Backyard Aquaponics
A place to discuss aquaponics

I've been watching JT, Food and Fish, and Jessie build their wicking beds to get ideas but decided to go my own route, which usually means it will cost a lot and this was no exception (for what they are they aren't that expensive but I wasn't able to source some parts and made one or two design changes that cost me). Certainly JT's wicking beds would work as well and be much less expensive because of the recycled parts.

I build two slightly different models of wicking beds using corrugated aluminum roofing, angel iron, cedar and rebar (plus lots of tech screws). The liners were the same for both models but the bed construction was different.

My model for the large wicking beds is located here - http://www.noble.org/ag/horticulture/raised-bed-gardening/corrugated-beds/.

The small bed is similar but without the wood frame and rebar. On these I only used a single pair or rebar and some plastic coated clothesline wire to hold in the center of the bed per a suggestion by Food and Fish on Jessie's thread where he suggested 8 gauge wire.

First this is where I am at with the build. The two large beds in the foreground will be bucket gardens for the time being - all the other beds will be wicking beds.



The large beds are 3 X 15 and the small ones are 3 X 8. I requested roofing panels (which are 26 inches wide) in 3 ft and 8 ft lengths, then ripped the panels to 13 inches wide on a radial saw with fiber cutoff disk. Here is a small bed showing the basic construction - this is basically as Jessie did - aluminum roofing with tek screws going outwart through this into 2" angle iron. Flashing could have been used instead of angle iron and it might have been cheaper but I like the way these look.



I used an angle grinder to remove the screw tips and then touched up the paint on the angle iron (I used hammered black paint on the angle iron - the aluminum roofing came already painted green on the outside and white on the inside - color choice is yours when you factory order). The aluminum roofing was 2.06 per linear foot so this is really inexpensive. Running the screws inward into the bed as directed in the Noble Foundation website works for beds without liners (which is what they are doing) but running them outward is pretty much a necessity if you have a liner. I tried it both ways and the corrugations make it difficult to remove the screw tips on the inside

For the large beds I prepared cedar 2X4s with holes for rebar bracing every foot (original plans suggested 9 inch spacing for rebar and 12" if using sucker rod). You might want to go with the tighter spacing if you try this - I had already drilled the holes before finding I had to use rebar.
Before attaching the wood frame to the aluminum bed I drove some 40" rebar through the holes, into the ground and used vice grip pliers and a level to set the height and level the sides.

Level all the wood frame sides this way making certain that they overlap properly in the corners. I joined them in the corners using pocket hole screws and a Kreg jig. You can see the pocket holes for the screws in the last photo of my previous post. Note the screws go into the side of the adjoining boards not the end (screws pull out of end grain much easier). If you don't have a pocket hole jig you might have to do it the other way.

Once the frame is together and level, drive all the remaining rebar in till it is flush with the top of the 2 x 4. Cap this with 1 x 2 as per the Noble Foundation site and you will have locked in the level and height of the growbed. Join the aluminum bed to the frame using tek screws - mark a line on the frame for the top edge of the aluminum so that it's fairly even.



Note - In the picture above I reversed the screws in the angle iron on the corners after I took this shot so don't do yours this way unless you're not planning on a liner.

Here's a shot showing the tek screws holding the bed to the frame. This also shows the overlap of roofing to make an extended bed.



From here you are ready to lay the liners out..

Here are the layers I used.
1. Pond Underliner
2. two layers of plastic
ROCK - 3/4 inch river rock
3. Weed block fabric
Commercial Potting Mix

Pond Underliner with plastic laying toward one end of bed.



Plastic layers down with pipe and 3/4 river rock on top. Note the shape of the rock layer - This type of rock doesn't wick to well so I'm going to use the lowest portion of the potting mix as the wick. There are channels on either side of the pipe for the wicking portion. Another important thing is I filled the bed with several inches of water (up to where my drain hole would be). The water acts as a cushion when you are adding rock and makes it less likely that you will pucture the liner.



Over the top of the rock goes the weed mat - this one is only 4 ft wide - 6 ft would wide have been better but this looks like it will work.

It's time to attach the drain pipe. I used a 3/4 inch fitting with an O ring on the inside - I believe they are electrical PVC but I've had them so long I'm not sure. I had drilled the roofing material for a drain before adding the underliner. I filled the bed with enough water that the underliner and liner would push out against where the hole was and then from the outside I used a utility knife to cut along the edge of the hole until the hole was clear. I then installed the fitting. I used an elbow and small piece of PVC to set the depth - these are loose so the water depth can be adjusted from outside the bed by rotating the elbow or changing the pipe length.



Finished with the potting mix over the top of the fabric and pushed the fabric to the sides as I did so, to prevent the mix from getting into the rock bed (this is why a 6 ft wide fabric would be better). That's it for now.

Thanks to the Noble Foundation and Steve Upson for providing the original design and inspiration for these beds. This was the model I was working from - I wasn't clear in my first post on this, they have done an excellent job of putting together a plan and materials list and construction method, these helped me get going. Some of the details were inspired by other AP'ers like Jessie, JT and Food and Fish, Kudos go out to them. Thanks.

Great job scotty, they look like they are supposed to be there.

Thanks for the details! Looks great!

looking good......

it has a sort of industrial look, as mine looks barnish

any reason for using rock instead of sand?

I like the adjustable overflow.... I may have to use that one

thanks for the pics

jT

Thanks for the comments, glad you're getting something from these posts.



Not really, sand vs rock was a toss up for me. Either would work but I felt the rock would be a better reservoir and the sand would be a better wick (intuitively this seemed right although I'm not certain which holds more water) - I wasn't using milk crates and figured I could use the potting mix as the wick since the sand only carries the moisture up to the boundary anyway. I thought about placing sand in columns strategically around the bed in the reservoir so that I could pull water from the very bottom of the reservoir but decided I could add this later if needed. I think if you've already got a large reservoir, like in your setup, sand is the way to go because you get more uniform wicking.



This was something I found on another website, where it was mentioned but not pictured - made a lot of sense to me as well. It's pretty nice because you can put the drain low on the bed and look down the pipe to see where the water level is.

One other thing nice about the large beds is that they are leveled to each other so you can put a board between beds and sit down to work or use the board as a tray.

Just an update on these. I've been getting ready for the first freeze of the year and cleaning up little bits and pieces but I'm still not done. Here are a few pics so you can see the progress.







The hoops are two different sizes (the South beds have lower hoops than the North beds). North Beds use 10 ft of 1/2 PVC for the hoop and 23 ft sections of Nylon rope looped behind the rebar on one side and tied off on the other. The South uses 8.5 ft pvc (I think this is right) with 20 ft sections of rope. The rope holds the plastic tight to the hoops and the 1/2 inch PVC hoops just sit in holders made from 1" PVC pipe. The sides can be adjusted for ventilation and are easy to close by just sliding the plastic down the pipes. I have found that small spring loaded pinch clamps (6 for $1) from Harbor Freight help with keeping the plastic sides open so that I don't have to readjust the tension on the ropes unless they are very loose. I'll post a picture with clamps shown when I have time to get another picture (they are the 7/8 inch opening version).

wow, those beds look fantastic !

looking good dude, nice job.

Nice looking beds!!!

Thanks everyone. Now that I'm close to being done with them I'm really glad I made them. There might be better ways to do the reservoir though, especially ones that don't involve hauling 4 cubic yards of river rock .

BnBob, thanks for all the great information on your videos and website. I spent a lot of time looking at how your wicking beds were built and watching some of your other videos as well

This hoop setup would work for most raised beds that have a wood top edge (just a little modification required). The rope keeps the plastic tight and lets you slide the plastic wherever you want for ventilation but it is all manual (This is a type of caterpillar tunnel). Look on the Noble Foundation website (link in my first post) for how to do this - they have a link for this mini tunnel which is where I got this idea.

Hi Scotty, You've been using your wicking bed for a few years now, can you post any updates? Any lessons learned or things you would have done differently? I think the adjustable water outlet would be key here in the Arizona desert for salt buildup removal... Have you had any problems with salts in your system over time? Thank you so much for posting all those photos - such a great inspiration.