruiting
formulation during the
pod development phase
at an EC of 1.2–1.6
is ideal under good
growing conditions.
Outdoor peanuts
are harvested when
the foliage begins to
turn yellow and die
back, however, in a
hydroponic system it
is possible to dig back
some of the growing substrate, observe
the development of the young pods, and
determine when the peanuts are large
enough to harvest. Harvested peanuts
then need to be dried inside the pods
in a warm place for about four weeks
before they can be stored.
processed in a spiced pickling solution
to make an addictive snack. There
is a wide selection of gherkin seed
to select from, including varieties
of green- and white-skinned types,
however, the main characteristics to
consider with hydroponic crops are
compact plant size, wide disease
resistance (particularly to mildew),
parthenocarpic plants (fruit set without
the need for pollination and with no
seeds inside), size, and shape. Pickling
cucumbers need sufficient warmth
(60-82°F), moderate to high light levels,
and can be intercropped with tomatoes,
capsicum, and other heat-loving crops.
Since gherkin plants are smaller than
other cucumbers, they can be grown
two to three plants
per planting
space and trained
upwards and along
strings for wires.
Nutrient solutions
should begin on a
standard vegetative
formulation at a
moderate EC of
1.8–2.2 and pH of 5.8.
This should then
be switched for a
fruiting formulation
with higher
potassium levels
for maintenance of
good fruit quality
as soon as the
first tiny fruitlets
have formed, and
maintained until
the crop is finished.
Under hot growing
conditions, the EC
can be dropped
back slightly,
particularly if the
plants are wilting under overhead
lights. Cucumber vines are largely
indeterminate, so they need to be
carefully trimmed and trained to
prevent them taking over the entire
growing area; growth can be directed
upwards to an overhead support and
then downwards again so the maximum
number of fruit can be obtained from a
minimum of vertical space.
The small fruit only take a few days to
develop to a suitable pickle size once
flowering has occurred and need to be
harvested frequently. Fruit can then be
stored in the refrigerator until enough
“ Some keen
pickle makers
also grow various
hydroponic herbs
and spices to
add to their jars
of pickles for
additional flavor,
the most common
being dill for
the famous dill
pickle flavor.”
Pickles
The small pickle cucumber, or gherkin, is
a more compact plant than the seedless
European cucumbers commonly
grown hydroponically and produces
large numbers of crisp, seedless, and
mild fruit that can be eaten fresh or
From the Top: A number of heirloom and gourmet peanut types are available that perform well
in hydroponics; Choosing gherkin varieties with mildew resistance is advisable to avoid common
disease problems; Hydroponic pickles come in green and white varieties of mini cucumber or gherkin;
Sunflower plants grow well in a moisture retentive substrate with frequent irrigation.
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Maximum Yield