Backyard Aquaponics
A place to discuss aquaponics

Im sure i have read it here before, but how does a plant in AP get its minerals, like a plant in dirt does?? is it in the fish waste, or is it in the worm castings??

Both.... but it's primarily the action of the worms breaking down the fish wastes that is responsible...

yep. Mostly from the fish food that gets broken down by the fish and then broken down by bacteria and worms.

Then there is some mineral content that could enter the system via the source water.
And from the media.
And then there are pH buffers that also provide supplemental calcium and sometimes magnesium or even potassium.
Finally some people find they need to supplement iron and occasionally trace elements and potassium. Trace elements and potassium are often supplemented by using seaweed extract or even sea water or salt in small quantities.

but if you use really high quality fish feed, some people find they don't need to supplement anything at all.

And pH has a definite influence on trace element uptake...

Yep, if you're taking minerals out in the form of fish and veggies and eating them, they have to get back into the system somehow..

thanks guys. im doing regular seasol/potassium/iron already

And as the system ages they tend to have more trace for the plants.