Building my Wicking Garden Bed
By Raymond Jess
Updated: May 2017 with new pictures at bottom.
Check out Wicking Beds 2.0 and Wicking Beds 3.0 next!
I discovered wicking garden beds when I did volunteer work at the home of a local Master Gardener. She had four big beautiful beds filled with exceptional looking vegetables and I was inspired by the wicking bed concept.
After talking with her about the garden beds, I did some research and found a few articles which gave me the basic information I needed to get started on my own garden project.
I was so excited about the possibility of having a wicking garden bed of my own, I put together a diagram of my yard and got started right away. I must say, my finished product turned out better looking than I expected. My plan was for a 4’ X 8’ garden bed. With the help of a good friend and her truck, we were able to get the construction materials home from our local hardware store. It was not an inexpensive project for me, but only because I wanted all new wood even though re-purposed wood would work just as well.
I used 2×12 pine boards, that I stained for color and protection. Because I wanted the bed to be two feet high, I used 4 boards eight feet long, and 4 boards 45 inches long, to make the basic box. For support, I used 2×2 pine boards on the inside corners.
Once the basic box was constructed, and before I put in the liner, I put a base layer of sand in the bottom to make sure no rocks or thorns protruded. Then I put in the liner. Because we live in the southwest desert and I wanted the bed to last, I decided to use heavy pond liner instead of thinner plastic sheeting. The thinner plastic will degrade and leak due to heat.
I drilled a hole for the bulkhead fitting, covered one end of the fitting with shade cloth to keep bugs out. Then I put a 90° elbow on the other side and attached tubing to act as an overflow and water level indicator. Because of our hard water and the build-up of minerals and salt, our beds should be drained and refilled twice a year. The 90° elbow is able to be rotated to facilitate this draining.
The design requires a fill tube so I used 2-inch PVC pipe. I capped one end, cut it to the desired length and put a 90° elbow on the other. I used the remainder of the tube as the vertical pipe which extends above the level of the planting medium and has a cap to keep the bugs out. Several holes were drilled along the length of the bottom of the pipe to allow the fill water to flow throughout the length of the reservoir.
I filled the reservoir to the top of the bulkhead fitting and made sure there were no leaks. Next, I put in a 1-inch layer of 3/4-inch river rock before I laid in the fill tube. Once the fill tube was in place, I continued to fill the reservoir with rock to the top of the lower 2×12.
After the rock was in place and leveled, I covered it with a sheet of shade cloth to prevent the planting medium from seeping down into the reservoir. I filled the bed with moistened potting mix to a depth of about 10 inches. After filling with this planting medium, I attached furring strip inside the of the bed and trimmed off the excess liner. This was to hold the liner firmly in place. The finishing touch was a 3-inch border along the top.
Wicking beds work on the principle of capillary action from the water. Water molecules are attracted to other molecules and can move vertically almost 12 inches. There is also some evaporation/condensation in action in the bed. Even though I was impressed with the wicking garden bed concept, I looked at the pros and cons before making the decision to build two for my yard.
Pros:
- The bed is 2-feet high making gardening easier.
- The constant supply of moisture at the root level and overflow tube prevent over-watering.
- The bed is drier at the surface so weeds cannot germinate.
- Use 40-50% less water
- I can leave for a couple of weeks without worry because I water less often.
- Can be constructed on any surface
- Minimal loss of soil amendments because they are not being washed away by top watering
- Salt and minerals are not added to the planting medium from top watering
- Difficult for tree roots and grass to penetrate the liner
- I am growing nutrient rich food for my family.
Cons:
- More difficult to construct than a traditional raised bed with less parts
- More expensive than traditional raised bed
- Some change in the way you maintain your raised bed
- Requirement to drain and refill twice a year.
UPDATE: Here is what his two wicking garden beds look like at the beginning of May 2017. The one in the back has a cage of PVC frame with plastic chicken wire to keep the birds and squirrels out of his six varieties of tomatoes, as well as the parsley, kale, and celery. The one in the front is producing abundantly with zucchini, I’itoi onions, cucumbers, melons, two varieties of green beans and an okra plant.
Want to learn more about Raymond or wicking beds?
He was our featured farmer for April 2017!
Read our Q&A with him here.
Listen to Raymond on The Urban Farm Podcast
Wicking Bed Articles:
Building my wicking garden bed (Wicking bed 1.0)
Wicking Bed 2.0
Wicking Bed 3.0
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How often would you have to replace the soil?
Ray says you don’t have to replace the soil if you keep up with green gardening practices and replenish the nutrients with minerals, compost and worm castings.
When he says “beds should be drained and refilled twice a year,” does he mean just the water or the soil as well?
Because of the hard water here in the Phoenix area, the salts and hard minerals build up in the water reservoir. The soil only takes up “pure” water without the minerals. That leaves behind an opportunity for the build-up of those salts and minerals. I generally purge mine in late January and again in late June. The soil should not have to be replaced because hopefully, you are feeding it what it needs to stay healthy and full of life.
I build some in the ground with a liner, drain field pipe which is 3 or 4 inches in diameter. carpet padding as a separator over the pipe and sand on top of that then garden soil and compost. A drinking water bottle with a flag on top as a waterlevel indicator in the upright fill tube. For above ground beds I use a half of a plastic barrel with the same arrangement. The half barrels can easily be moved to new locations for the right microclimate as the seasons progress $25 barrel makes 2 planters $10 for corrugated drain pipe for 2 planters. Used carpet padding freee. If the planter will be in the rain drill holes half way up for drainage. If nessesary water can be removed with a siphon hose.
I love your idea of rain barrels. I have been using round totes with handles that I found at Walmart. I wanted to make more, but I cannot seem to find the totes. I have 8 tote/wicking beds made like yours.
I love the idea different construction methods are being shared. I too have used totes as a wicking bed garden as well as global buckets. My hope is more readers will share their ideas, successes and learning experiences.
It would be great to know:
– The specific brand and dimensions of the pond liner, and the specific part he used for the bulkhead fitting.
– How did he penetrate the liner to facilitate draining via the bulkhead? Did he seal it? If so, with what?
Thank you!
Hi Aaron,
The best deal I found on the web for the pond liner was from Billboard Tarps (link follows), the dimensions would be specific to the bed you are planning. I knew I was going to built two beds so I ordered accordingly.
https://billboardtarps.com/product-category/new-vinyl/new-vinyl-20-oz/
I purchased the bulkhead fittings from a local pluming supply store, making sure the length of the barrel would accommodate the thickness of the wood. I used a knife to make a hole large enough for the barrel of the bulkhead fitting. Bulkhead fittings come with a rubber gasket and a nut which provide an excellent seal.
I am in the process of building a wicking bed using a horse trough. Instead of river rock I wanted to re-use old plastic water bottles along with pool noodles and place them in the water reservoir. Would that work or would the pool noodles prevent wicking?
Hi Jackie, Just a quick note from us here at the Urban Farm. We love and encourage repurposing and recycling! However, we recommend you do some research on the plastics used in the bottles and in the pool noodles. It is my experience that the pool noodles do not hold up under the rays of the sun or just regular weather (any that my boys left outside were toast in one swim season), so I am not sure how long they would last in the trough, and they will not like to be submerged. Then for the bottles, many thin plastics present issues with breaking down or becoming brittle in the sun, and some have issues with bacteria. There are several articles and videos about the code on the bottom of plastic containers that could answer that for you. Congratulations on trying to think outside the box though! Keep up the good work. We would love to see pictures!
Hi Jackie,
I love the idea of repurposing an old horse trough. The only experience I have with pool noodles is in the pool with the grandchildren. If I were thinking about using pool noodles, I would check the manufacturer site for the chemicals used to make them and the decomposition rate. My experience with water bottles is they get a build-up of bacteria over time and leave a terrible taste in the water. I suggest you do some more research on what would make a good medium for a reservoir. Collin Austin is an excellent resource: http://www.waterright.com.au/TypesOfWickingBeds.pdf
Please let us know what you decide.
The resolution on the photos is such that I can’t see the details in most.
Hi Ruby,
This photo was taken on my cell phone so this is the best resolution I have. Is there anything specific you wanted to know about what was growing at the time aside from the description in the paragraph above the photo?
Ray
Hello,
I am in the process of constructing my wicking garden bed. I have three 4′ X 2′ raised garden beds made of cedar. I have the pond liner, small river rocks and shade cloth. I looked online for the Bend A Drain, as they did not carry it at Home Depot, and all I saw was the perforated. is that the correct one? Bend-A-Drain 4 in. x 25 ft. Polypropylene Flexible Perforated Pipe with Sock
(18).
Also, can you please explain more about the overflow valve? Does it go through the pond liner?
Thank you so much for your time.
Tara
Hi Tara,
This is the link for the perforated drain pipe I used. I believe you can order it on line and pick it up at your local Home Depot.
https://www.homedepot.com/p/Bend-A-Drain-4-in-x-25-ft-Polypropylene-Flexible-Perforated-Pipe-330125/205313163
I did not spend the extra money for the one with the sock. You will be flushing out the drain and the bed twice a year anyway. I have not experienced any issue with debris in the tube in the four years I have had my wicking beds.
For the overflow, the bulkhead fitting goes through both the frame of the bed and the pond liner. It doesn’t matter which direction you put the bulkhead fitting in as long as the rubber gasket is on the inside of the pond liner. If you are concerned about the fitting not sealing, you can apply some sealant around the fitting and the pond liner.
I hope this addresses your questions and concerns and please feel free to share photos of what your bed turns out to be.