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Friendly Aquaponics
Commercial Newsletter

Number 17
May 4th,  2013
Images from our farmily aquaponics farm

The Mysteries of Aquaponics, Part 5: Why Your Plants Will Grow Great On Zero Measurable Nitrates!

We were baffled by our systems growing vegetables so well, even when they had unmeasurable (read: “zero”) nitrates for extended periods of time. Although we aren’t PhD’s, we follow proper scientific procedure to the best of our ability when investigating something new in aquaponics. We look at the data we have, use logic and reason, and try to come up with a testable hypothesis that can explain the facts.


Note: a scientific hypothesis is a proposed explanation of a phenomenon which generally fits the facts, but still has to be rigorously tested before being accepted by the scientific community. In contrast, a scientific theory has undergone extensive testing and is generally accepted to be the accurate explanation behind a phenomenon.


After we formulated this “zero nitrates” hypothesis, we shared the information with our students to determine whether we were the only ones to get these results, or whether they got roughly the same results. This is part of the process by which a scientific hypothesis (untested) is transformed into a scientific theory (tested and accepted to be accurate).


Here are the data and observations we started with:


1. Plants were observed growing explosively and vigorously during (several) extended periods of several months each, in separate large aquaponics systems that each tested zero for nitrates with test kits that clearly show 1 ppm nitrates during the entire duration of those periods.


2. Ammonia levels during these same periods in these systems ranged from 0.25 ppm up to 0.5 ppm, and infrequently as high as 1 ppm; so adequate ammonia for nitrification activity seemed to be present. Ammonia levels never got into the range that is generally accepted to inhibit nitrification (over 3 ppm).


3. Water temperature ranges from 68 to 76 degrees F were observed, as well as DO ranges from 5 to 7 ppm in the fish tanks, and 4-5 ppm in the aquaponics troughs; so the nitrifying bacteria had adequate oxygen, and were in water of nearly optimum temperature for their metabolic and biochemical activities.


4. Nothing besides fish food and chelated iron (to correct iron deficiency in the plants) was ever added to the systems during these periods, or during any other period. There was no other form of available nitrogen being added to these systems that the plants could have grown on.


Rose and Dad and two of our "Delicious Fishes". Although we eat them with respect, we don't give them names because then it's harder to eat them.


Here is our hypothesis:


Our plants were growing vigorously; and plants need nitrates to grow; ergo, we could safely conclude that there were nitrates present. We could also safely conclude that the nitrates must be coming from somewhere in the systems, because we were not adding nitrogen (fertilizer) in any other form to the systems.


Also, even though the fish were fed large amounts of fish food during these periods, which resulted in decaying organic material (fish poop) and which then was transformed into ammonia, we never once saw an ammonia spike or rise in ammonia. Thus, we can conclude that something in the system was converting the ammonia into another form; otherwise the ammonia level would have risen and kept rising. Observation showed it nearly constant at low levels.  


If you can imagine the fish in our fish tanks pooing; and that poo breaking up into microscopically tiny pieces through the vigorous action of the bubbles from the airstones in the fish tank; and then going out throughout our system to get converted into ammonia; then you can imagine all those zillions of bacteria living on the thousands of square feet of plant roots we described in our last newsletter here .


Remember also our numbers from that last newsletter: in a large systems of ours, there was 64,000 square feet of area represented by the plant roots themselves, and only 10,000 square feet represented by the fish tank sides, bottoms of rafts, that is, the “non-root” area. With the bulk of the area available for these bacteria to colonize residing in the root surfaces of the plants, it is logical to conclude that the location where the bulk of the nitrification activity in the system occurs is on the roots themselves. So what are our friendly bacteria doing?


We think they are taking up the ammonia in the water, and turning it into nitrites, then into nitrates, right on the surface of the plant root itself. With that kind of process happening on the root surface, it would be an easy step for the plant root to absorb the nitrates directly as the bacteria make them. It makes perfect sense to us, and explains, without any “gaps” in the hypothesis, why our systems produce incredible vegetables for months at a time with zero measurable levels of nitrates in the water.


This is because the nitrates the plant is absorbing and using to grow aren’t floating freely in the water, so they aren’t measurable when you sample the water; they’re on the plant roots. And when we stick a measuring strip into the water, it is “hundreds of miles away” (on a bacterial scale) from what’s happening on the roots, so of course it doesn’t measure the nitrates being created by the bacteria on the roots, and then being absorbed there immediately by the plant.


To demonstrate how universal this phenomenon is (in organically operated aquaponics systems), consider the following example: during our recent Texas training at Sand Creek farm (thank you Ben and Alysha Godfrey for being such gracious hosts), we sampled the water in their three aquaponics systems with very sensitive test strips. One system showed 3 ppm, one showed 5, and one showed zero ppm nitrates; all three systems were growing vegetables beautifully, even though they’d had some 20-degree nights, and they had very simple poly-covered greenhouses.


(Next week we’ll talk about something technical, and interesting, about aquaponics. Thanks for listening!)

Friendly 2014 Commercial Aquaponics and Greenhouse Training Schedule:

California Training from May 29th-31st, 2014

Texas Training from May 5th-9th, 2014

Tennessee Training from April 28th-May 2nd, 2014

(Below) One of
Ben and Alysha Godfrey's aquaponics systems in a greenhouse in Milam County, Texas. Their system water tastes great! It has a pale blond hue, with a hint of apple and pear blossoms.

(Below) Another of Ben and Alysha's aquaponic greenhouses.

(Below) Tim drinking water from one of Randy and Katie's aquaponics systems at a Tennessee training. "I've been doing this for six years; I'm certain the food from these systems is safe and healthy" (Tim).


These five-day trainings allow you to travel during the weekend so that you only need to take a week off your busy life to attend, and include our $999 DIY Commercial Aquaponics package, $998 DIY Farmer's Market Aquaponic Solar Greenhouse package, and new $295 DIY Commercial Tilapia Hatchery manual as course materials, plus our Plywood/Epoxy/ Tank manual, CAD construction drawings for all greenhouses and aquaponics systems, and much more!

(Below) Randy and Tim showing attendees at a Tennessee training how easy it is to use a DO (dissolved oxygen) meter to measure oxygen levels in the vegetable troughs.


More details of the Aquaponics Technology course here.

More details of the Aquaponic Solar Greenhouse course here.

More details of the Commercial Aquaponics course here.

(Below) Randy and Katie's Chinese-style Aquaponic Solar Greenhouse in Tennessee in the February snow, 2013. 70 degrees inside and you had to take your coat off when working with the vegetables!

GreenhouseSnow3Small 2

An Aquaponic Solar Greenhouse with the participants in our second June 2013 course in Tennessee!

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The Friendly  Aquaponics Way Video!
Back Issues Of Newsletters Now Available, Click Here!
Trough Liner Distributors:
West Coast USA
East Coast USA

Click here for Trout fry and fingerlings directly from the hatchery to you!


Sign yourself up for the Tennessee

Or the Texas

Or the California

April/May 2014 Commercial
Aquaponics and Solar Greenhouse Trainings
NOW, and receive a free Micro System DIY package so you can begin studying aquaponics, as soon as you register! ($99.95 value)

Spanish Language Micro System package now available!
Free Farm Tours

Aquaponics tour at the Friendly farm!

We hold a free Farm Tour on our farm the FIRST Saturday of every month at 10:00,  focused on growing food with aquaponics.  Click here for information. See you there!

If you are a school, a non-profit organization, an organization working with the poor, Native Hawaiians, or ex-inmates, or if you are a church, we will hold a free farm tour for you anytime. You DO need to email us first to schedule, or we might be out on errands!


Thousands of inch-long "fifty-cent" baby tilapia from our "backyard" hatchery.


What they turn into about a year later: a beautiful 2-pound white tilapia grown in the fish tanks of our aquaponics systems.


Micro System Classes!

Our four affiliates are now offering Micro System courses.

Click here
for a listing of affiliates and course locations!


Our new book: "Aquaponics The EASY Way!" is done!

It covers how to successfully build and operate tabletop aquaponics gardens from 3-1/2 to 18 square feet in size, using materials and equipment you can buy locally at Home Depot, Lowe's, and Petco.

The "3.5" costs you under $100 in Hawaii (where things are expensive) and the "18" costs $320.30. Click here to get our free "System Cost Calculator", an ExCel spreadsheet that you can put your own local numbers into (for parts) to find out what your system will cost you.

To purchase this E-book for only $29.95, click here. It's an excellent textbook for aquaponics for students from 6th grade on up. If you are a teacher, school administrator, or other faculty member, email us for information on pricing and volume discounts for textbook use.

The "Spice Chronicles", #4: "Nuku Hiva North Point Mixup"

This is a fish story from 1976, when I was sailing my 37-foot cutter "Spice" in the Marquesas Islands (down near Tahiti). I had made a plan with some friends on another cruising boat to meet them in a small bay on the North side of the island of Nuku Hiva.


They'd left Taiohae bay earlier in the day, and I'd stayed to finish some maintenance jobs on my boat. I got done later than I'd expected to, hauled anchor and set sail for the north side. I had put out four trolling lines as soon as I'd cleared Taiohae harbor, but hadn't had a single strike in about an hour and a half of sailing.


As I made my way around the western end of the island and turned north, I watched my lines and wham! One of them went off, the bungie cord stretching all the way out to its full length of six feet. This meant that there was a big fish on, and I sheeted out and put the boat on her windvane self-steering so I could  go pull the fish in.


I pulled in a nice 50-pound yellowfin tuna, what was called locally "kahi", and put it in a net bag. I then put out the trolling lines again, and got headed in the right direction.


Just as we were passing around the north-western tip of the island, the wind, which was blowing straight towards the towering 500-foot black stone cliffs that came right down into the sea, switched and came FROM the cliff for a minute or two. It swirled around the boat, throwing us aback, with the sails pressed against the rigging and mast.


The wind wasn't very strong, and we were VERY close to the cliff, so (just a little scared!) I jumped down below and started my little hand-cranked 6-hp diesel engine to get us straightened out and go in the right direction.


In my little time below, though, we'd gotten a gust of wind that had swirled the boat around, and as soon as I started the engine, the prop sucked in a couple of the trolling lines and the engine stopped dead with the lines wound around the prop shaft. Now I was really scared!


I looked at the wind, saw that it was gusty and shifting from moment to moment. I saw the cliff, only about 200 feet away now, and realized that I was at a critical juncture. So I sheeted the sails all the way out (loose), dropped the boarding ladder off the stern, and dove over the side with a razor sharp butcher's knife in my hand.


The whole time up til now I had kept my lifeline harness and lifeline on, to keep me with the boat, but now having a webbing harness and line on me could be the one thing that caught on a rudder gudgeon or the prop itself and drowned me. So I dove over without any lifeline on.


I went straight under the boat, and sawed about half the lines off the prop with my first breath. I had to come up to take another, then went down again. There was a confused sea off the point, and although the boat wasn't moving through the water much, or at all, she was bouncing up and down three or four feet on the stern and trying to bash my head in with the rudder and propshaft.

When I went under and grabbed the propshaft as a solid point to work from, I was jerked violently up and down underwater about every four to five seconds, which was the period of the waves.


I went down a second time, got a death grip on the propshaft, and just barely sawed the rest of the lines off the shaft before running out of air. Swam to the boarding ladder, faced a quandary:

How do I climb this thing with one hand holding onto a knife? Jammed the knife in between my teeth like a buccaneer, latched onto the ladder like it was my savior (it was!), and made it up the three rungs in about three tenths of a second!


The engine had never sounded sweeter when it cranked over and sucked me and my boat away from the towering stone cliffs. I sailed into the bay without seeing a sign of my friends; kind of feeling my way because by now it was pitch black, and there were no boats, no lights on shore, and no moon out.

When I got the boat anchored and collapsed into my bunk, I totally forgot about the beautiful ahi I caught, and had to salt-dry it the next day instead of eat it fresh. But I still had a boat!

Aloha, Tim.....

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