Using pipe as grow beds.

[craigb]

In my wanderings around the net, I noticed a few AP systems using 90, 100 and 150mm pipe filled with gravel with slots cut in them as grow beds.

From what I have gathered it is recommended that a minimum depth of 300mm is needed for an effective grow bed.
Is that depth necessary for the conversion of bacteria into nitrogen?
For the plants roots to have space to grow deeper?
Or to have enough volume to keep reticulating the tank water?

I have just cleared the side of the house where we are intending to put in a fishpond - we intended to do so before I become interested in APwith the idea of making a series of rockery gardens that will flow back into the pond.

I was thinking that pipes could be utilized on a frame stacked up above one another to grow strawberries, lettuce, bock cho etc. If the volume in the pipes wasn't enough to filter the water it could be then released through the gardens to flow back into the pond.

What do you think?

[Murray]

Shallow grow pipes do work especially for short rooted plants such as lettuce , strawberries and the like.
300mm deep grow beds are particularly suited to deep rooted plants like tomatoes etc.
There does not appear to be any hard science behind the 300mm deep thing, it is just what has been done for ever (almost) going back to the early modern day pioneers of Aquaponics
See this website

I am a great believer in the old adage, "If it aint broke, don't fix it"

I know from my own experience that a combination of 300mm deep grow beds and some modified pipe beds works just fine.

[craigb]

Thanks Murray.

I'm in the process of digging the fish pond. I'm going to concrete it and then line it with a pond liner. My wife is a little dubious about the AP concept and as we have been talking about putting in a fish pond for a few years I'm going to adapt it to AP usage making grow beds in the rockery as well as using pipes.

I'm thinking a herb garden will look rather interesting around the fish pond.

I am going to raise the pond above ground level which will keep ground water out and it will be between 1000 and 3000 litres. I'm planning to divide it with some fine screen mesh to keep yabbies in one section and fish in the other, with a smaller pond above it (300 - 400 litres) which I will use for a fingerling tank. I need to work out how I can cascade the water from one pond into the other without losing the fingerlings from it, keep enough water in it and yet have enough water flow through it to keep it clean. A mesh screen again might do the trick.

There are a few problems with it compared to the standard system, one being the beds (Rockery and pipes will be in the open and not covered, the other is that it is being built between two paper bark trees which drop a lot of litter. I'm going to cover the beds with weedmat with perhaps a thin covering of gravel over them which will make cleaning up the debris easier.

The ponds will be a little more difficult to cover, though the smaller one I'm thinking of building a type of paddle / water wheel house over it and the larger one a cover of some description.

I'm hoping to borrow my bro's camera shortly to post up some pics

[Murray]

It will be very interesting to see some photos, that's for sure. How fine will the mesh be ? If it is too fine it may tend to block up...perhaps