One of the main design considerations that I struggled with when thinking about my aquaponic garden was what kind of light to use for my plants. I knew that if I was serious about growing plants then I would need serious light, but serious light can have serious costs both to purchase and to operate.
Some of the options currently on the market are LED, induction, metal halide, high pressure sodium and fluorescent. All have advantages and disadvantages, and everyone will weigh them differently depending on circumstances. A primary consideration for me was purchase cost, as I am definitely suffering from aquaponic shopping fatigue. Also, I am planning to move the garden to an outdoor bioshelter in the next year, so I can’t amortize the cost over many years. That ruled out LED and induction, even though they both have very high “cool” factors, literally and figuratively. The standard grow op lights, the metal halide and high pressure sodium, are moderately expensive and run hot, so typically require some kind of cooling in addition to the light. They are pretty much the standard, though, having been used for years to grow countless pot plants.
I decided to go with fluorescent for a few reasons. I am planning to grow mostly greens and herbs, rather than fruiting or flowering plants. This means my lighting requirements are not quite as high as if I was trying to get my pot plants to flower, or produce cucumbers or ripe tomatoes. I also already own four standard tube-style fixtures, with bulbs that were used for only a few weeks last year. I found two 125 Watt compact fluorescent bulb fixtures with bulbs included for $70 each on Amazon and bought them without a clear plan of how I would configure them. Initially, I hung one over each grow bed, but it was clear that the ends of each bed were simply not receiving the light they should. So today Luc and I built a diy fixture to hold all four of the strip lights, with 8 32 Watt T8 bulbs in total, to light one of the beds, while both of the compact fluorescent fixtures now hang over the other bed. The instructions for those fixtures say that the light should be from 1 – 3 ft above the plants, which seems a little vague, especially since tube lights are supposed to be just a few inches above the plants. All of the fixtures are height adjustable, so I will experiment to see what works best. Both beds are now receiving around 250 Watts of fluorescent light, which I believe is probably minimally adequate for 8 square feet.
I don’t have much experience growing plants indoors, other than seed starting and microgreens, neither of which are particularly demanding for light because I either kick them outside, in the case of the starts, or eat them before they complain too much. I am curious to see how these longer lived plants will make out.