- Created on Thursday, 13 March 2014 00:51
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By CATHY McCABE
“It completely reduces the amount of water. It just recirculates everything.”
Three second-year Greenhouse Technician Co-op students have built a hybrid aquaponics and vermiponics system for their Greenhouse Crops II class.
Josh Petzold, one of the students working on the project, says vermiponics is using vermiculture, which is the raising of worms, to assist in the growing of plants. He says, “Aquaponics is hydroponic growing with aquaculture; aquaculture consists of culturing fish or raising fish.”
They are using Red Nile Tilapia fish in their system.
The system is hydroponic meaning the plants are grown in water instead of soil. The water is pumped from the fish tank to the plants and then back to the fish tank.
Brian Ellis says one benefit of this system is they do not have to switch out the water. He explains that the only place where the water becomes dirty is in the fish tank and once it is pumped up to the plants, it is cleaned.
“That’s the point of the plants feeding on the water; they pull out all of nutrients to bring the electrical conductivity back down. The gravel collects all of the solid organic matter, so it is trapped there and the worms eat it, so anything that is sent back is just fresh water. That’s my favourite part about it; it completely reduces the amount of water. It just recirculates everything.”
Petzold says one of his favourite things about the system is how little water it takes. He says it uses about five gallons a week, while the hydroponic tomato crop the class is growing in the greenhouse uses about 100 gallons a week.
Jun Liang says, “It’s a totally enclosed watering system, so all of the water being used is through evaporation or by the plants. None of it is wasted.”
She says the plants they grow are 100 per cent organic. They do not add chemicals. “Sometimes we need to adjust the pH, but we just use vinegar.”
Ellis says the vinegar is supplemented with crushed egg shells. “We put them in the vinegar and it helps with calcium. One of the major problems when you put fish in it is the fish are actively growing and they pull out a lot of calcium for their bones.”
They have planted thyme, chives, purple sage, lemon sage and rosemary in their system.
Petzold says you can grow almost anything with this system.
“You could grow peppers, tomatoes. You could grow flowers. The biggest thing is making sure whatever plant you are growing will be tolerant to the amount of water that you are putting through,” he says. “They are getting a lot more exposure to water than a soil system would have.”
Petzold says their system has not matured yet.
“It’s brand new, but in a month or so when the bacterial cultures get a better foothold in the growing medium it will be much more self-sustaining. It will grow plants bigger and more quickly than a soil medium will.”
The group says they plan to use this technology at home in the future. Liang says, “You can do it at home by yourself; it is not very difficult.”
Ellis adds that their system is based on “what happens in nature. When you see lakes or ponds, this is what is going on. We just found a way to replicate it.”
Petzold says when making this system, “You’re basically recreating an entire ecosystem. We could take worms out and use them to feed the fish and never have to buy fish food. The fish are constantly feeding the plants; you never have to buy fertilizers.”