Soil based gardening has become dependent upon outside resources but Aquaponics is even more reliant. Some of those resources are affordable only because fossil fuels are still available. If those resources were not available how would you feed your fish? How would you supply nutrients such as iron, calcium, potassium, phosphorous and magnesium.
Aquaponics has good intentions, but it is not a sustainable agricultural method. I currently do not have all the answers, but I'm working on it. Here are some options and food for thought
I'll start by defining the problems. Fish food is made from grains and wild caught fish comprised mostly of fish with little commercial value, and processing waste. But the fishing industry is not sustainable, and much of the grain used to produce fish food is GMO; raised using large amounts of fossil fuels for fertilizer and machinery in order to produce a profit while neglecting the environment. For more about the analysis of fish food read http://www.oscarfish.com/fish-food-ingredients.html.
The result is that similar to feeding cattle enormous amounts of gain are used to produce a small amount of meat.
But we don't need to feed our fish commercially produced fish food.
David Epstein at Bioponica has been feeding his fish only vegetable matter. This is a great way to avoid dependance upon fish food.
Live food such as Black Soldier Fly larvae, fly maggots, worms, and other insects are also good sources of protein.
But do we even need fish? If you are like me an only eat fish a few times per year, maybe you will consider bioponics which replaces fish and fish food with humonia. Bioponics is hydroponics using readily available urine rather than fertilizers made with fossil fuels.
Humonia (aged urine) is a strong source of nitrogen and potassium plus it provides many other trace minerals. I have been growing with nothing but humonia, epsom salts and Fe-DTPA for quite a while, and I like the freedom it allows. Humonia will always be available, but iron and magnesium are still missing and a bit more difficult to make at home.
I personally have no problem using humonia for a nutrient source in a bioponic garden. Human urine shouldn't contain pathogens or bacteria if you are healthy. Aged urine turns to ammonia. But I get that some people would prefer not to collect their urine, or use it anywhere near a vegetable garden. So I have been exploring various avenues to find a source of nutrients.
What if you could grow vegetables without any animal input including humonia. Similar to David Epstein's plant matter for fish food; bags of plant matter can provide nearly everything a garden will need. For example coffee grounds can provide the following.
- Nitrogen: 2.28 percent
Phosphorus: 0.06 percent
Potassium: 0.6 percent
A little more research turned up these sources of nutrients:
Nettles, comfrey, yellow dock, burdock, horsetail and chickweed - Potassium
Cornmeal - phosphorus and nitrogen
Molasses – [ acts as a chelate ] [Calcium,Magnesium,Potassium,Iron]
Banana - potassium
Coffee Grounds - phosphorus, potassium, magnesium, copper, sodium and chloride
Egg Shells - 93% calcium carbonate
Seaweed – trace elements
Manure – nitrogen
Grass Clippings – nitrogen
Humonia – nitrogen, phosphorous and potassium
Wood Ash - calcium and potassium
Epsom Salts - magnesium and sulfur
Fish-Emulsion - nitrogen, potassium, phosphorous, and amino acids
- • Organic Carbon 20.43 – 30.31 %
- • Nitrogen 1.80 – 2.05 %
- • Phosphorus 1.32 – 1.93 %
- • Potassium 1.28 – 1.50 %
- • Carbon : Nitrogen 14-15 : 1 %
- • Calcium 3.0 – 4.5 %
- • Magnesium 0.4 – 0.7 %
- • Sodium 0.02 – 0.30 %
- • Sulphur Traces to 0.40 %
- • Iron 0.3 – 0.7 %
- • Zinc 0.028 – 0.036 %
- • Manganese Traces to 0.40 %
- • Copper 0.0027 – 0.0123 %
- • Boron 0.0034 – 0.0075 %
- • Aluminium Traces to 0.071 %
- • Cobalt, Molybdenum Present in available form
|Grass clippings - Over 3 days the Ammonia increases significantly Plenty of Phosphate too|
The iron in vermicompost and planting nitrifying legumes are the only sources I've found. Tests will have to be done. I have yet to grow a garden this way but it appears a lot will be learned when I do. Perhaps you too will set up an experimental Weedsponic Garden and let me know your results.