Most people interested in commercial aquaponics invariably start looking at potential yields of different crops and then, after a thorough literature search, will discover that there is very little available in terms of potential yields of larger crops. Stuff like basil, lettuce, tomatoes and cucumbers etc. seem to be written about the most.
With the advent of what I consider to be the most likely design for my own use in a commercial environment, namely gravel beds and rafts in conjunction with some vertical structures, came a search for the “ideal” commercial gravel species. Tomatoes and cucumbers were obvious choices to explore, but there are many producers around thus competition for market will be tough. Then I stuck a passion fruit vine in my home unit. In the first season, it grew from a foot-tall sapling to bearing over 130 fruit on my side of the wall (my neighbour also gets some!). This year, I thought the yield was going to be poor as I have replaced the 37 large tilapia with about 27 small koi. There are some signs of nutrient stress, but the vine is determined to outdo last season’s output. I have counted well over 130 fruit on my side of the wall just from the spring flush. At around R25 for 4 – 5 of these fruit at our local stores, I’m looking at a yield of R812 (market value) odd from just one plant and in one season. It slowed down in winter in the open system, but all the fruit formed last year matured.
In terms of management, it is in its own gravel bed, and in more than a year in the unit has not clogged the inflows or the bell siphon. As said, I can see signs of nutrient stress, but the vine is hardy and determined to fruit like mad. I would love to have a controlled environment with 50 or so of these vines going, together with the traditional leafy greens and cucumbers……………