Wicking Bed Construction
After researching different gardening options for dry climates, I decided to try a wicking bed in a portion of one of my raised bed planters. I am planning to collect rainwater in buckets and fill my wicking beds with the collected water. The size of the water reservoirs was limited by the size of the existing raised bed and the PVC pipe installed below that supplies water to the remainder of my garden. I chose to use plastic tubs that I purchased at Lowe’s.
I used 1” PVC pipe and cut the pieces to fit in the bottom of the plastic tub. It is not necessary to glue the fittings except for the riser pipe that is used to fill the beds with water. The remainder of the fittings can just be a pressure fit.
I drilled holes in the bottom of the PVC pipe to allow for even flow of the water into the reservoir. The holes are only drilled into the bottom to prevent roots from growing into the pipe.
I used a 7/8” hole saw to drill holes just under the rim of the tub to insert a length of ½” PVC with holes drilled in it to act as an overflow pipe. This drainage pipe will have the holes in the pipe level with the surface of the pea pebbles to allow for drainage if the water reservoir is too full. The riser pipe is painted to protect it from UV damage from the sun. Prepare the area where the wicking bed will be by either digging down or building a raised bed to accommodate the water reservoir and the garden bed above it. Since this is a vegetable garden planted with seasonal plants, I allowed for planting soil and mulch levels to be 8 – 10 inches above the water reservoir. If I were planting perennials, I would allow for a deeper reservoir and deeper planting beds to accommodate the deeper root growth.
This is the raised bed that is prepared for the wicking bed. Notice that the size of my tubs was restricted by the plumbing that was already in place for my existing garden.
This is the placement of the two water reservoirs in my raised bed.
It is very important to make sure the tubs are level before filling with pea pebbles.
After the tubs are filled with pea pebbles, fill them with water to make sure the overflow drain is working properly
Back fill with some of the pea pebbles around the base of the water reservoirs.
Cover water reservoirs with weed cloth to prevent soil from getting into the pea pebbles.
Backfill with soil up to the level of the rim of the water reservoirs.
Amend the soil that is going to be your planting bed. You can use any brand planting soil that you like. I prefer a planting mix with high organic content. I mixed 35% existing soil with 35% Planting Soil, 20% Vermiculite, and 10% Perlite.
Then I put planting pots (with the bottoms cut out) around the bubbler risers in the pre-existing part of the raised bed. This was a step to keep water from running out of the planter when the bubblers come on and prevent flow into the water reservoirs. I could have just lined the planter in the back with plastic, but I rather like my “Rainbow Pots.”
Cover the amended soil with composted mulch.
Now the planting bed is ready to plant!
I planted my vegetables and tubers and then put a layer of weed cloth around them. Then I covered the weed cloth with colored mulch to not only hold in the moisture, but to make it attractive.
I finished the garden by putting down weed cloth and pea pebbles between my raised beds.