Wicking Beds

"The wicking worm bed is a highly productive growing system which not only produces more food from limited water, but also recycles waste organic material to provide plant nutrient and capture carbon. The essence is to form an underground reservoir of water or pond contained by a waterproof container or liner below the surface of the soil. Plants are productive because they have a continuous supply of water and nutrients." Colin Austin

We have extreme water restrictions here in Melbourne. All garden watering must be done by hand-held hose, and only on two mornings of the week, so this method of gardening offers a great solution. Water doesn't evaporate in the bottom of the wicking bed it 'wicks' up to the roots, and, the top soil will stay soft, under the mulch. Now, we'll only need to water once a week in summer, and less during the rest of the year.

All of the following information, and more, is posted to my website, here: http://www.maireid.com/wickingbeds.html
The inventor of this system, Colin Austin has clips on YouTube, showing how to do this in small plastic containers, for use in small spaces:
http://www.youtube.com/watch?v=80-dkv1Au-8&feature=channel_page
And here is his comprehensive and highly informative website: http://www.waterright.com.au
Here is another good website, with easy to follow instructions.
http://www.easygrowvegetables.com/
NOTE: I wrote to Colin Austin to ask for advice on the best level for water and drainage, and received a terrific reply, which I've posted (with permission) at the end.

We built our wicking beds using a combination of suggested methods, as follows:
The sleepers, soil, mushroom compost, and rocks were delivered to the front of the house, and carried by the two of us to the north garden, at the back of the house! Still, even with the hard labour, we get great satisfaction from working in the garden and, like all passionate gardeners, we take deep pleasure in nurturing, 'knowing', eating, and sharing our abundant harvests with our excellent neighbours.

NOTE: I wrote to Colin Austin to ask for advice on the best level for water and placement of the drainage hole, and received a terrific reply, which I've posted here (with permission).
EMAIL
Hi Maireid,

Well we have great debates here on this issue of the best depth for the water and soil. Peter (of easygrowvegetables.com) and my neighbour and I spend many hours over a bottle of red wine aurguing this point. If you do not like my answer write to Peter ( [e-mail] ) and you will get a different view.

What we do agree on is that water will only wick up some 300 mm. In my early experiments I had my holes much higher than Peter but I watered until it reaches the holes then I don't water again until all the water has gone. This means that the roots are only in saturated water for a short time. This seems to work fine if the beds are not regularly flooded by rain. We may get a couple of weeks when it rains every day and submersing the roots for that length of time is definitely not good.

Peter had his holes much lower to avoid getting the roots saturated.

Now we are making our beds deeper with about 300mm of soil above the high water line. Using the shade cloth this avoids any problem with water logging.

What we are debating now is how deep we can make the water reservoir. Out last lot of beds were 500mm overall giving 200mm for the water resrvoir and 300mm for the soil bed. This is working fine.

I think that we could make the water reservoir a little deeper still. This cuts down the time between watering. On the latest bed I tried 300m and 300mm. Before, when we had to dig the trench, making it deeper was hard work. Now that we're using raised beds digging is not so much of a problem. Because I am old the last bed I made I dug out all the top soil (about 300mm) then made the raised bed a further 300mm which was quite quick to make.

I have only just put the seeds in so do not know how it will work but I am optimistic. You can see picture on my other web site www.wickingbed.com

I will let you know how it goes.

Sorry there is not a simple answer. It also depends on what you are growing. I guess if you are after a rule of thumb make the soil layer equal to the natural root depth of the plant (for veggies about 300mm) and then decide the depth of the reservoir on how long you want between irrigations, but you will be lucky to get any benefit above 300mm.

Colin

Step 1 The box

Step 1.
We removed the soil from our existing 5x3 meter garden bed and then leveled and terraced the ground for the two new beds, which must be completely level for even water distribution. We put a layer of soft-sifted soil on the bottom for cushioning, and created a waterproof bed for the plastic sheeting (make sure no sharp objects can cut into the plastic sheeting).

Comments

[gwenzpad]

Maybe next time it might be easier to sift using the screen material thats used for windows.

[pfred2]

You're not serious with that sifter are you? Tomorrow, in the light, I'll go out and take a picture of mine and post it to the thread. Nice planter boxes though. Where'd you get the wood for them, and what kind is it?

[maireid]

Crazy eh! We do it all the time in smaller spaces. :) We actually removed a huge lawn on the west side of the house. Ben did most of the hard labour - it took 6 weeks and 2 hours per day to sift what we call kooch grass (Bermuda Grass (Cynodon dactylon) is an introduced weed to Australia) and other weed roots out of the soil. We did that in 2005, and haven't seen a weed since! So, it is worth the effort. The trouble with doing it over the boxes is that we had to bend over carrying the weight of the soil in the tray. Better to put fresh soil in anyway. (One has the old soil, so it will be interesting to compare results. Are you using wicking beds too? We used Red Gum (Eucalyptus). It is super hard wood, and doesn't rot on the ground like treated pine does. We got it from a timber yard in Bayswater, in eastern Melbourne. If that is near you, I can give you the actual address.

[de Oliveira]

Hi mate! To clean your water, you may use bamboo charcoal. It's easy to do.
Use steel drums as oven, the bamboo inside of coarse. Close the steel and put under fire letting out a little steam. Watch until the bamboo turns to charcoal.

When bamboo turns charcoal put in bags (or not) and inside water. Works something like activated charcoal. Replace the bags from time to time. Other charcoal type makes the same job. Bamboo charcoal is better.
The old charcoal can be used as powder to make compost.

If you've there a plant named Eichhornia crassipes, put it in your tank. Well, it needs sun, but makes a net on water, covering all area. Its roots take all hard chemicals and clean water too.
See it: long roots=clean water, short roots =dirty water.

Eichhornia crassipes here:
http://www.ecy.wa.gov/programs/wq/plants/weeds/aqua010.html

http://en.wikipedia.org/wiki/Water_hyacinth

This plant may be used to feed cattle, sheep, as hay.

[pfred2]

I don't have wicking beds. Some raised beds but none that wick. Really I have to raise my plants to keep them out of water. Sadly no Eucalyptus trees around here either. It rained here yesterday so I couldn't get a picture of my sifter, but I managed to get outside today to take one. And another reversed wetter view, from earlier this year. We set a monthly record for rainfall right before it was taken. For scale the frame of my sifter is made out of 2"x4" lumber, so it is about 2x3 feet. I can sift a level wheelbarrow in less than 5 minutes with it.

[djsc]

I have got to make one of these. I assume the frame has something lilke chicken wire in it? I have been using a small plastic garden sieve like Maireid's. Do you return the coarse stuff to the compost heap? I am thinking of wicking beds as a robust, low tech hydroponic system, the coarse portion of my compost is very woody- an ideal medium to go in the bootom of the beds with the finer stuff on top.

[pfred2]

OK the mesh I use is 1/4 inch called hardware cloth. It is welded wire.

The wood frame is half lapped 2x4s.

The way I have my sifter rigged it easily dumps off to the side. When the pile gets too large I shovel it out of the way I guess in the general direction of another rotting pile.

How my sifter is rigged:

A piece of light gauge coated steel cable (got mine from around a defunct pool cover) thrown over round top support bar run to hooks into each end corner. Hooks threaded into sides of sifter frame, pointing down. Set sifter up on 2x4 blocking on wheelbarrow over where you park it then I use a simple knot in the wire to the corner hooks.

Knot looks like this:
http://www.finehomebuilding.com/CMS/uploadedimages/Images/Homebuilding/Departments/021200bs104-01_xlg.jpg

[djsc]

thanks.

[maireid]

Wow! That is amazing! It took me a moment to understand what this is. :) Great! And, yes, the wicking beds are really designed for dry areas - and we are definitely in one here in Melbourne. Where are you based? It looks like a rainforest area. We do have several rainforest regions near us.

[pfred2]

You sound impressed with my sifter. It only took me about a half an hour to hang up. I don't think I live in a rain forest, possibly a subtropical one. Though where I'm at it is a bit too low lying. I live in Delaware USA.

[ellismelanie]

Hello, I have followed the instructions (nice and easy to understand thanks), however now that it is winter I have realised that I forgot to put in drainage holes. You mention putting them in at the end but don't go into any specifics. I was wondering what size, how you stop soil draining out of the hole and how many holes. Hoping you can help as I will soon have raised pools instead of gardens!

[maireid]

Hello Melanie, We made the hole level with the shade cloth, at the opposite end of the bed, — from the pvc watering pipe. We drilled a hole and put in a hose-size pipe with a screen around it to keep soil in. I'd better add this to the instructions. Thanks for asking

[ellismelanie]

Hi mareid, thanks for the information and the quick response, we'll try that this weekend! Cheers

[docwiltbank]

I have been looking for ideas on how to build this type of grow box for quite some time.  I have made a number of smaller ones similar to the earthbox or earthtainers.  But, I wanted to build build larger ones like yours.  My problem was figuring out how to support the soil on the water.  I like your solution of using rocks for that support, it looks like it works.
My question is how do you get the water to wick up from the water resevoir to your soil?
The smaller boxes I have made use a pond basket filled with soil, and rest in the water resevoir.  I suppose a few of those would work in your type boxes.  But, wondered what your solution was.  Or, does it wick up naturally from evaproation?

[maireid]

Yes, the water wicks up naturally. According to the inventor, Colin Austin, water will wick up only 300ml into the soil.

[docwiltbank]

I spent this morning, with my son, building the box.  It is a 4'x8' and 20" tall.  I made it out of composite decking planks.  So, the box shouldn't ever have any problems with rotting.  Next, I'll put the plastic liner in.  I have to go to the sand and gravel yard to get some gravel still.

[swcd]

Hello Maireid, I feel your approach has many strong chariteristics that are positive to a trouble free system. So far my system is "bullet proof". Once in a while I will find gophers that have borough into the beds making a mess. You are right to be concerned about debris in the water. We do not want any solids to collect, even fine sediment. My fear is that the finer the particles the faster the beds will clog reducing the wicking action and life of the beds. To reduce the issue of solids entering the beds, I failed to mention that my storage tank is tilted slightly to allow solids to settle away from the inlet and outlet. Some day I will need to scrape out the solids but that is a long ways away. I operate a re-wholesale nursery that depends on rain and surface water. It is a remote area without electric service,; these beds work perfectly. I also have a 4,000 gallon tank buried to collect surface water. I use a 12 volt pump with a solar panel to drip irrigate my potted trees. Unlike your arid conditions, I live in Ohio, United States where on average we witness two or three months of mild drought conditions. Other times its more rain than you need. Oh! for moderation!

[Paladin]

 putting galvanized chicken wire underneath beds is a good gopher shield.

[maireid]

VERY interesting details! I'll have to consider how to apply your approach in our "west" garden. I'll forward your suggestions to Colin Austin too. Thank you very much for sharing! Sounds like you live in a wonderful part of the world. :)

[swcd]

Glad to see the determination to make it work! I have used the same concept for 10 years, starting seedlings for my wholesale tree nursery. The only twist that I like over your design is: I keep a water storage tank outside of the beds. The discharge line from the storage tank has a inexpensive toilet float valve. When the beds demand water the float does the work automatically. It will drive you nuts adjusting and testing. Once you have the system to your liking, it requires no supervision other than a occasional look to make sure its working to your satisfaction. The key is to adjust the float to the water level of the beds. Your storage tank needs a little elevation to apply the static pressure for the float to function. Great Project!

[maireid]

Thanks for sharing another brilliant idea! Is your external tank covered? I like the internal water reservoir because the water is covered (like a rain-water tank) and therefore won't go off or evaporate.

[swcd]

Good Morning Maireid; Good question, Yes I use a 1500 gallon poly tank that are completely sealed. I bored a 2 " hole at the top of the tank to determine water level when the tank is full. Using PVC plumbing connections I created a trap for excess water to discharge when tank is full. The trap keeps bugs and debris out of the water supply. I prefer the tank to be out of direct sunlight to avoid warm or hot water to irrigate, so my tank is on the North side of the building with shade cloth draped over it. I have about 500 sq ft of bed area. In our area we average 38 inches of rain annually. During July, August, September I probably use around 800 gallon from the tank. One more suggestion; I have two screens staged to act like filters to trap debris from the rain gutters. This is a must from problem free irrigation.

[maireid]

P.s. Just remembered what Colin Austin wrote about the quality of the stored water. To paraphrase, he said that fresh water will push the old water up and out the drainage hole. That makes sense because the agi-pipe is at the bottom of the water reservoir, so water will enter the bottom first. What do yo think of that?

[maireid]

These details are terrific, swcd, Thank you very much for sharing! In one of the comments below, someone here suggested I put a lid on the pvc pipe entering the wicking bed reservoir. I used a jam jar lid. :) That means the only other hole is the drainage hole and we put a filter on that so bugs can't get in. The water reservoir is under the soil, where the heat can't get to it, and bugs can't get in. The shade cloth acts as a filter between the soil and the reservoir. Naturally the soil will dissolve into the water. I have been wondering what that will do - meaning to write to Colin Austin and ask him what he has experienced over time with the water quality. He is in China at the moment, so I'll wait a while. We are based N.E. of Melbourne, Australia. Our area is in a long-standing drought, with severe water restrictions. To say the least, our water management polities don't reach high level-engineering standards. We mainly depend on dams! I'll have to look up our average rain fall figures. Suffice it to say, most of it goes down the storm drains. Where are you based?

[larsrc]

While I've never seen them in the US, containers with the same principle are marketed in Denmark and has been for at least 20 years. Styrofoam containers for the water, where the lids have three tubes down to near the bottom. You place a sack of compost on top, make holes to match the tubes, press some of the compost down, and plant (typically) one plant on top of each tube. I've grown tomatoes and peppers that way with as much success as can be expected for the climate. See for instance here and here

This instructable has the advantage of scale and more reusability, but I see no way to clean the water part, which could become a problem over time. In smaller scale boxes, they can be made to be taken apart for cleaning, but not on this scale.

[maireid]

Yes, I've seen many variations. Re. keeping the water clean, because the water reservoir has only to openings, the filling pipe and the drainage hole, the water stays clean –like in a water tank. Plus, the water is flushed when new water is poured in.

[the rural independent]

This is a fantastic, well written article. I really appreciate the level of detail that you provide. I have been using a home made "eco-box" this year and have had great luck with six tomatoes per 21 gallon container.

Next year there WILL be a Wicking Box in the yard for sure.

On the water level / floatie thing, I think that nillo's suggestion is great and will be incorporated into my design.

Thanks for sharing!

http://www.theruralindependent.com

[maireid]

After visiting your website, I am all the more thankful for your compliment. I am going to join your forums.
The comprehensive level of coverage and easy access to information on so many issues of interest is very impressive. You are welcome to use my report if you wish. The full report is on a single page on my website, here: http://www.maireid.com/wickingbeds.html

[Skip]

Awesome idea. You could easily set an aquaponics setup to this.

[maireid]

I don't know anything about aquaponics. How would you do that?

[capheind]

Aquaponics uses fish to add, um, "Organic Matter" to the water before it is used in a Hydroponic system, in lieu of, or in addition to, the normal nutrient mix. You could merge an aquaponic system into a Wicking bed by adding an inlet and outlet to the bottom of the bed so the water can be cycled through a pond. Or you could build a pond deeper into the ground coming right up to the level of the rocks, and then create a pass through between the bed and raised pond.

[the rural independent]

We have a small pond with fish in it and I take pond water out in a pitcher to water the tomatoes and also some flower boxes. The fertile water is much loved by the plants - great design idea capehind!

http://www.theruralindependent.com

[maireid]

Wow! That is a brilliant idea! I'll see if we can do that with the next wicking bed we build. Thank you sharing for that idea!

[capheind]

I'd love to try it myself but I don't have the space. I'm an apartment dweller. If your a piscivore I'd recommend tilapia, their very easy to keep, relatively easy to clean, and can even eat some of the veggie scraps from the garden.

[maireid]

Well, if you look at Colin Austin's YouTube links, (see my opening notes for the links) you'll see that he shows how to build small wicking beds, in ordinary black plastic tubs, that would be easy to keep on a small deck, - as long as there is adequate sun–at least 4 hours a day. :) I'll look into your suggestion too. Thank you again!

[capheind]

Well I have a small bed here at the complex, and piles of potted plants already filling my patio.. but when I have room I'm always up for a new experiment..

[maireid]

Absolutely! Have fun! :)

[nillo]

You could make a float to tell you what the water level is. Just get a big cork and drill a hole in the middle. Stick a piece of balsa wood through the hole. Place the float in the PVC standpipe. Try to use a big cork that is almost the same diameter as the stand pipe, and make sure the balsa wood stem is long enough to stick up over the top. Just paint the balsa wood stem for visibility and you will know how much water is in the reservoir from 10 feet away.

[larsrc]

Good idea with the flag. Thank you!

[maireid]

What a terrific idea. I'll try that :) Thanks!