I?ve been posting the same information on various threads over multiple forums recently so here?s a monster post to put some of it together. For those of you who are new to the concept, aquaponics is a way of turning fish poop into plants. It is widely used as an intensive farming technique to produce cheap edible fish and food crops the same theory can easily be applied to a home aquarium. The main benefit is nitrate/phosphate removal and plants grown hydroponically can outcompete even algae for those nutrients. The plants will also remove ammonium and nitrites so when used alongside conventional biological filtration it creates a very stable system.
Note: It is possible to grow both hydroponic and aquatic plants with the use of fertilisers and careful water management but it can be tricky.
How it works
Any system that gives a good flow of oxygen rich water over the plant roots will do the trick but pictured below is a fairly standard set up. Water is pumped from the aquarium and into a spraybar, which trickles water over the surface of the planting media. A drain at the bottom of the planter returns water to the aquarium.
Ready-made aquaponic systems are not widely available but HOB or overhead filters can be used with no modifications. Plant roots will not disturb the bacterial action in your filter so the same filter/planter can support both with no need for additional kit. If possible replace filter sponges with hydroton or ceramic media for easier filter maintenance and replanting. Once the plant roots grab hold of a sponge it?s quite an effort to remove them! Filter bacteria aren?t fussy and like plant roots can be grown anywhere wet and with a good oxygen supply, just be sure to use something with a large surface area.
Extra light is not strictly necessary but is highly desirable. Plants will stretch towards any light source nearby and that may be the tank underneath so even a small light source above the planter will make plants grow in a much more orderly and attractive way.
The latter being a few months after adding a 3w led wall lamp.
With more intense lighting you can grow a much wider range of plants. Suitable light sources can be anything from a small desk lamp to a proper grow light; a colour temperature of 6400k (daylight white) is preferable but not required. Photoperiod does not seem to be very important, 12 hours is fine.
Less is more when it comes to planting, it?s difficult to give exact numbers but the uptake from a small established peace lily is considerably more than the output from a male betta. To keep the system low maintenance it?s best to plant *very* lightly to start with. It can take about a month for a plant to adapt to being grown hydroponically so be prepared to wait a while for uptake levels to stabilise. If the uptake from the plants is too high you can either cull some of the plants or add fertilisers to the water column.
Plant just as you would in the aquarium or garden and remember to keep the crown of the plant dry and on top of the planting media. The plants may well be floppy and need to be propped upright but they should root within a week or so. Fertilisers
A liquid trace fertiliser for aquatic plants will ensure that the plants have access to all the minerals they need, start at double the recommended weekly dose (for aquatic plants). Additional fertilisation may not be needed but if the plant uptake is higher than fish output you may want to consider dosing macro ferts. Any liquid aquarium fertiliser that contains nitrates and phosphates will work but again the dose may need to be higher than recommended on the bottle. As plant uptake will vary depending on size, species and growth rate, dosing must be done on a trial and error basis. High nitrate levels are harmful to fish so its best to start with a low dose and work up, you can use a nitrate test to gauge how quickly the fertiliser is being used up. Adjust the dose of trace fertilisers relative to the dose of macro fertilisers.
Note: Seasonal light level and temperature changes may affect growth rates and uptake of ferts. Be prepared to balance out seasonal fluctuations with water changes or fertilisers.
There is a huge variety of plants that can be grown this way, including chilies, strawberries, herbs and common houseplants.
These are some plants tried and tested by me that will thrive with minimal light/care:
Need a little extra light (I used a 3w led spotlight about 6 inches from the plant) and do less well when starved:
Wandering Jew (Tradescantia blossfeldiana) Pineapple mint Pilea 'moon valley'
Plants that failed to thrive:
lace fern begonia rex spider plant (grew new leaves but never rooted well, may be worth another try) ginger mint chocolate mint (shame it smells amazing!)
If choosing your own plants to experiment with look for anything that grows well hydroponically like basil, oregano and tomatoes. Houseplants are usually popular for their ability to survive abuse so most of them are good candidates too. Many aquatic plants can be grown emersed but not all can survive low humidity, those that can need to be carefully acclimatised.
Please post your own successes and failures so that the plant list can be extended. My enthusiasm for this topic far exceeds my experience and while a lot of people use or are interested in aquaponics, it can be tricky to find information. All input/questions are welcome.
Fantastic thread, great post - just what I wanted to see.
Inspired by your experiments in this field, I am planning to do something similar with one of my (currently empty) tanks. I was going to start asking you about it when I get that particular project under way, but you've beaten me to it.
Excellent post! Two of the major (or macro) factors with aquaponics are your source of phosphates and potassium. Commercially potassium is often the problem if you try to keep things organic (some people even use banana's!). Your phosphates come from the fish food, but as you've noted may run low.
Do you have any interest in hydroponics, or more interestingly for me, hydroponically kept aquatic plants?
My phosphates mostly come in a bottle, I dose macros about 3 times a week XD
I have a passing interest in hydroponics, I'm sure one rainy day I will rig something up with old icecream tubs and stuff from the fish cupboard. ATM I'm more interested in edible and carnivorous plants as hydroponic/aquaponic subjects. Now Ive gotten to grips with the basics I want plants that offer something extra.
Cathy i was looking at something like that as i have a spare hob filter, but its a long process so may take some time. trying a few diff ideas after speaking with Onyxia. as i have a spare 70ltr tank which will be kept in a heated conservatory, which i would love to try this with, just trying a few designs.. as its just glass top sliders and an external filter at the mo..
Knowledge is knowing that a tomato is a fruit, wisdom is knowing not to put it in a fruit salad! I dont keep fish i keep water the fish are only there for decoration
I'm thinking about redoing my HOB (again), when I do I'll take photos and do a step by step guide. I really want to have a go with basil and I've seen some stunning h.leucocephala that would cover the yicky sponge that I use as a water baffle.
My vague notion at the moment is to have a (home made) 3D background and build it with an overhang at the top. Plants will be in that overhang, in pots, and probably surrounded by ceramic noodles or similar. I'll use an external canister for tank filtration, but have the return pipe run into this "overhang" compartment with a waterfall at the end to run it back into the tank.
Will this work or am I in error somewhere along the way with this?
Fishlady wrote: My vague notion at the moment is to have a (home made) 3D background and build it with an overhang at the top. Plants will be in that overhang, in pots, and probably surrounded by ceramic noodles or similar. I'll use an external canister for tank filtration, but have the return pipe run into this "overhang" compartment with a waterfall at the end to run it back into the tank.
Will this work or am I in error somewhere along the way with this?
Sounds very interesting. If you use pots it will stop the plants getting as many nutrients and oxygen from the water column. You could solve that by using baskets or you could fill the pots with soil, cap it with gravel and grow bog plants. If you want to do the second one google 'riparium' for inspiration and plant choices.
If this is under the hood it will let you grow plants that like high humidity, including swords and crypts but may not be as good for herbs etc. Both my set ups are low humidity so SO19Firearms may have more to add.