Backyard Aquaponics
A place to discuss aquaponics

I'm relatively new to aquaponics, actually still haven't had a successful grow. My plants tend to get stunted and then develop black spots, then wilt and die. Kind of depressing, but I'm still hanging in there, trying to figure it out.

My latest attempt was to start some basil in potting soil, then I transplanted a cutting of the plant to my aquaponics system. It start to have some new growth, so I was hopeful. But then the leaves started curling up and the black spots have started to appear. They are primarily on the new growth leaves. I'm assuming I just have some nutrient deficiency in the system, so I'm trying to identify it so I can possibly correct it.

Anyway, here are pictures:



My best guess is calcium. Anyone else have any thoughts? Is there a supplement I can add to help? I've already supplemented with maxicrop.

Some other information that might be useful:
pH: 6.5
Ammonia: 0
Nitrite: 0
Nitrate: 80+
Temp: 65°F
It is an indoor system in a west facing window, with a CFL providing supplemental light.
Fishless cycling (pretty much ready for fish, but want at least one healthy plant before getting fish)
Its a small system, 10 gallon fish tank, 8 gallon grow bed
Flood (15 min) and drain (45 min)
Air pump rated for 10 gallon tank

Welcome to the forum .

Basil is pretty sensitive to temperature, what's the water temp - that may be making it more susceptable to diseases. I don't think it's a nutrient deficiency.

+1 for Scotty. 65F is too cold to grow basil which is a warm temp plant. In addition, it needs full sun - your plant looks pretty leggy so I suspect it's also not getting enough light. Cool temps + not enough light leads to disease issues very quickly as Scotty mentioned. Your pH is right on though so try growing cooler weather plants - most leafy greens would grow great and most can grow under lower light conditions (lettuce, bok choy, etc.)

Water temp fluctuates a bit, but averages in the low 60's right now because of the cooling weather.

I agree about the legginess too. I need to figure out a more permanent solution for light, as my west facing window just doesn't seem to be getting enough light for much of anything, and my supplemental light is just in a desk lamp right now.

On the positive side, I do have a few lettuce seedlings popping up now, so we'll see how they do. Historically they've done pretty poorly for me, but we'll see shortly I guess.

Florescent bulbs work well for leafy greens but they have to be very close - no more than 4-6" away.

If you can't lower the bulbs or raise the plants, changing the bulb/s might be enough if these aren't new.