Backyard Aquaponics
A place to discuss aquaponics

I've done a bit of digging around, but I can't decisively find if anyone has used coco coir as a growbed medium when they have a recirculating system. I've got a bag, and I'm trying to put together a small tower growbed. I ruled out gravel because it's heaveir than I can deal with, but I am quite attached to having a pretty natural medium.

I'm alternately very worried and not at all worried that it might be detrimental to my little fishies. I wouldn't want to hurt them...life is hard enough with somebody using you for your pee.

Any words on coco coir and how it works out in a recirculating aquaponic system?

Thanks a million!

Stellar, welcome to the forum.... there are quite a few APers using cocopeat in one form or another, one way or another......

Results from those using it are a definite thumbs up....

I don't think a lot of people have used it for great lengths of time so there are some possible long term unknowns as to how long it may last etc... suspected to last at least two years...

Points to remember...

(1) It will drag your pH down i.e it's acidic...

(2) It will require washing or will colour your water.... washing because it's often been soaked in saltwater.... and therefore can be quite very salty.... given that people often dose their newly arrived fish this may not be a matter of concern.... just be aware of it

(3) It holds water really well... so you may have to throttle back on your water rates a bit

(4) It can trap sediment/solids and cause a film over the top... maybe not a huge problem and probably depends on how coarse or finer grade you have

As far as your fish are concerned.... check your label to make sure it's not a "store" packed block with added fertiliser of some sort....

If it's straight coc-peat no problems at all....

Just be wary of some of the orchid type mixes available

Hi Stella.

I have been using coco peat for 6 months or more now with very good results.
It does/will discolour your water , but this gradually subsides. The fish (Australian natives ) don't mind the discolouration one bit, in fact I think they are more comfortable...able to hide better etc.
Here in Australia it is avbl with little or no salt content being harvested from inland coconut plantations.
Retains moisture very well, drains exceptionally well, but by my observations I feel the good bacteria colonies do not so readily or quickly form in coco peat as they do in gravel grow beds, so I feel that it is not a replacement medium for gravel, but an good addition to a standard system
I am running a grow bed as a open-loop at the moment with very good results. I have carrots and potato, both ordinary and sweet potato growing in coco peat. The growth is great. I am a month or six weeks away from harvest, so the final info is not in yet, but so far it's looking good.

I have not experienced the drop in pH that RupertofOz speaks of, but that may be just because of the particular coco peat I have sourced.

The grade (coarseness) I am using which is from 8mm chunks down to 1mm blend has not caused any blocking. As RupertofOz points out, this would be a problem if the very fine grades usually sold as seed raising mixture were used.

Muzza.

Hi murry let me get this right you started running coco pete and thats what discouloured your water now your coco bed is open loop how often do you water now i am interested running some too for spuds and carrots

Humm... bit confused as well Muzz... thought your tank water was discoloured because you were using the cocopeat... implied return to tank from drain cycle

Have you subsequently removed the cocpeat bed from your system into an "open loop"

If so could you outline your reasons for us....

Is it because you feel ...

You may be correct with this observation Murray - but I am interested in what you observed specifically that led you to this conclusion.

Am eager to see the root crop results :-).

If gravel is too heavy, consider a blend of hydroton and gravel. Hydroton is expanded clay pellets that will not break down. They do float a bit, so I have gravel on top of mine to hold them down. Still pretty heavy, though. Coco coir would no doubt be lighter.

how about coco coir plus gravel

Thanks for the responses!

Murray, I'm curious to know as well if you started with the coir bed recirculating and then decided at some point (wanted to see your fish again, just to make sure they were there?) to take it out of recirculation?

Right now I really just want to use it for a 3-foot tower over my 10 gallon aquarium. Playing a bacteria host isn't a huge issue as I've got the biofilter worked out with the aquarium's standard filter pumping into a little yogurt container full of gravel. But if I'm going to have big pH and/or color issues this might be a problem. Do you all have any other medium suggestions?

I guess the criteria are: light, cheap, functional, harmless to fish and water quality, will facilitate growth in my basil that breaks a hole in the roof overnight, umm, oh yeah and gives my fish feet so they can walk over and get their own food. Plausible, eh?

Nothing is unsurmountable Stellar.... and issues like ph are more a matter of awareness and adjustment where required....

Water colour is like beauty... in the eye of the beholder... as Murray says, many fish like a darker colouered water,,, whereas others like trout may prefer clearer waters, probably for oxygenation reasons more than anything

See Steve SS.s thread HERE for more discussion of cocopeat and washing etc...

Go for it...you can always ask for more inout as you go

The primary reason I changed that bed to open loop is that I want to be able to see the fish. I have loads of visitors to see my system and some of them (the visitors) did not believe that there are fish in the tank, and let’s face it, a big part of the fun of aquaponics is watching the fish.

I have had the bed closed loop and open loop several times just to see what happens. I feel it is better in an open loop situation.

I came to the conclusion re the level of bacteria colonisation by simple observation. Planted identical seedlings Tomato and lettuce in a gravel bed and a coco peat bed at the same time.
Growth in the coco peat not as good as in gravel.
I admit that there may be some other factor, like the coco peat not liking so much water going through, but that would require more scientific/controlled observations.

Watering. I water the coco peat by hand once a day using water from the fish tank. In the hot weather it gave it 8 ltrs a day, (probably more than it needed) now it is down to 4 ltrs a day for the 585 ltr grow bed. I feel I really only need to water the coco peat every second day actually. It holds moisture really well.

The plants appear to be doing better since I took it out of the closed loop watering.
I am feeling at the moment that when it was in the closed loop watering regime that there was just too much water for the coco peat to function correctly. That and the feeling I have that the good bacteria does not form as well in coco peat.

Once again, I stress, these are only my observations, I do not have any hard testing to prove anything about coco peat. Someone else may have different ideas.

I must also confess to a major sin. I have once given the coco peat bed a hit with “Seasol”. I noticed an improvement in the plants in the following days. When it is open loop that kind of thing can be done without a worry.

I feel very happy now to have a number of beds filled with coco peat hanging off the side of my main gravel grow bed system, to grow root crops etc.
What I am trying to devise is a system of delivering around 3 - 4 ltrs of fish water once a day to the coco peat beds, automatically.

Murray

nothing wrong with adding Seasol to a system

I'm a little curious Murray, you are feeding 8L of water a day to your peat beds out of your fish tank, yet your total water consumtion for your system is only 10L per day?

Was, not now.

EB, I initially pondered the same question when posted in the other thread,

However Muzz does explain (above) that over time he has learned that the peat requires much less water and frequency of watering than he initially applied



I'm still surprised that evapaoration and transpiration from his other gravel bed doesn't account for more water than that though....

Perhaps Muzz is only reporting the water consumption that he's actually measured... ie the cocopeat