Maximum Yield Australia/New Zealand November/December 2018 | Page 34

“ TOMATILLOS
can be grown alongside
tomatoes and chilies in the same nutrient
solution as these all prefer similar warm
temperature conditions with an optimum
of 26°C and moderate to high light levels.”
Most tomatillo varieties will need support as these grow to
a similar size as large capsicum plants (up to five feet) and
will produce a profusion of husked fruit. It’s also advisable
to grow at least two to three tomatillo plants in a closely
spaced group to assist with cross pollination. Fruit are
ready for harvest when the husk turns a papery tan and
starts to split open at the sides.
CHILIES
Chili peppers originated in Mexico and Central America and
the fruit provide not only heat of varying degrees, but also
intensive colour, flavour, aroma, and texture, making them a
very versatile plant. While there are number of Mexican chili
types, the main varieties grown hydroponically are habanero,
poblano, mulanto, and jalapeno. The heat experienced from
eating chilies comes mainly from compounds called capsa-
icinoids, although other pungent compounds have been iden-
tified in hot capsicum fruit. What gives hydroponic growers a
major advantage when it comes to growing Mexican chilies is
the pungency of the fruit, and even the flavour, can be manip-
ulated somewhat by the growing conditions provided. The
concentrations of capsaicin in the chili fruit increase with
plant stress factors such as a lack of moisture, high tempera-
tures, high electrical conductivity (EC), and high salinity.
Capsaicin concentrations also increase throughout the devel-
opment of the fruit and are always highest at maturity. So,
allowing chilies to ripen and fully mature on the plant (even to
the point of starting to shrivel) will maximise the heat factor.
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Beefsteak tomatoes with a high solids content are the mainstay of
many Mexican dishes.
Chili plants can be grown in a wide range of hydro-
ponic systems, although media-based systems are most
commonly used as some chili types can grow into large
plants at maturity. For NFT, the smaller, bush types of chili
are often a better choice and these may need support if
the plants become tall and lanky under low light. The best
way to obtain plants is to raise these from seed, which
germinates readily between 22-28°C in an inert media
such as stonewool or small pots which can be later trans-
planted into the hydroponic system without too much root
disturbance. After germination, seedling temperatures
can be reduced back to 20-25°C and light levels gradually
increased to harden off seedlings before transplanting.
For strong flowering and fruit set, the night temperature
should be a little lower than the day temperature with
an optimum of 25°C during the day and 18-20°C at night.
Chilies, while self pollinating, do benefit from some polli-
nation assistance such as gently tapping or shaking the
plants when in flower to help release the pollen.
Most chili types perform well in standard grow and bloom
hydroponic nutrient products. Electric current levels should
be between 0.8-1.0 for seedlings, gradually increased to
an EC of 2.0 before planting out. For those looking to inten-
sify heat, increasing the EC up above 3.0 and allowing the
growing media to dry slightly between irrigations will help
concentrate flavour and heat in the fruit, but may reduce
yields somewhat by lowering fruit fresh weight.