get their nutrients from the nutrient
solutions added to water. The absence of soil in growing means that
hydroponics systems must have
some way of supporting the plants
while still allowing the bare root
system maximum exposure to the
nutrient solution.
Often a “growing medium” is used
for support and to aid in moisture
and nutrient retention in hydroponics growing. Because they lack media to store water and nutrients,
water culture systems need a continuous flow of nutrients to prevent
drying out the plant roots.
Plants need an energy source in
order to grow. With hydroponics
growing this energy may come
from natural light, which has the
full spectrum of colour or through
the use of different types of artificial lighting (grow lights), which
can be selected for specific plant
varieties and optimum plant growth
characteristics.
With garden production unit,
source of energy derived from natural light whereas with commercial
production unit, source of energy
derived from artificial lighting
(grow lights).
Basics of hydroponics
To be able to produce vegetables
successfully year after year, one
needs to be familiar with the basics
of hydroponics in term of the plant,
growing medium, water and nutrients.
Which crops can be grown in hydroponics?
Basically all high value crops can be
grown. Popular in South Africa are
tomatoes, cucumbers and peppers
in drain to waste systems and lettuce and herbs in gravel flow systems.
Where can you buy seeds?
Seeds are available in small or large
packages. Small packets are sold at
nurseries, co-ops and retail stores
and are suitable for garden – and
small-scale hydroponic units. Large
Differences between hydroponic vegetable production and soil
production
packets, suitable for commercial
scale production are available from
seed companies.
Taking care of plants
Different crops are planted at different spacing. Small-growing
plants can be planted close to each
other. Large-growing plants need
more space to grow and must be
spaced further apart.
• Water flow must be checked every day and adjusted when necessary.
• If plants turn yellow, it is normally a symptom of nutrient deficiency, too little light or a disease.
• Inspect the leaves every day for
disease symptoms and insects. Act
immediately if a problem occurs.
• Tall plants need to be trained and
pruned to make optimal use of the
expensive greenhouse space.
Using hydroponics systems, mineral
nutrients are dissolved in water and
feed directly to a plant’s root system allowing the plants to focus
their energy into growing mostly
upward, promoting quicker
growth, faster harvests and higher
yields. Hydroponics systems are
used year-round both indoors and
outdoors for growing herbs, foliage
and food items. Hydroponics set-up
do not use soil but instead, use an
inert growing medium to anchor a
plant’s roots.