Recoil Offgrid – August-September 2019

ISSUE 32

OFFGRIDWEB.COM 047

3. An investment
   of less than $30
   can provide
   enough pre-
   mixed fertilizer to
   create up to 200
   gallons of nutri-
   ent solution.


4. A float system
   can work well
   in a home-scale
   operation.


5. The Kratky
   non-circulating
   method doesn’t
   require a lot of
   equipment.


6. Lettuce and
   tomatoes are two
   crops that do well
   in hydroponic
   culture.

HYDROPONICS

BASICS

containers, and quite a few complete kits can be found

online in the $100 range.

Which Crops?

Almost any crop can be grown hydroponically, in theory,

although maturity days and plant size can make some more

challenging than others. For this reason, crops most often

seen in hydroponic production systems include herbs,

tomatoes, peppers, cucumbers, celery, watercress, and leaf

lettuce. A brand-new hydroponic grower would do well to

start with one or two of these.

Strawberries can also do very well hydroponically. The

advantages include removal of the crop from exposure to

soil-borne pests and the labor benefits of picking berries

that are elevated above the ground. Hydroponic strawberry

production has proven to be a viable method in some arid

parts of the world, including desert regions of Israel.

The Simplest Method

A technique developed by Dr. B.A. Kratky of the University

of Hawaii makes hydroponic growing accessible to more

people by removing pumps and electricity from the equa-

tion. The “Kratky Method” is a non-circulating system that

can be housed in a plastic bucket or tote.

“The suspended pot, non-circulating hydroponic method

is a convenient way to grow short-term vegetables like

lettuce and pak-choi,” Dr. Kratky explains, “because a small

tank containing

Because light requirements don’t change, it’s also untrue
that you can space hydroponic vegetables closer than you
can in a garden plot. (Spacing plants too closely in either
scenario can be an invitation to not only poor production,
but also to spread fungal diseases from plant to plant.)
Taste and nutrition of the final product will be similar
between the two systems as well, provided that each
plant has access to the required amounts of light, oxygen,
nutrients, and water. For any who have been less than
impressed by a hydroponic tomato or other vegetable, that
could be blamed on a simple missing nutrient.
Growing hydroponically can be rewarding, but it doesn’t
require less work than conventional gardening — just
different work. No, you won’t have to hoe, plow, and dig, but
you’ll need some basic plumbing knowhow, and you may
become more of a chemist than you planned to be.
Furthermore, while the commercial hydroponic operations
you may have seen are constructed in greenhouses and
under artificial light, this doesn’t have to be the case. It’s
possible to have a system on your patio or in a south-facing
window, where growing can take advantage of natural light
and temperatures, following roughly the same growing
season as a conventional garden.
You can spend as much money as you want on
hydroponic gardening (as with most hobbies), but it
doesn’t have to be expensive. It’s possible to buy enough
equipment for 25 to 30 plants (nutrients included)
for under $50, provided you use recycled buckets or

Nutrient

Deficiencies

If plants are deficient in ...

... then the symptoms are:

lower leaves are yellow;

rest of plant is light green; leaves small

lower leaves yellow between veins; red

or purplish color on leaves

papery and mottled leaves; dead areas

on leaf edges and tips

newer growth (shoots and leaves) dies;

hooked leaf tips

lower leaves with green veins, but

yellow elsewhere;

puckered leaves

papery leaves;

leaf veins darker than

surrounding tissue

Nitrogen

Phosphorus

Potassium

Calcium

Magnesium

Zinc

Sulfur

Iron

Copper

Manganese

Boron

Molybdenum

Cobalt

Chlorine

stunted and spindly plant; young

leaves pale green

veins darker than surrounding tissue;

edges and tips of leaves die

leaf edges dark green or blue;

leaf edges curl upward

dead spots on newer leaves;

leaf has “netted” appearance

stems brittle;

young leaves scorched at edges

leaves deformed and stunted

reddening of leaves and stems;

stunted growth

leaf wilt; leaf mottling