Backyard Aquaponics
A place to discuss aquaponics

This is Charlie, a Peace Corps Volunteer living in the Philippines. I've been working with my city agriculture office to start an aquaponics pilot project, just a small-scale flood and drain system utilizing an existing tilapia hatchery tank (that has basically been abandoned). My co-workers are motivated and awesome people and we've built most of structural components. We added fish yesterday.

Basic specs: 4,000L Fish Tank, 6 x 100L grow beds (half barrels), 1/4 HP Submersible Pump (way stronger than what I need, but I digress), and 25 x 4-inch tilapia.

We're starting out with just lettuce, petchay, and swamp cabbage.

Now this is where I feel really really stupid.....I've been reading up on aquaponics for a really long time, but I'm more of a fish guy than a plant guy. In fact, when it comes to plants I know only the very basics. But for some reason I was under the impression that an aquaponic system did not need additional supplements for plants (like iron, potassium, calcium, all that good stuff)....

I know that may sound naive, but i have read quite a few AP guides and they rarely mentioned this, and in some cases even touted the greatness of AP simply BECAUSE they don't need additional fertilizers/supplements. But now I'm starting to read about how lots of people are having nutrient deficiency problems and I'm getting nervous.

I've been browsing these forums for a while, but they are kind of overwhelming to a plant novice like me. I really LOVE aquaponics and am having a blast learning more about it (as are my co-workers), but plants intimidate me, haha.

If anyone has any basic advice or can post a plant guide or something, I would be greatly appreciative! Sorry if this has been discussed to death elsewhere, but I could not find a basic primer on the subject.

Thanks in advance!!!

Charlie

Hey Charlie... Whether you need to add supplements to a system really depends on the fish feed you use, as feed is the only real input of nutrient into the system. The feed I have used i the past wasn't the cheapest, but it had a very high fish meal content and contained almost all the micro and macro nutrients, so we rarely found any need to supplement anything. Some of our systems ran well for many years with no additions other than the feed.

Other feeds contain different ingredients and some are fairly lacking in micro nutrients.. We tried one feed that was really cheap for a few months but our plants showed some major deficiencies, swap back to the better feed and the plant deficiencies went away.

I think the best bet is to buy a better quality local feed and see how you go.. If you see plant deficiencies, then you may have to supplement, seaweed extract is the standard simple on to use as it has most micro-nutrients in it

Welcome Charlie (cool name)

You will probably get a bunch of different answers and points of view so here is my experience..

In all my systems in the past I have only ever added two things. One is chelated iron, as it is not usually available through commercial feeds. Second one is Seasol or Maxicrop (seaweed extract), for the addition of trace elements like potassium.

I rarely experienced any deficiencies in my systems and everything grew exceptionally well. But, there are others that experience deficiencies so they adjust parameters accordingly. pH is one to monitor as it will provide the gateway to nutrients available.

What they both said. Chelated iron and Seasol or Maxicrop are the most commonly used. Iron and Potassium are probably the most common deficiencies we see around here. Check the bottle if you get maxicrop to make sure you're getting one that has some potassium.

Wow, thanks a lot guys! This is really helpful. I know that my Ag office makes their own seaweed extract solution (fermented I think?) so I can get that if I need it. And I'll just have to search around to see what else is available. Hopefully my plants will grow well without too many supplements, but we'll see.

Once again, thanks a lot!!!

..
and also a welcome from me..

What I have started doing is a little different

First there is the whole AP system.. built as I saw it , not as to any plan

Then I have worm farms, processing all household waste and all the clippings from the AP gardens..
I have found what seems to be great success, in taking a tall and skinny tank...
Add the worm juice to it... add the finished worm castings... add some AP water and an air stone, and allow it to go through a mineralisation process..

After a couple of weeks, the settled result, is the most magic looking liquid that just must be the Bees-Knees of plant nutrition.. I try to ensure we get as many banana skins in there...

How I wish I had a machine to see the spread of actual nutrients..
..
.