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Plant Rafts with Sprouting Blocks

I utilize six plant rafts, each 4’X6’, for a total of 144 square feet of growing area. Each tank has room for three 2’x4’ polystyrene 1” thick rafts. Each raft has 27 one-inch holes made to accept rock wool sprouting blocks. These are commercially available on Amazon or most hydroponic source stores online. Each block will hold several sprouted plants (if you want to grow multiples on the block) or a single sprout if you prefer. Larger plants, like cabbage, take more room between plants than vertical growers, like tomatoes. Fully planted with (for a new set up) lettuce plants, you can have 487 plants in the system at one per wool cube. This system will produce as much food as one acre planted in northern climates, and it produces all year long and grows plants significantly faster.)

Light and Minerals

I do keep 1000 watts of LED grow lamps high above each pair of plant raft tanks. This helps during the short winter days and extends the length of day from 5am to 9pm every day of the year when the sun angle is low to the rafters. I do keep all fish tanks covered with polystyrene to reduce algae growth and prevent tilapia from jumping out of the tanks. They only need enough light (small hole in each poly cover) to see their food. The food of course is the only input into the system, unless you add mineral supplements, which I highly suggest you do with new systems. Iron, particularly, as well as zinc are rapidly utilized. There are several products– Flourish, Flourish Trace, and others– that are useful. I suggest you purchase a laboratory grade pH meter and calibrate it often. Purchase mineral test kits, ammonia, nitrate, and nitrite test kits, as well as test kits for iron, calcium hardness, total dissolved solids, and potassium. The better handle you have on your water quality, the faster you will be able to react to deficiencies in your system before they appear as yellow spots on your growing plants.

Air

Air is delivered by two very large redundant commercial air pumps. They pump air around the system in 1-inch PVC that is adapted down at the point of the airstone. All air delivery systems are located above the water to prevent siphoning. Only the stones are in the water. There are eight, large, silica airstones in each plant raft tank under the polystyrene to provide oxygen to the roots, four large stones in the gasification/degassification tanks, four stones in each of the fish tanks, and six stones each in each of the four glass tanks for a total of 92 BIG airstones in the system. Air is mission critical, so 24/7 power is a big thing.

Heat

The main heater for the system is an industrial 12 AMP 220 volt inline heater that senses water flow through it for safety. It has a digital thermostat and has never missed a beat. I do have a couple of smaller aquarium heaters in the glass refuge tanks for a little warmer conditions there, if necessary, and as backup for the inline system should it fail. (I also keep redundant pumps/heaters/thermostats and so forth on premises.)

Maintenance and Feeding

Maintaining the system is certainly a daily chore. Typically, it requires no more than an hour or so, depending on the day. Feeding small fish is a four time a day job. Larger fish require feeding twice or three times, if you want them to grow fast. You have to run some chemical tests and do some cleaning and crop work, but there is NO WEEDING AT ALL!!!Tomato plants need pinching, tending, tying up when blooms set, and so forth. Flowering plants need artificial bumble bees (a vibrating tooth brush will do) to pollinate. I find that big wall fans will do most of the work for me though, particularly with sweet peas. The clarifier tanks get about 10 gallons dumped per day each out the bottom drain valve, which purges all the fish waste out of the system and a couple of fish per clarifier disturb the tanks walls to help let material settle to the bottom. Occasionally, one of those fish gets the flush and ends up on the floor. If I don’t see it immediately, they turn into dried fish chips in the sun. Since I have roughly 400 smaller fish in the system, this is an acceptable, though undesired, occasional loss as are suicide jumpers. I pressure wash the floor, which is epoxied, to get the fish poop off of it. You can alternately collect the waste water and pour it on your fruit trees. It’s really good stuff for them. The glass tanks need surface algae removed to be able to see the fish occasionally, which is important for breeders. The plastic tanks hide the fish, so an underwater viewer (bucket with a clear plastic bottom) is needed to see the population inside. You need to feed the fish an appropriate-sized fish food pellet in amounts that balance the waste levels to what the plants will consume. What fish eat in the span of five minutes is appropriate. You can see from the amount of foliage my system supports, with multiple crops even, I feed over four ounces of pellets a day for the system. I have multiple sizes of fish, so multiple sizes of food is necessary. I am currently using five different sizes of feed. I keep the bagged feed sizes I’m not using in a freezer to extend their longevity.

Seeds

I am using heirloom seeds when I can and have had excellent results getting seeds to replant in the system. Using indeterminate tomatoes will eventually make me grow them horizontally along trellises using the areas above fish tanks for growing area. All the crops are healthy, happy, and disease free so far. Note to tobacco users/chewers/snuff users: Stay out of aqua/hydroponic operations. Dried tobacco has tobacco mosaic virus mixed in. Users shed viruses all of the time. This nasty virus will kill tomatoes, and the presence of it will necessitate the sterilization of the whole facility (kill fish, kill plants, et cetera) to eliminate it. Word for the wise, if you smoke don’t try this technology. Instead, quit. I keep a bug zapper (UV) running in one corner to keep any bugs at bay, and I use a mosquito net (double) over the intake vents of the fan system to keep out the “nasties” in the summer.

Cost

Your cost varies on the system you decide to start and the structure (if any) you decide to build/construct. I easily have 125,000 dollars into this project. Industrial projects start at 1.5 million dollars and go up from there. There are less expensive ways to do this, but few are more productive from the space/quantity of produce perspective. I’ve seen shoestring systems put up for hundreds of dollars using used tanks, but be sure that they are food quality and were never poisoned with solvents et cetera. Your ingenuity can fly with this. I hope you are good with PVC plumbing. There are over 500 pieces of PVC involved in my project. I lost count months ago. If you have an existing greenhouse, it is a good dovetail into your operation, as long as you can keep the system warm. My first salads were coming in at 10 grand a dish. They are getting way cheaper now after several a day. The payback time (as with most preps) will be down the road when fresh veggies are unavailable at any price.

EMP

A thinking observer will ask, what about EMP? It will shut down your system. Probably. I can instantly turn the system into a non-circulating hydroponic system, as Dr. Kratky describes in the link above. I’ve still got the pit greenhouse to start plants way earlier, and I’m generally better off than most if the EMP shuts down systems. I’ll have lots of smoked fish for a while too, as well as wrinkled hands after filleting hundred of Tilapia all at once.

To summarize, veggies are going to get expensive and some unobtainable. If you like it, you should grow it. There are many easy ways to provide for your family, ranging from standard gardening and canning to non-circulating hydroponic and even aquaponic systems. All systems are scalable to your space-budget considerations. The science is critical but not tough. The time to study is now as skills are not easily learned when the Shumer really hits the oscillating air movement device.

“In one century we went from teaching Latin and Greek in high school to offering remedial English in college.” – Joseph Sobran

Aquaponics is a practical skill to learn for prepping now, while the ability to obtain all the pieces and parts exists. The technology of aquaponics combines raising fish with gardening vegetables only in water. (There is no soil used at all). This usually takes a dedicated room that is water resistant, a reliable continuous (read redundant) source of electricity, food safe tanks of various sizes (any material from plastic to glass), and a good source of water. With the drought in California, which is the part of our nation that supplies a major proportion of the vegetables we find in our stores, reaching epic proportions and potentially hitting historic norms (California is a desert historically), it may be very important to be able to supply your family with vegetables. Based on my experience with my system, I think I can grow anything I can get to sprout. Sprouting various vegetables out of the soil is a challenge all by itself that I won’t discuss here. Water usage in Aquaponics is very low at around 3 percent of a regular garden operation. California should convert to all Aquaponic farms immediately.

Most set ups are small scale, though very large scale, industrial aquaponics businesses have sprung up across the country. For the purposes of this article, I will discuss family-sized operations. My little system is capable of raising 500 pounds of Tilapia (fish) per year as the harvested biomass equivalent of 4000 heads of lettuce a year. This is WAAAY more than my family of six can eat. We have fresh salads daily, fresh fish on demand (literally fresh fillets), tomatoes off the vine in January, peppers, eggplant, peas, cabbages, and spices all year round here in very snowy country. Seeds are available everywhere. Tilapia MAY be available locally from someone like me (I sell them to smaller guys), but ordering them on the web will mean a big airfare, unless you live near a Tilapia farm. (Don’t mix other species with your Tilapia. Do not add snails, gold fish (particularly), or anything else, please.)

My Aquaponics Greenhouse

My garden is established in a 40’X16’ underground greenhouse design, known as a pit greenhouse. The floor of the greenhouse is eight feet below grade and is done in poured concrete with drains every eight feet along the center of the floor for drainage. The walls are eight-inch, reinforced concrete, which is mostly insulated (as we live in a cool climate to -30 in the winter) by dirt which moderates both hot summer temps and cold winter temps. Essentially the structure is a basement with a greenhouse ceiling. Having two inches of polystyrene on the upper four feet of the outer wall moderates winter freezing considerably, also reducing condensation from the very humid environment within on the cooler surfaces. The green house slanted roof above is made of two layer Lexan™ specifically made for green house applications. We used redwood beams wrapped in mylar (reflective) for the roof span. Even with the two layer roof, condensation all through the cool months cause it to rain every day in the greenhouse. This necessitates using all plastic, aluminum, glass, stainless, weather-proof wood and other material for fixtures, cabinets, and tanks, as well as outdoor rated electrical equipment. Big exhaust fans during the warmer month(s) automatically start when the temperature hits the 80 degree mark and shut off at 70. In the summer we extend a 40 percent shade cloth over the structure to reduce heat gain and excessive sunlight on the plants. Even tomatoes will grow under 60 percent full sun. Growing tomatoes is the pinnacle of success with aquaponics, so they are something to shoot for about a year from starting your system. New systems will not successfully grow them.

Any aquaponics set up may be scaled to suit the size area you have available for the operation. There are many different kinds of aquaponics systems, and I will talk only about my set up. It took me a year from inception of the idea to get it all built and working to the first crop. Again, each building situation will be different. Warm climates versus cold climates obviously have different requirements for maintaining year round operation (keeping things warm but not too warm and so forth). Alternative energy sources are obviously quite applicable for this technology if you can guarantee 24/7 water circulation to your operation. Our heating bill for the whole severe winter this year was 250 dollars worth of propane. It never got below 65 degrees all winter. There are some operations that utilize hot water from nearby oil wells for heat during the winter. Others use solar water systems, while others use solar electricity. I have 4000 watts of solar panels, grid tie in, and propane generator redundant backup, plus the ability to plug in a small gasoline generator if I have to. Again, 24/7 power is a requirement for aquaponics. If you don’t have this ability, you need to consider non-circulating hydroponics. A researcher/PhD at the University of Hawaii called Kratky has a video that explains that technique in detail. Greenhouse design is outside the scope of this discussion.

If you have had aquarium fish before successfully, you should be able to master the skills necessary to raise Tilapia in an aquaponic setting. (My wife and I used to own and operate a pet shop.) Tilapia fillets are sold in grocery stores all over the country and are almost all farm raised in ponds from warm areas. Some states prohibit their presence due to their ability to rapidly populate warm waters. Water under 58 degrees will render Tilapia sterile and unable to breed, so northern states have no such limitation. Tilapia are mouth brooders, and females will protect eggs and fingerlings IN their mouth when danger appears. They are hard NOT to breed, and over-population is sometimes a problem.

The Cooperation of Fish and Plants

The object is, of course, for the fish food to be processed by the fish, the fish then poop, and the poop converts via bacteria eventually into nitrate, which the plants consider fertilizer. Tilapia and plants living together need compromised water conditions. Tilapia are prolific breeders, if fed well and kept in proper water conditions. For aquaponics purposes, your water should have a pH of 6.4-7.0 and never be any higher than 7.2 because plants start to starve (unable to take nutrition from the water). Plus higher pH’s tend to make what ammonia is present in the water (from fish respiration and food/fecal decay) to be more toxic coming out of solution over pH of 7.0. Water temperature is also a compromise. Tilapia do better at 80 to 85 degrees. They grow very fast at that temperature. Plants don’t like it over 75 degrees, so that is where my system is set.

The size of your system will determine how many fish and how many plants you can grow. My system has eight fish tanks, consisting of two 125-gallon breeder glass tanks, two 40-gallon refuge tanks, and four 110-gallons plastic tubs for feeding out/growing the fish. That’s a total of 770 gallons of fish elbow room. There are three 70-gallon plastic settling/filter tanks, called clarifiers, that remove any large floating debris/fecal matter/uneaten food from the fish tanks and two anaerobic mineralizing tanks (40 gallons each) that catch small particles and then let them slowly turn into trace minerals under low oxygen conditions. Water from the mineralizing tanks flows into a small heavily aerated tank that drives off any CO2 from the water and adds O2 to the system. From there, the water flows to the plant raft tanks. My total tank capacity is roughly 2000 gallons. You can keep as much as one pound of fish for every two gallon of water in the system, but that is a maximum. Your milage will vary. More population means VERY close monitoring of conditions. With that many fish/that much feeding, things could go bad very quickly. You have to be meticulous about your water quality.

The water actually is on sort of a race track as it circles about. In my system, two 1” pumps push water from the last plant tanks (lowest part of the system) up to the fish tanks (highest part of the system). From there, water just runs down hill to the clarifiers (first filter tanks), from the clarifiers to the mineralizers (second filter tanks), then to the degassing tanks, then back to the plant raft tanks. When I drain water from the system, an automatic float lets in reversed osmosis (RO) water, which prevents an increase of total dissolved solids into the system. This necessitated a 1000 gallon a day RO filter, which wasn’t free unfortunately. You have to add your own salts to the water for pH buffering (the tendency of the water to be stabile at a certain pH level because of hardness). This is better than having hard water in the system and increasing its hardness due to evaporation and replacement. The only way to deal with that is to do regular (weekly) partial water changes (read work). The RO does a lot of that for you, though it doesn’t reduce overall water use. It just makes it so you don’t have to change water as much manually, which results in the loss of trace minerals you work hard to accumulate for the plants.