Here is a comparison of two small-scale growing systems that I have in my kitchen. One is an aquaponics system with a 10-gallon tank of tropical fish. The plants are grown in 5" net pots filled with hydroton. The other is a non-circulating hydroponics system where the nutrients are in the water below the foam top that holds the plants. The plants are grown in 2" net pots filled with coconut coir. I planted both these systems one week ago. Actually, I planted the hydroponics plants 8 days ago and the aquaponics plants a day later. I cannot believe the difference in growth can be attributed to one additional day in their little plastic prisons with their roots in cheap potting mix.
Here is a closer look at the aquaponics system:
I use a Finnex PX-360 canister filter to pump water from the fish tank to the planter. I took out the charcoal filter that comes with the PX-360. Instead, I use polyester filter media, which I change monthly. The water comes down from the planter back into the tank using a Botanicare ebb and flow fitting kit. Right now, both of the extensions for the kit are being used on the hydroponics system to keep the water level high. So, at this moment, the aquaponics system is not performing flush and fill. There is about a quarter inch of water just freely flowing across the bottom of the planter. I should receive the new ebb and flow kit (with more extensions) this week from Amazon.com. I made a bell siphon by cutting notches in the top of an old Tupperware sugar container, adding a piece of aquarium tubing for a snorkel (secured with a small piece of string), and setting it upside down over the ebb and flow drain. I have used a piece of lead crystal to hold it down. Don't worry, the lead does not contact the water.
Here are the two systems side by side: the aquaponics is on the left under the fluorescent grow light, and the hydroponics on on the right under the sodium grow light.
Let's have a look--the roots are coming along nicely.
Let's take a closer look at the plants. The cilantro plants on the left were larger plants to begin with, and they are growing at a normal rate. The arugula on the right were from a veggie pack; they are not growing as fast as I would expect them to. Two other veggie packs, kale and mixed greens, were split between the two systems. Let's compare them.
Maybe the sodium light is too harsh over the reflective surface? So, I switched the lights around. The fluorescent light won't emit heat, which might be drying out the hydroponics foliage. I also moved the kale plants closer to the light source on the hydroponics side.
In case you missed the first post in this series, you can find it here on my blog. I posted it under farming on March 8.
Check back in a week to see if the hydroponics plants catch up.