ASK THE EXPERTS
Q I HAVE
been experimenting with an outdoor
hydroponic system using different types of
stonewool and it hasn’t been a raving success. I now understand
that I need a drip or flow system rather than manually watering
once a day, and bugs decimated my pea crop before I understood the
problem. I’ve been looking into aquaponic systems, which seem expensive
when compared with hydroponic systems. How much longer does it take to
break even with aquaponics versus hydroponics and what is the difference
in start-up costs? It will still be outdoors as I am several years away from
setting up any kind of a greenhouse. I live in New Mexico.
THANKS, LOUISE CHRISTENSEN
You should take
comfort in the
fact that there
are literally tens
of thousands of
people scratching
their heads over
these exact problems right now. If
you’re very quiet, you can even hear
the scratching. You’re correct—
aquaponics does have a higher
start-up cost than hydroponics.
Building your own system using a
manual such as the IBC of Aquaponics
or the Zero to Hero System will minimize
your costs and save your sanity, but
there’s no way to get there without
spending at least a few hundred
dollars. Purchasing a pre-fab system is
likely to cost thousands of dollars.
A
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Maximum Yield USA | September 2015
Then you get into challenging questions such as whether to shut down
in the winter, move indoors or build
a greenhouse. An article on my website, frostyfish.com, titled “Aquaponic
Economics” can help you think about
those choices. I grow year-round here
in Wisconsin, so I know that year-round
growing can be done cost-effectively.
Assuming a reasonable food cost (half
of farmers’ market prices), a system
built according to one of the plans
mentioned above can achieve a payback
of two years, not including your labor.
This estimate, however, assumes you
won’t kill any fish (which you will). How
close you come to a two-year payback
depends on how careful you are, and
how much you learn beforehand about
how to operate it.
There’s a hot debate about whether
you can grow faster in aquaponics or
hydroponics. University researchers in
Australia and Canada have both shown
aquaponics achieving faster growth in
side-by-side tests with much larger root
systems, but hydroponic system designers raise legitimate concerns about the
“THERE’S A HOT DEBATE
ABOUT WHETHER YOU
CAN GROW FASTER
IN AQUAPONICS OR
HYDROPONICS.”
test methods. At the end of the day, it’s
reasonable to suggest that they’ll achieve
similar growth rates.
Comparing the cost per gram of nutrients, hydroponic powders are cheaper
than fish food. However, aquaponics
makes a lot of sense if you want to raise
your own fish to eat. For me, a fresh trout
dinner is the best part of my garden. It’s
also fun when the neighborhood kids stop
by to feed my fish and test the water.
As for your pea plants, I don’t know what
kind of bugs ate them, but I can tell you
that most aquaponic gardeners manage
pests with beneficial insects like green
lacewings and ladybugs. My green lacewings are beautiful and have a great sense
of humor. I read Douglas Adams aloud
to them, and they would laugh if their
mouths weren’t so busy chomping aphids.
CHEERS, JEREMIAH ROBINSON
Jeremiah Robinson lives two lives. By day, he’s an energy efficienc 䁕