Coco Peat use in Aquaponic systems

[Murray]

My coco peat bed is doing great. I have recently pulled two potato bushes out and was a little disappointed with the harvest from them. I had about 30 potatos from the two bushes but the potatos were all very small. The variety was "Pontiac" one of those red skinned types.
Perhaps some expert potato grower can tell me how this may be improved.

Italian parsley, ordinary parsley, sage, and carrots are all growing well. I have harvested some carrots and they are coming on fine although carrots are not fast growers.
Some photos to see how it is all going, attached.

[gbj]

Hi,
I like the idea of using coco peat as a grow bed because it is light, but when i have used it in the past as mulch, it tends to break down into a fibrous, soil-like mass within a year or so, which, if i understand correctly, would not be good in an aquaponics system. Is it your intention to change the peat over regularly or has that not been a problem?
Just asking theoretically at this stage, haven't set up a system yet
Thanks

[Murray]

GBI,

I have found coco peat to be the most wonderful grow medium. It is not a replacement for the standard gravel grow bed, but should be viewed as an additional element in an aquaponics system.
I have had one bed of coco peat for more than 6 months (I can't be exact about that time frame) but a long time. I have not witnessed any breakdown as yet. If in time it does get broken down a bit, perhaps by the action of earth worms etc it will be easy just to add a bit more to the top of the bed at the end of a crop cycle.
When setting up my coco peat grow bed I laid down a raised row of gravel in the middle of the bed first. Raised about 75mm and about 200mm wide for the length of the bed. Then as I added the coco peat I also placed around the drain up stand a barrier of about 100 mm thick of gravel. The fines in the coco peat were therefore prevented from making their way into the drainage up stand and causing blockages, and the raised row of gravel for the length of the bed was to aid drainage.
I am not sure that I needed to put the raised row of gravel in the bottom, but the gravel around the up stand is very necessary.
I feel that coco peat is just the most marvellous product and is yet to be fully utilised in home food production methods.

Actually, one of our members "Ulatawa" is a bit of a coco peat expert.... perhaps he will post some info.

Muzza

[gbj]

I'm going to try your method with an old bathtub that I'll hopefully get hold of in a couple of weeks (just a plant bed, no fishtank as yet). In the FAQ section I read that the water can get discoloured - is this a problem for the fish and how do you deal with it?
By the way, many thanks to yourself and GaryD for setting up and maintaining this informative and friendly forum (and to anyone else who is putting in a lot of work in this).

Cheers, Gabrielle

[njh]

I did an experiment over summer comparing cocopeat to potting mix for striking cuttings:
http://njhurst.com/~njh/blog/coco-peat-for-cuttings

My conclusion was that cocopeat was worse for making cuttings than potting mix. However, that doesn't mean it isn't suitable for AP - for a start I was watering with rainwater, which might lead to faster nutrient exhaustion in the CP. Indeed my next experiment was to be a flood and drain cuttings system using cocopeat and AP water, but I haven't got time now (going overseas in a week and it's too dark for cuttings anyway).

So if someone else would like to run an experiment...

[GaryD]

Hi,

Coco-peat comes in a variety of grades from that which is very fine to quite coarse chips. Every grade is useful for something or the other in AP.

The very fine stuff is good for seedling propagation. It will definitely discolour water.

The mid range material is excellent for growing a variety of plants particularly in open loop systems where discolouration of water is less of an issue. We use this material in our satellite pots and growing trays.

Both the fine and medium grades have excellent water retention and so this further disqualifies them for use in recirculating systems.

The coarse material or chips may be useful for recirculating systems - but I have yet to confirm this.

As good as coco-peat is, there are a couple of other issues to be aware of:

• Some brands may contain high levels of salt.
• All coco-peat has the capacity to strip calcium and magnesium from any nutrient solution that has contact with it.....unless it has been buffered to prevent this.

These shortcomings are easily addressed and are far outweighed by benefits of coco-peat.

One of the major benefits is its total recyclability. In our Integrated Backyard Food Production concept, spent coco peat is used as deep litter for our quail and chickens. When it is thoroughly mixed with poultry manure, it then becomes worm bedding.....and eventually worm castings and worm tea.

GaryD

[anniefish]

Hi,
I think you would find coco-peat would hold too much water to be good for cuttings which generally need a drier medium, I usually add fine gravel or perlite to my potting mix for cuttings and keep them on the dry side. Usually put the pot in a plastic bag or pop a cut up soft drink bottle on top of the pot to make a small terrarium. I think it would be a great medium for grow beds. Hope this helps. Would be interested in where to buy the coarser coco-peat.
anniefish

[Murray]

Some can be seen here. http://www.aquaponics.net.au/prod58.htm
Also, I have PM,d "Ulatawa". He knows a bit about coco peat and where to get it from. He might be able to help with some info.
Murray

[anniefish]

Hi Murray,
Thanks for the info. Setting up the shade cloth today. Will get in touch when we're closer to setting up the grow beds. By the way how many members now? Thank you to you and Gary for a great site.
Ann.

[Murray]

Below are a couple of photos of my one coco peat bed.
The day of planting which was 31st October 2006 and a following shot of the same bed on 22 December 9 weeks later.