Now that our patio aquaponics system is well into cycling after the introduction of tilapia, we are ready to plant our first seeds in the grow bed. As you may recall, cycling is the process of building beneficial bacteria in the system in order to efficiently convert fish waste into nitrates and nitrites, which our plants will eventually use as fertilizer. It’s time to add those plants — if not, nitrate levels could reach a toxic level which could kill the fish.
Heirloom organic seeds
We’re exclusively using heirloom organic seeds so we purchased our first batch of romaine lettuce from Annie’s Heirloom Seeds. Annie’s ships their seeds in standard USPS and are packaged in branded packets. We were a little disappointed in the number of seeds for the money you pay ($2-3 per packet, with $7 shipping charge) so we’ll explore other sources to see if there is a better value for farming on a small scale.
We understand these seeds are better quality than what you’d purchase at the local big box store, but I think you still need to match volume since those seeds are only $1-2. Plus, we’re starting to see a lot of branded seeds options on the market (think Martha Stewart), that are not heirloom, nor GMO-free but get into the $2-3 price point as well — and those packets are loaded.
Use of rock wool
Some aquaponic farmers throw seed right into the hydroton pebbles but we prefer to set them in rock wool, then place these cubes in hydroton. Although we’d space these wider in a large outdoor system, we’re unsure of how much we could squeeze in our system. For this planting, we’ll space them about three inches apart.
As they grow under artificial light, we could easily lift the rock wool out of the hydroton to re-space. This is the primary reason why I choose to set in rock wool first. We’ll do our best to space as tightly as possible without sacrificing plant quality by stunting growth.
Seeds germinated after two-three days and are growing vigorously. Although we have not hit the recommended 30 days for a tank to completely cycle, we suspect there is enough fertilizer in the system judging from the vigorous growth of the seedlings. I’d consider our first planting in the patio aquaponic system a success.
We plan on planting arugula, bok choy, escarole, water cress, mustard and basil in the future.