Backyard Aquaponics
A place to discuss aquaponics

Correct me if I'm wrong(please) nitrogen, phosphorus, potassium, are the "big three" calcium, magnesium, sulfur "lesser three" and iron, manganese, zinc, boron, copper, and molybdenum the micro nutrients needed for plant growth. Obviously the nitrogen is taken care of with the nitrogen cycle. I live in Botswana where it will be difficult to buy things like Seasol. Does anyone know of some natural ways of getting these other essential nutrients into the system. I have lots of daily multi-vitamins which have many of these nutrients in them. Is this a form that would break down enough for the plants to up take them. Also I've read some posts about grinding up sea weed and using that... in our local dam we have lots of under water vegetation... could this be a possibility? I don't think it would hurt the fish because this is where i will be getting the fish from.

thanks

Jason

What are you planning to feed your fish... many fish feeds, whether pellet or other things... will contain the trace elements anyway...

I plan on feeding any high protein source I can find. mainly duckweed, soldier fly larva, various insects depending on time of the year, and believe it or not I found a place that sells pellets. I want to stay away from as much buying as possible but know depending on the density of the fish that I will probably need some store bought pellets.

Have a look at growing the Moringa plant....

The apparent lack of trace elements was (still is) my concern as well. My system is only very young but the plant growth has recently started to improve greatly. My only input is the high protein fish pellets I source from the the BYAP store.

I wanted to use what the store was using so as not to confuse any plant growth differences between my system and what I've seen at their shop, which is pretty good (understatement). Apparently Perth systems can show iron deficiencies now and again so some chelated (soluable) iron is added.

The Seasol stuff that folks talk about here is lower in nearly all elements than most other liquid fertilisers and significantly lower in N than P and K. So it's a tonic when compared with other things on the market (eg: Thrive) and great fit to AP because of its lower N ratio. If I didn't have Seasol available and I wanted to boost plant growth I'd look for something that was lower N ratio to other elements and over dilute before adding to my system. Gently gently.

Two considerations:
1. If you only grow one species of plant you may be able to identify a particular deficiency and simply target that rather than going for a 'multi-vitamin'.
2. If you just want rip-roaring plant growth why mess around with fish? Hydroponics is the proven technology.

The message I seem to be getting and what seems to be bearing out in my system is, give your system a go without additives and see what it can do. You may be very pleasantly surprised.

I'm in it for the fish first. Any edible produce and reduced water waste is a huge bonus.

Aquaponics systems do "mature" with age Aquapete... as evident in those at the BYAP shop...

Any initial "deficiencies are usually pH related, and again... with the natural pH drift as the system matures.... usually become neglible...


We don't recommend Seasol as a fertiliser, or for nitrogen content... as you say the nitrogen component is low....

And nitrogen is generally the very last problem in aquaponic systems... which if it were the case... would be exhibiting other problems anyway... and are easily rectified by the addition of more fish/feed... usually not a problem with "current" stocking rates...

Indeed, we recommend Seasol... as a tonic... and a trace element top up...


Absolutely... but any deficiency is usually either only in the early stages of an AP system... or pH related.... additives are a last resort... address the fundamental problem...


Bullocks... my AP system outperforms hydro... IMO... at far less cost (nutrients), less water usage, and less time/management...


Now you're talking... patience... your system will mature... and impress you... IMo... the fish are the bonus...

More great advice Rupe. Do you ever sleep???

Rupe,

Seems we agree on most points, which is good.

However, until I see a commercial Aquaponics setup with better rip-roaring plant growth (of virtually any species of plant) than is plainly visible in any well run commercial Hydroponics setup, I stand by my statement. I'd love for AP to be the future of grocery and florist supply... one day. Till then, for me, Hydro is the proven technology for plants (only).

Still, I like mucking around with fish more than I like mucking around with nutrient solution or a shovel. Way more enjoyable.

Respectfully,
Pete

I would not use vitamins to help plants as they do not typically contain the needed minerals. One may be able to find pebbles (for growbed) or bones or rock dust (or soil) that will provide the needed minerals.

Ahhh Pete... now commercial scale is another matter entirely than backyard production...

And yes I agree... exisiting commercial aquaponics operations seem limited to herbs, asiain greens and lettuce....

But then again... so are most commercial hydroponic operations....

Given all other parameters (light, temperature, humidity, pH, etc) are the same the limiting factor for plant growth in AP is the nutrient level (the topic of this thread). Which is why commercial setups focus on lettuces and herbs as they only require an EC (electro-conductivity) of around 1.6 for optimum growth. And is why tonics such as Seasol are added.

My AP has is currently around 1.5 EC and pH around 6.0 and is giving great growth to my mature chives and sage, young tomato and lettuce. The oregano is finally growing too. Only input is BYAP fish food and Perth water. Simple.

I keep my Hydro system around 1.8 to 2.6 EC and pH around 6.0 as well. We've been overrun with cucumbers for the last month and the passionfruit is taking over the place. The capsicum is twice as high and has twice as much fruit as the soil based plants. And the strawberry plant is sprouting runners all over the place. Inputs to this system are water top up and pH adjust daily, new solution every two weeks, top-up of solution when EC gets low. Slightly complex.

The different technologies are different 'animals' with different, albeit similar, inputs and outputs. I guess people get into AP or Hydro for their own reasons but if you're only interested in plants I'd have to ask, why bother with the fish? And to answer my own question, I'm interested in the fish, my kids and I love watching them feed and grow and the edible plants are a great bonus.

Maybe others are into AP for the plants and are happy to 'bother' with the fish. Would love to hear reasons folks got into AP. New thread maybe? Or has that already been hashed out?

What about you missionaryman?

Can never happen.

Why? Fish will not survive at the nutrient saturated levels that hyrdroponics can achieve.

Yes and no.... Seasol is added as a trace element supplement... not as a "nitrogen" source...

In fact Seasol is low in all three NPK measures...

We need to be careful when we talk "nutrients"....

In hydro... nutrients are a mixture of water soluble trace element compounds, essentially chemical "salts", typically "chorides, sulphates etc"... which readily disassociate into "ionic" form... which is what EC reads...

And a source of nitrogen, sometimes as a "nitrate" compound, sometimes as urea... as is typically the case in 2 part nutrient mixes...

In the latter case the urea breaksdown into an ammonia based compound, which just as in AP is then converted to "nitrates"...

I would contend that in fact, in both hydro, aquaponics, or even in soil.... it's principally the "nitrate" provision that drives plant growth.... the provision, while necessary, of trace elements are somewhat secondary.... and more relevant to plant species, particularly flowering, fruiting, seeding plants...

Most lettuce, asian greens etc, really only require sufficient "nitrates" and iron... hence their suggested low EC reading...

Along with fast growth turn-around and market availability, that's the reason many hydro operations concentrate on such plant species.... fast turn-around, almost fool-proof, low nutrient cost, low management...

And most hydro operations are dedicated to only one or a few plant species... unless very large operations...


No arguement from me regarding preferred pH range in hydro or AP... it's simply a proven fact that trace element uptake occurs best within the suggested pH range...

But as you point out... hydro requires nutrient mix & water replacement... seperate plant growth areas... and regular maintenance and monitoring...


Again, yes and no Pete.... the inputs are different, in form, and particularly in terms of management and time... in hydro you need to mix chemical nutrients, (now becoming very expensive), and periodically replace them...

In aquaponics... we just feed our fish... and perhaps, very occasionally, add a bit of chelated iron and/or seasol...

In hydroponics... we tend to grow a single species in a "grow area"...

In AP... I grow ALL my vegetables in a single growth area (growbed)... with minimal water top-ups... minimal (to none) monitoring and maintenance....

With quick growth, good yield and virtually no fuss.... and without the need for "spent " nutrient disposale...

And I get the bonus of fish added to my diet...

On a commercial scale, hydro operations are quite capital intensive to setup, maintain and manage... but have an accepted and almost gauranteed market...

"Commercial AP" on the other hand... while perhaps similar in capital investment to startup... has much lower running costs, management and on-going costs... but has a somewhat undefined market...

For backyard food production... unless you're prepared to grow your own seedlings and run mixed batch plants in hydro... aquaponics is just a "no-brainer" in terms of cost, simplicity and management...

Commercially... IMO... there is a very strong case for considering aquaponics, particularly the UVI raft methodology...

P.S... I think I can claim some hydroponic knowledge, even at a copmmercial scale... and from my experience... EC, TDS etc hydro readings... don't mean diddle-squat in relation to aquaponics... simply because they measure "variables" that just either aren't present in AP, or are in a different form...

I haven't used my Bluelab in a couple of years... other than to take a reading every now and then whenever this type of "question" is raised...

In all that time... I've never been able to compare the EC readings in AP systems with anything I've seen or experienced in hydro... but my plants are htriving and growing .... just as quickly..

My understanding exactly. Although I have read that some folks are using the waste water from a more traditional aquaculture setup as the input for an attached hydro setup, thus they don't need to add as much nutrient to the hydro. That approach seems to me to have better commercial potential but also seems fiddly in that the fish waste water would need to be monitored closely to see how much of each element would need to be added before delivering to the plants. Also at what stage, if at all, could the hydro water be recycled back to the fish, stripped of nutrient. Still, it's not what everyone else is doing in their backyard anyway, but an interesting aside for those thinking big.


Thanks for all the extra clarification Rupe.

I must confess I'm very pleased with the simplicity and growth being achieved in my backyard system. More than satisfactory.
Just put in a strawberry runner today to add to the existing variety of plants being grown. Hope it takes.

Joel has photos somewhere of a large hydro setup in Perth where the bloke has fish for mosquito controll [you know the one all made out of cliplock on about 2 or 3 acres]
Also both Jim and I have seen a hydro system at kinglake that had a silver perch in the hydro tank
I have photos somewhere of both systems