I was recently asked to write about hydroponics and aquaponics. I know enough about aquaponics to create a system, but do not have one. In the neverending list of projects, this one is a little lower on the list, but I definitely want to build one eventually.
Basically, Hydroponics systems involve a grow bed with flowing water. The water has an injection of minerals and food that is pretty much hands off, except the refilling of the mineral solution. The water is kept aerated by a bubbler. The plants are usually given a bed of rocks, gravel, peet moss, or similar material that will hold and trap the vitamins while providing a medium for the plants to cling to.
A form of Hydroponics is called Aquaponics. What is the difference though? Aquaponics no longer has the vitamin solution being added to it. The way we get the nutrients to the plants is through poop! There is another tank with fish in it. These fish eat the fish food that you feed them, crap out waste, which is great fertilizer for the plants. The fishy crap water is then pumped up to the grow bed. The grow bed fills up as the water is pumped. Once a certain level is reached, a syphon pipe, then creates a negative pressure that automatically dumps the water back down into the fish tank.
The plants and grow media, both help aerate the water for the fishies. Both products end up feeding off of the other. The idea of symbiosis is a permaculture principle, even though the system itself is not a permanent culture, that would continue without power or our interference.
So what are the main advantages and disadvantages?
The systems can be expensive, but if made in a DIY fashion with a 250gal IBC tote can be very inexpensive.
The fish in the system is freshwater fish. One of the primary fish used is tilapia, because it is a good edible fish. You can use Jade or Silver Perch, Eel-tailed or Tanandus Catfish, Koi, or Goldfish. Temperate climate systems have the ability to use Bluegill or Catfish in their systems, and they don’t have to worry a lot about the water temperature.
Plants and Media:
Leafy plants tend to work well in the system. Plants like tomatoes, lettuce, cabbage, okra, cantaloupe, and bell peppers are pretty hardy in the system. Beans, peas, strawberries and melons do well also. Many people say that radishes, sweet potatoes, and onions do well, but I think I would stray away from attempting “root veggies.”
There are several types of media used in different systems, proof of how versatile they really are:
Bacteria is needed in the system because the fish create ammonia as a waste product. That ammonia can be absorbed by the plants in small quantities, but not enough. Add in Nitrosomonas that turn ammonia to nitrites and Nitrobacter that turns nitrites into nitrates, then you have a very absorbable nutrient for the plants. Worms can be used for the solid waste to be liquefied. Biofilters are used to encourage the growth of the bacterias. PH is a little bit erratic until the bacteria systems are in place, so some base chemicals may need to be added for startup.
Enter the challenge for: