My latest SWC prototype
My newest SWC with Sungold planted is very experimental, so please keep that in mind:
It's an 18 gallon Rubbermaid tote with a soil bench made from a 14 gallon tote. What makes it different is the PVC pipe framework inside. The PVC structure combines the fill tube, soil bench support, cage support, and reservoir shutoff valve:
- The shutoff valve is just a CPVC valve with the knob removed and a piece of 1/2" copper pipe with 1/2" to 3/8" coupling slipped over the stem and screwed. The valve is really easy to turn with just the copper pipe, I don't think a handle on top is needed, although I may cap it to keep skeeters out.
- The wicks are from rayon mop and sit down inside the PVC frame uprights.
- The fill tube is part of the frame so that any dirt gets flushed from the valve whenever the reservoir is filled.
I used 3/4" PVC for the frame with a 1" for the fill tube to make it easier to fill:
- The soil bench is supported in the middle on the shoulders of the PVC T fittings.
- There is a single wick in the center as a fail safe to allow the bottom 3/4" of water to be accessible to the plant (the valve opening sits about 3/4" from the bottom). I'm going to try drilling a hole through the middle of the valve seat to circumvent this issue.
- The large aeration holes are based upon some of my wicking experiments this past winter. I noticed that landscape fabric against small holes in plastic really restricts drainage, and this design needs the landscape fabric or soil could work down the sides of the bench and wick additional water.
- A tomato cage slips down inside the top caps of the PVC frame. This transfers the load to the ground instead of the soil bench, and makes bot setting up and end of season cleanup much easier.
I hot glued a small piece of insect screen over the drain hole to keep skeeters out. (Last year, I tried landscape fabric over a drain hole and it was a disaster):
It took longer to build than I expected, especially gluing up the PVC frame. I may try one that's just press fit since it's not under pressure.
I'm uncertain if 5 wicks will be sufficient, but it would be easy to add more if needed. I also don't know if the valve will be capable of regulating moisture, or will only work as an on/off switch for the 4 wicks.
I will be adding a fertilizer strip and plastic mulch cover in a few days. The reservoir is also empty right now. I've been having better results by letting the mix drain and settle a bit after setting up rather than starting with a full reservoir.
I'm not recommending anyone try this, it's unproven, possibly silly, and a solid indication that I've officially lost my mind.