Comparing Aquaponics to hydroponics

[gavinl]

G'day all:)

This is not meant to cause a flaming war, but rather I'm just interested in whether hydroponics is more or less advantageous than aquaponics, if someone is mainly concerned with vegies and not really interested in growing fish. I have trialled aquaponic flood and drain, hydroponics NFT and hydroponic flood and drain systems and am very interested to hear what others feel are the benefits and/or disadvantages of each growing technique. I listed a few things below which is not exhaustive, but might be considered as a start for comparison:

Waste:
I can see the beauty of using a waste product as a nutrient source in aquaponics. I was wondering however, if (old) hydroponic nutrient can be used to water certain plants, and therefore become a liquid fertiliser rather than a waste product?

Setup:
I think most hydroponic systems could be setup and closed down very quickly, whereas aquaponic systems need time to cycle - less important if transferring grow media or water. This might be important for people who rent and move a fair bit.

Plant varieties:
If the same flood and drain system was used (ie. tank, growbed, grow media, pump and timer), would there be much difference in the variety of plants grown? In hydroponics, one disadvantage would seem to be that plants would have to be grown which need the same nutrient range ie. vine vegies together (2.2 cf) and leafy vegies ( 1-1.5cf) together. Aquaponics however, would seem able to grow different vegies with different nutrient needs.

Vegie Health:
Hydroponics would seem to depend on the nutrients bought and the correct levels of micro and macro nutrients. Aquaponics would seem dependant upon the fishfeed and added nutrients used (ie rock dust).

Environmental concerns:
Disposal of nutrients is a major factor for hydroponics and a major advantage for aquaponics. On a small scale "used nutrients or waste water" might be used advantageously as a liquid fertiliser in hydro systems.

Fishfeed (good ones) use fishmeal, which is predominantly sourced from fish around Chile. Not sure where the nutrients for hydro systems come.

Cost:
There are different qualities of both fishfood and nutrients. From some research I've done, it would seem that good commercial nutrients would seem available for around $40 for 20L of A and B - enough for a 72 hole NFT system and two 250L small growbeds (offered on Gary and Murray's site) for a year. Good Fishfood (fishmeal LAP free) would seem more expensive - but others might want to comment on this. Also, fishfood feeds plants and fish.

[Murray]

Hi Gavin,
Short answer, I believe there is a place for both hydro and aqua. Aquaponics is not the answer to everything.
It really depends on what you individually want to produce in the end.
Personally,I love the fish.
If it wasn't for the fish I would possibly be doing hydro.
I had a chuckle over your comment that renters can move hydro setups quickly......loads of those who grow the wacky tabaccy move sites quickly. You can only imagine trying to haul a 2000 ltr fish tank down the road with the constabulary in hot pursuit.

[fishfood]

Most dont move there wacky tobaccy stuff they chuck it in the tip for ME:D

[Martin A1]

You are a legend FF!
I've said it before and I'll say it again... I love your work!

[fishfood]

Todays pickup bioballs for my bio filter

[Murray]

FF, I wished I lived in your shire. At our local tip there are heavy fines for taking anything at all. I have asked the tip guy for stuff and you would think I had asked him for a lend of his wife ......... Very un-cooperative . They will sell it to you though. Another example of the increasing greed of local authorities.

[Hamish]

FF - would be interested to see the list of all the things you have managed to find at the tip. Perhaps a new thread that you can add to each time you find something so we can all see how wonderful recycling is :)

[GaryD]

Hi Hamish,

Don't get him started......it will be a very large list.


Gary

[Martin A1]

As I understand it.... basically everything! (except the fish :)) Although he even picked up a couple for free recently too....
****** Legend!

[GaryD]

Hi Gav,


This is not meant to cause a flaming warDon't be concerned.....we like to debate issues like those you've raised.


....I'm just interested in whether hydroponics is more or less advantageous than aquaponics, if someone is mainly concerned with vegies and not really interested in growing fish.I've been pondering this very question recently in response to an approach from some vegetarians. Even if you have no interest in eating fish there's no reason why one shouldn't use them to provide nutrients. The notion of a goldfish-powered AP system is not now as outlandish to me as it might once have been.

While some researchers have suggested that a well-established AP system could outproduce an hydroponic one, it's a notion that would have to be very well qualified. A well-managed NFT system is capable of awesome production. Some AP systems produce well.....some times. There are so many variables that it's difficult to be too prescriptive.....and you have to be clear about what productivity means in definitive terms.


Waste:
I can see the beauty of using a waste product as a nutrient source in aquaponics. I was wondering however, if (old) hydroponic nutrient can be used to water certain plants, and therefore become a liquid fertiliser rather than a waste product?Yes it can.


Setup:
I think most hydroponic systems could be setup and closed down very quickly, whereas aquaponic systems need time to cycle - less important if transferring grow media or water. This might be important for people who rent and move a fair bit.Some AP systems can be set up and closed down easily for the very reason that you've suggested. If you use NFT or DWC growing systems in an AP unit, you can dismantle it and move it easily. We do it often. Gravel grow beds are the only impediment to relocation of an AP System. Any other growing system will only require that the fish tank be pumped out before moving it.


Plant varieties:
If the same flood and drain system was used (ie. tank, growbed, grow media, pump and timer), would there be much difference in the variety of plants grown? In hydroponics, one disadvantage would seem to be that plants would have to be grown which need the same nutrient range ie. vine vegies together (2.2 cf) and leafy vegies ( 1-1.5cf) together. Aquaponics however, would seem able to grow different vegies with different nutrient needs.Aquaponics and hydroponics both amount to a compromise when it comes to mixing plants. Commercial AP and hydroponics tend toward monoculture in the interests of meeting a particular plant's needs as closely as possible....with a view to getting the maximum yield.


Vegie Health:
Hydroponics would seem to depend on the nutrients bought and the correct levels of micro and macro nutrients. Aquaponics would seem dependant upon the fishfeed and added nutrients used (ie rock dust).There's a lot more guess work around AP than hydroponics.....particularly at the backyard scale. Commercial AP systems usually add nutrients to the fish water to optimise plant growth. Many such systems do not recirculate the fish water.


Environmental concerns:
Disposal of nutrients is a major factor for hydroponics and a major advantage for aquaponics. On a small scale "used nutrients or waste water" might be used advantageously as a liquid fertiliser in hydro systems.You're right. Disposal of spent nutrients is much less of an issue in backyard hydroponics anyway.....largely because the grower can find something (even if it's only the lawn or ornamental plants) to use the spent nutrient water on.


Fishfeed (good ones) use fishmeal, which is predominantly sourced from fish around Chile. Not sure where the nutrients for hydro systems come.This is the biggest issue confronting Aquaponics - the sustainability of an industry that relies on wildcatch fish meal. This is the aspect of AP that seems to get glossed over when people are singing its praises.

Hydroponic nutrients are sourced from many places....the fertiliser industry .....organic nutrient companies.....backyard concoctions of all kinds....many chemist shops could mix basic hydroponic preparations with what they have on hand. Inorganic salts are consumed by plants regardless of whether we are talking about AP or hydroponics......the only issue is the source.


Cost:
There are different qualities of both fishfood and nutrients. From some research I've done, it would seem that good commercial nutrients would seem available for around $40 for 20L of A and B - enough for a 72 hole NFT system and two 250L small growbeds (offered on Gary and Murray's site) for a year. Good Fishfood (fishmeal LAP free) would seem more expensive - but others might want to comment on this. Also, fishfood feeds plants and fish.I haven't done any work on the relative costs of AP versus hydro. Given my investment in AP (and other food production systems) my fish probably cost $200.00 per kg and the lettuce $50.00 each - my motivation is the desire for clean fresh food.

Gary

[Hamish]

I've been pondering this very question recently in response to an approach from some vegetarians. Even if you have no interest in eating fish there's no reason why one shouldn't use them to provide nutrients. The notion of a goldfish-powered AP system is not now as outlandish to me as it might once have been.
Gary
Im one of the vegetarians who does AP. The way I see it the fish are there to power the veges along with their waste. Dont have to eat them :) but I am sure friends will take them off my hands :) My goal is to feed the fish as much of what I can source naturally and for free - like Black Soldier Fly Larvae from my BioPod that is fed waste kitchen scraps. I will also be feeding duckweed and anything else I can find a good source of for free. Think I will contact local restaurants for scraps to feed the BSF Larvae as the BioPod ramps up. Perhaps even run 2 of them. Will probably still have to suplement with pelet though.

[Sunshine]

I run both hydroponics (ellgrow bed) and AP and find that some plants i.e. lettuces & bok choys grow better in hydroponics and don't run to seed as quickly.

Other do very well in AP and compliment the hydro.

My next venture is into square foot gardening to grow root crops as this is the bit of our diet not produced in the backyard.

[fishfood]

My ap carrots did real well in vemiculate in ap last season

[GaryD]

Hi Sunshine,

Nice to see you around again.



I run both hydroponics (ellgrow bed) and AP and find that some plants i.e. lettuces & bok choys grow better in hydroponics and don't run to seed as quickly. Other do very well in AP and compliment the hydro.

Any hydroponic system that is attached to a fish tank is (by definition) aquaponics. I also use an Ell-gro NFT unit to grow lettuce and it is excellent.


My next venture is into square foot gardening to grow root crops as this is the bit of our diet not produced in the backyard.
You'll love the ability of SFG to handle root crops (and any other for that matter). SFG was my best performing growing system throughout our last summer.

Gary

[Sunshine]

Gary,

I started my hydroponics on the A & B mixture but since it ran out a couple of months ago I use worm tea, occassionally some seasol and a bit of water from the tank and its works a treat. For the purists this is probably crude but it produces lettuces, japanese salads and bok choys faster than we can eat them.

Chris

[GaryD]

Hi Chris,


......but it produces lettuces, japanese salads and bok choys faster than we can eat them.

And in the context of backyard food production nothing else matters. We're doing a similar thing and we find it works, too.

Gary

[Sunshine]

I thought I might post some picks of my hydroponics crop. I planted four rows X 6 of BoK Choy and 3 X 6 of Asian salads as you can see they are prolific. The table has 72 holes most of the rest are a variety of lettuces.

Whilst AP is good its hard to beat this level of growth for these vegetables.

[Hamish]

Nice! How long from seed/seedling to get to this stage?

[Sunshine]

I started planting in late April the plan was to plant a row a week so I would have food coming on line at the same rate.

After a few weeks we started eating but when you consider the bok choys grow three heads per hole X four rows X six holes. That 72 plants.

I could feed an army with that much. Unfortunately the wife and myself don't make up much of an army so there's plenty to give away.

The lettuce story is worse. Particularly seeing we only pick leaves off to make salad mixes rather then cut the whole plant. Once again we have heaps too much.

But as they are mainly fed worm tea they cost nothing to grow.