Backyard Aquaponics
A place to discuss aquaponics

firstly maybe the admins could put another listing in the vast library we have already...that of wicking beds

I have 3 large fiberglass bed frames 1500 x 1000 x 400 Ive spent hours searching here and yootoobing and more confused than ever, some say this others say that...blah blah blah yak yak yak etc.

So if I put 100mm slotted ag pipe in do I put gravel or sand in the corners,

whats your suggestions for the ultimate working wicking bed...

You need storage for water and a way for the water to get wicked up into your mix. Like you, I had to learn how these worked because it didn't really make sense sometimes. Over time I've come to think of sand as a wick but think of rock as being part of the reservoir (some do wick like scoria and expanded clay but most aren't very good wicks). Usually you'll see the rock is under the landscape fabric barrier while the sand is above it to keep it from getting into and filling the reservoir.

I built some wicking beds using corrugated drainage pipe and rock for the reservoir. The rocks were formed into a peak at the middle over the pipe and covered with landscape fabric so the mix could be lower along the side. The lower part of the mix and fabric acted as the wick. http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=13622&hilit=Scotty%27s+wicking+beds

A lot of people use upside down milk crates or drainage pipe covered with fabric as the water reservoir. If they have rocks as part of their reservoir they'd cover these with the fabric as well. Then it's either the mix or sand and then the mix. I think Milne (Food and Fish thread) does a pretty good job with his and there are plenty of other working examples here but usually in peoples system threads. Rob Bob has done a video on how he does his using an IBC (just skip the IBC prep part of the video and go to the layering and it should help - https://www.youtube.com/watch?annotation_id=annotation_911653855&feature=iv&index=1&list=SPBcWprMIwYYizRYZra6RRbe_mrPdnXu4G&src_vid=dCgciRQAXEw&v=vAFyB35yVeA

Tonzz here's how I made my last wicking bed, you don't want gravel or sand in the or anything else that displaces the amount of water in your reservoir.

A lot people fill their reservoirs with gravel or rocks and lose most of their water volume, I can't see the point having a reservoir and wasting most of the water space with rocks or gravel. Use milk crates and get as much water volume as you possibly can, that is the whole idea of the reservoir.

I found you need an air space between your soil and the water, and one of the best things to wick up through that air gap is Hessian, Bunnings sell Hessian by the metre, or use a couple of old Hessian bags.

Your soil can't be any deeper than 300mm, the water won't wick up any more than 300mm. I also run an air stone in all my wicking beds and I found it does improve things quite a bit.

Those handkerchiefs I used in the diagram are meant to represent Hessian that was all I could find when I drew it

jeez 2 conflicting ideas already ... Joblow, IF I went the milk crates do you leave yours full height or cut them down? My large beds will use 10 per bed....8 full ones and 2 cut in half. the ole jigsaw will be busy.

it's a bit like asking what's the ultimate AP system..? lol

My latest IBC wicking bed design is a development of the experimental designs I used in the SY2 bath tub wicking bed.
In effect I'm using the soil up to water level (near the top of the cross tube) as the water reservoir.
When I first set it up I was maintaining the water level between the bottom and top of the cross tube with the hose. Because I had a large direct wicking reservoir I didn't have to worry so much that it would dry up completely.
The next step was to automate the filling which I did with a ball float valve that got the water from the Sy2 ST's return line to the FT. It has 15 min per hour to top up the WB if required, it worked great over last Summer keeping the water level just below the inside of the slotted cross tube allowing air to travel between the ventilated vertical tubes.
Four IBC WB's are all joined together with inverted poly T's that fasten to the base inside the right vertical tube so the water can equalize whether flooding or draining and the flood height is limited to an adjustable elbow tube at the end.

Thank you all so much for posting these solutions to wicking beds. That's actually a lot of food for thought. Are cut IBCs the way to go then?
Brian

Sorry for the confusion Tonzz, I was trying to clarify about the sand vs gravel not suggest using rocks as being a great wicking bed system. I also wanted you to see that there is a lot of leeway in how the beds are built - and yet they still work.

Joblow is right, a lot of potential reservoir space is taken up by the rocks but they are used as part of the reservoir because there is about 40% empty space and sometimes they are the cheapest and most available option. The wicking beds that I built were a lot of work because of hauling rock and on one of them the liner was punctured so to fix it I would have to remove everything I put in. When it's in use, I just use it as a regular raised grow bed - no wicking.

If I were going to do it over it would look like Joblow's diagram.
1. No rocks
2. Large reservoir volume
3. Landscape fabric
4. Wick
5. Mix on top

6. Oh yeah, auto top up like Petesake

Hope this helps.

If you feel like it have a read from here
viewtopic.php?f=18&t=663&start=2160

And from here if you dont want to read all the other stuff
viewtopic.php?f=18&t=663&start=2490

would old underfelt (jute ??) work? ive got 2 mate who lay carpet and both gone fishing so not answering phones..

>> would old underfelt (jute ??) work? ive got 2 mate who lay carpet

Like all modern materials it depends. some underlays/carpet have additives and glue residue etc that are not good for food growing systems. Typically carpet and underlay work best for poly liner setups - beneath the liner to provide protection.
Shade cloth is very cheap on eBay etc and generally very safe. Go with a high blocking / tight weave.


The main thing absent from the setup discussions above is the lack of mention about an external water level control pipe. In all my systems I use a Bunnings bulkhead to provide water level control - this allows you to keep water levels levels down when the soil is wetter and lift it up a touch when you need a bit more moisture.

I used to use the tank outlet but that is too much of a PITA, and the Bunnings bulkhead adapters are like $5.

Also I personally like the idea of a 600-400 cut on the IBC. The 600 is much better for root vegetables etc and you can keep the water level down so they chase the moisture. The 400 is fine for shallow rooted veg and stuff that needs a moist profile over summer.

Lot of talk about the reservoirs etc but one advantage of the coarse gravel type reservoirs is that roots can push down in to it. Sometimes plants prefer that.

Some good discussion on Wicking Beds in these threads (in addition to those already mentioned):
viewtopic.php?f=8&t=24403
viewtopic.php?f=18&t=23402
viewtopic.php?f=18&t=12933 (pages 2, 4-6)

and some alternate options...

viewtopic.php?f=18&t=25556&start=15
viewtopic.php?f=1&t=12708

As wicking beds 'failed', on the don't side make sure your media has an adequate amount of coarse sand or other materials to allow for a degree of air entrainment in the mix (like good potting mix). This may seem like a contradiction when you talk about wicking, however mushroom compost and manure in bathtubs set up as wicking beds (coiled slotted ag pipe with a sock as the reservoir) failed badly ( I must have been having an off day when I thought up that one).

On the up side a milk crate will hold an 8 gallon (US) air pruning bag from China and a really cheap plastic underbed storage unit will fit 2x milk crates.

I will be using milk crates but not enough to cover the whole space in the reservoir, my plan was to fill the surrounds with sand.

You've now changed the way I think and might incorporate an air gap and an air stone.
What do you use to create the air gap? Mulch?

Also, about Hessian bags, I've been using them in my worm farm and find that they break down rather quickly so wanted to know if that was concern?