Backyard Aquaponics
A place to discuss aquaponics

Hello everyone! I've got an indoor aquaponics grow going for a few different varieties of lettuce. I week or so ago I noticed these white spots showing up with brown rings around them. They have taken over a few of my plants and I have no idea what it is or how to get rid of it. Any advice would be greatly appreciated!

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It looks like Septoria leaf spot to me.

Septoria does cause spots similar to this but I'm pretty sure this is a severe nutrient deficiency, I'm just not sure which it is, it may be a combination . Notice the way that the older leaves don't appear to have the problem as bad as the new leaves. What level is your pH at, maybe it dropped to the point where the plant isn't able to get some of the nutrients it needs. Are you adding supplements to your system? Some of the nutrients compete for uptake into the plant - if you're over doing one it will affect another.

Let us know what you get for the water parameters (temp, pH, Ammonia, Nitrite, Nitrate) and don't try to adjust the pH without taking into consideration that a rapid change could hurt the fish. If your pH got really low the bio-filter bacteria could have shut down you may have some ammonia, toxicity is affected by pH and temp so we need to know what's going on

Good eye Scotty. I think the older leaves would be worse with Sep. You have a very good knowledge of plant pathogens. What's your background?

Thanks Chris. Mostly practice, practice, practice - I have a science background which included the usual courses along with a little bit of plant pathology and lots of different types of microbiology (most of it long forgotten).

Nothing like the farmer's shadow.

Can't put myself in the same league as those guys Chris but diagnostics is one thing I'm pretty good at.