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GrowingYourGreens.com Aquaponics No Ka 'Oi Video with John Kohler
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Aquaponics No Ka 'Oi, established in 2010.  A small Mom & Pop backyard urban farm in Kahului, Maui, Hawaii.  Less than 3 food miles (less than 10 minutes) to Down to Earth in Kahului.  Guaranteed fresh.  Local.  Certified Organic.  Non-GMO.  No chemical pesticides.

"No ka 'oi" means "is the best" in the Hawaiian language.  "Maui no ka 'oi" has been a common saying for as long as I can remember growing up on Maui.  Thus, Aquaponics no ka 'oi.  A compact system that attempts to emulate the ecosystem found in nature to abundantly provide food for mankind.  An integral part of the higher goals of permaculture and sustainability. 

 Here's what our covered growing troughs look like.  As you can see, birds, animals, and most insects are kept out with the netting.

Feed the Fish, and the Fish feed the Plants.  As most of you know, in aquaponics, the fish water provide most of the fertilizer for the plants.  The fish wastes in the form of ammonia are broken down by nitrifying bacteria (nitrosomonas, nitrobacter, nitrospira which convert ammonia to nitrites, and then to nitrates, plant food), gammarus (detritivores which eat fish waste solids and decaying organic matter to break down the micronutrients and minerals for easier plant uptake).  Sometimes compost (red) worms are used in the cinder based biofilters to add worm castings to the nutrient mix.  Unlike hydroponic water, aquaponic water is alive with diverse micro-organisms.  Therefore, toxic chemicals cannot be used for fear of harming the fish and the microbes.  It should be noted that our system water has been tested in a certified laboratory and found to contain no E. coli, which are only found in warm-blooded animal waste.  Fish are cold-blooded and do not contain E. coli.

Aquaponic water contains the Four Principal Components of SoilAir, Water, Organic Matter, and Mineral Matter, although not the Texture (sand, silt, and clay) and Particle Sizes of dirt.  The plant roots in turn, absorb the nutrients from the water, cleansing and filtering it to recycle the water back to the fish.  On our farm, aquaponic water helps to replenish the soil microbes outside of our aquaponics system.

We sell vegetables, not fish, but the fish play a very important role in this ecosystem, and sometimes they get too big or too many, and need to be culled to maintain the balance of the ecosystem.  This provides another food source to the community for those that like tilapia.  This particular breed of fish (Oreochromis niloticus, the White Nile tilapia) is self-perpetuating.  In 2011, we started with 5 white tilapia, and had a hatch of about 3,000 fry.  Since that time, we have never needed to obtain any more fish for our system.  Here is a picture of Kalewalani, a University of Hawaii student who was doing research on aquaponics for a presentation (she got an A!), and helped to cull the system and take food home for her family (see Talk Story for more on her).

 

Why is an organic farm in the center of Kahului such a big deal?

Well, look at it from my perspective.  I was raised in an Upper Paia sugar plantation camp called Nashiwa Village, close to Paia School, just below the Holy Rosary Catholic Church.  This was a thriving community back in the 1940's & '50's.  We used a 4-door outhouse that shared a cesspool with 4 neighbors on the 4-corners of the lots.  Open grey water ditches ran between houses, our drinking water system used a Bull Durham tobacco bag over the faucet for a filter and got muddy during rains.  The plantation sprayed DDT in the air frequently to control mosquitoes.  My Mother used a large metal tub with a wooden paddle over an open fire to wash my Dad's really oily clothes from working as a mechanic in Paia Mill.  The plantation owned everything, the house, the land, our healthcare, and even us.  The land was fertile, and most everyone had a garden.  Fruit trees grew wild everywhere, and there seemed to be no lack of freely accessible food.

Then in 1960 we were enticed by A&B, the plantation owner, to relocate to the 6th increment subdivision of Kahului (currently that older subdivision across Ka'ahumanu Avenue from Maui College) close to the "Dream City" development.  The plantation wanted Upper Paia back to grow sugar cane and to cut back on the expense of maintaining the plantation camps.  The 6th increment was non-arable land built on sand dunes.  The land was offered to us at the affordable price of 25 cents per square foot.  What a deal.  The 6th increment was scraped of its top layer along with the kiawe trees  right down to the bedrock of pure sandstone.  I helped my Dad build the house that we currently live in with the help of friends and family.  I later found that the pH of the "soil" was 8.4, pure coral sand.  I remember helping my Dad try to crush the sandstone with pick and shovel for years to make a plantable top soil.  My Dad came from a pineapple sharecrop family in Ulumalu before working at Paia Mill so he wanted to make things grow for food.  Solid sandstone is pretty hard stuff, it will bend your digging tools.  We also hauled truckloads of dirt and manure from Paia and upcountry to try to make the soil more arable.  To some extent we succeeded, but the land has a tendency to go back to its native bedrock, sand, which is also a pH buffer.  Plus where we lived, sand was always blowing over the land, creating sand berms and burying the more organic soil that we built up.  It was a losing battle.  But I never lost my connection to agriculture.  I picked pineapple for five summers around my high school years, and I swung a cane knife as a seed cutter (cutting 18" lengths of cane stalk) in the cane fields of Puna Sugar on the Big Island in the early 70's between attending Hilo College.

Of course there is a lot more to this story, but just let me say that I have never seen this land thrive with abundant plant life until I installed this aquaponics system.  I also use the fish water to periodically fertilize my in-ground fruit trees.  Between our chickens and the fish, the soil on our land is becoming more organic and microbe rich.  I believe that this is the future of small scale urban agriculture as we lose our arable land and water resources.  The more people that do this on Maui the better.  I see an agricultural cooperative where a lot of smaller urban and traditional farmers will be able to provide for much of the food needs of Maui and decrease our dependence on imported foods.  If it can be done in Kahului, it can be done anywhere.

Meet the Farmers

Patty (Mom) & Larry (Pop) Yonashiro.  Born in the plantation camps, and raised on Maui.  Now retired.  Four daughters.  Five grand kids.  We actually spent about 34 years away from Maui before returning in 2002 to care for our Kupuna.  Larry left Maui in 1968 for a stint in the military and Vietnam, and Patty left in 1972 to finish college and received her BS degree in nursing from the University of Hawaii Manoa.  Part of our time away, Larry spent working as a civilian for a Department of Defense contractor overseas.  One daughter was born in Honolulu, one in Yokosuka Japan, and two were born in Okinawa.  We then lived in Seattle for four years, Dillingham Alaska for ten years where Larry was the CIO (Chief Information Officer) and Patty the CQI (Continuous Quality Improvement) nurse for an Alaska Native Tribal hospital (this is where our kids grew up and consider home), and Longmont Colorado for three years (where Larry contracted with IBM in Boulder)  before returning to Hawaii on a family emergency (IBM kindly allowed Larry to work remotely in Hawaii operating a Help Desk from home for another 8 years up to 2010) while Patty took care of her bed-ridden mon.  Patty is a Registered Nurse (BSN, University of Hawaii) with experience in CQI for Joint Commision hospital accreditation, and she also has a second BA degree in English Literature.   Larry has a degree in business and management from the University of Maryland, up to senior level coursework in electrical engineering (UH College of Engineering), and a graduate certificate in Information Systems Management from City University in Bellevue Washington.  The decision to retire early was motivated in part by the desire to get as far away from our professional lives as possible, and to get back to nature.  Aquaponics provided the way.

Mission

To provide the highest quality, best tasting, and healthiest produce in a clean and safe environment, to prove the concept that a small urban farm can be economically viable and sustainable using the right methods and technology, and to encourage others to do the same.

Vision

Many small urban and traditional local farms working together in an agricultural cooperative to provide healthy foods for much of Maui to reduce our dependence on imported foods and to provide a backup source of food in the event of a disaster.

Technical Details of the Current System - Updated 10/27/16

Our system type is a Deep/Direct water culture (DWC) aquaponics system composed of five 32' x 1' deep hydroponic troughs connected in series.  Each trough holds  about 900 gallons of water with sixteen 2' x 4' floating rafts per trough.  Each floating raft has thirty-eight 2" holes to hold 2" net pots filled with a 60/40 percent mixture of coir/vermiculite respectively, plus the seedling, giving a potential of 3,040 heads of produce in the system at any given time, at various stages of development.

Total growing space of the system is 640 square feet (ft2), calculated by 16 rafts/trough X 5 troughs = 80 rafts total.  Each raft is 2' X 4' = 8 ft2 x 80 rafts = 640 ft2 total growing space.  Total agricultural acreage is calculated at less than 0.1 acre including the walking areas around each trough,  and the fish tank areas.  Total current output of vegetables is 2,080 lbs/year at 40% production.  Estimated target output at full production is 5,200 lbs/year for 0.1 acre.

Total water capacity of the system is calculated as 5 troughs x 900 gallons/trough + 3 fish tanks x 300 gallons/tank = 5,400 gallons total.  Note that I also have a separate green tank (algae) to breed and hold tilapia that has about a 1700 gallon capacity.  The water is recirculated, and the loss due to evapo-transpiration is about 300 gallons per week (5%), replenished with de-chlorinated city water.  The system uses one MD7 Danner water pump (60 Watts continuous), which moves 300 gallons/hour up 2' to the fish tank, and then uses gravity flow to move the water through over 160 feet of trough and pipe space back to the pump.  A spare MD7 is kept to quickly swap out the bad water pump for a good one.  This has easily been done as a test, since the pump has not failed in 3 years.

The system holds about 300 lbs of tilapia in three tanks to produce fertilizer for the plants.  Biofilters utilizing volcanic cinders to provide surface area for the nitrifying bacteria, gammarus (in the lower part of the filter), and red worms (in the upper parts of the filter) to break down the fish solids and add to the nutrient mix for the plants.  Two biofilters between the 3 fish tanks are composed of nylon scrubbing pads to provide surface area for the nitrifying bacteria and housing for the gammarus.  These catch and break down fish solids.  Water quality and clarity is controlled by increasing or decreasing the feeding and monitoring the water chemistry.

Typical water chemistry is 0.5 ppm Total Ammonia, 1.0 ppm Nitrite, and 160 ppm Nitrate.  Although these readings are not "ideal", the fish (Oreochromis niloticus) show no signs of stress, and the vegetables seem to do best at these levels (note that this has been tested at my site only, and may not work at your site).  The pH is controlled with Crushed Oyster Shells (calcium carbonate, CaCo3, OMRI listed, Organically Certified) to provide the  buffer, and is typically held at 6.5 pH.  Kale seems to be the largest consumer of iron, and is the first to show signs of iron deficiency (interveinal chlorisis).  Chelated iron (Biomin Iron, OMRI listed, Organically Certified) is added when iron deficiency is noted.  Kale and lettuce may show signs of potassium deficiency through stunted growth, chlorosis, and leaf edge necrosis.  Sulfate of Potash is added (K2SO4, OMRI listed, Organically Certified) to address the potassium deficiency.

As always, the health and mood of the fish are the primary indicators that something is right or wrong with the water quality/chemistry.  The fish seem to be fine with these organic additives at their current levels (not all organic additives are fish safe).  Note that it takes up to 2 weeks for any stress (primary cause) to show up as a sickness (secondary infection) in the fish.  Healthy fish exhibit vigorous feeding habits, and a calm peaceful swimming patterns after feeding, with no gasping at the surface or lethargy.  Always select a strong breed of fish to use.  We tried raising the red/golden tilapia (Oriochromis mossambicus) for one year, and experienced too many sicknesses and deaths to make it worthwhile.  I currently only raise the White Nile (Oriochromis niloticus) variation that is strong and hardly gets sick.  Note that I've also made the decision to use fish primarily to produce the fertilizer for the plants.  Of course, periodic culling of the tilapia is done to keep the population in check, but that is secondary to vegetable production.  I tried to raise tilapia as my primary output, but that did not work.  Maintaining water quality became too costly and difficult with a large amount of fish in the system.  Therefore, vegetables are my primary output.  The White Nile tilapia are prolific breeders.  We originally started with 5 White Nile tilapia in 2011.  A hatch in 2011  produced about 3,000 white and dark offspring, and we have never had to obtain any tilapia since.  These things are self-perpetuating. 

Air is supplied to the system by 4 airpumps: 2 Hakko 60L, 1 Whitewater TL66, and one TL66 left unplugged for a spare.  Testing revealed that running 4 air pumps in parallel did not create much of a difference than 3, and the increased back pressure is known to wear out the diaphragms sooner.  Note that this only related to my design.  Other designs may require a different number of pumps.  The pumps (outdoor rated) connected in parallel to a distribution system of 1" PVC pipes, barbs, and airstones to the fish tanks and troughs.  Dissolved oxygen (DO) is measured at about 4-6 ppm at the troughs and fish tanks.  The four air pumps (including the unplugged spare) all connect through check valves at their outputs to the distribution system so that if a malfunction occurs, air will not flow out while the other pumps will continue to supply air to the system, albeit at a lower output.  The spare pump is kept to quickly connect to the system in the event of a failure of one of the other pumps.   Repair kits are also kept to fix the defective pumps.

Electrical power is supplied to the water and air pumps through a Xantrex PowerHub 1800, which contains four 88 Ah medical grade gel batteries.  The batteries currently uses power from solar panels (net metering) and the grid for charging (at night), and uses a built-in inverter to supply power to operate the air and water pumps.  When a power outage occurs, the batteries will continue to run the pumps for 5 hours (actual test).  After 5 hours, a generator can be connected to the Xantrex to continue to charge the batteries if the outage is prolonged.  The generator is a Honda 1000i, and has been tested to run over 10 hours on 0.8 gallons of gas.  The generator is tested monthly.  The Xantrex currently uses electrical input from the solar panels and grid, but can also take input from wind turbines in the future.

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Here are some images of our backyard in Kahului.  We started building our system in 2010.  See "Talk Story" for more information.

Click on an image to enlarge and start the slide presentation.

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