Plastic-free wicking bed?

Hi ya'll,

Has anyone attempted a plastic-free wicking bed? I see one post mentioning using a clay lining instead of sheet plastic Inground Clay-lined Hugelkultur Wicking Beds but that is all. I live in Central TX, where we are in a continuing drought and wicking beds have a lot of success here. BUT, I don't want to risk the nasties of PVC and other plastics as they break down. I grow our food in part to limit our exposure to crazy toxins.

So, my idea is to do something similar to the clay-lined hugel outlined in the link, but do it in a traditional raised garden box. Wicking beds usually have plastic all the way up the sides though - will it lose too much water without that? Also, wicking beds usually have PVC pipe running under them to distribute the water. Would a terracotta pot olla without the bottom sealed work as that pipe? Or is there appropriate (and affordable) metal piping that can be used?

Any ideas / input are appreciated. My hope is to build some kind of water efficient bed come late January.

Thanks,
Alexis

Clay lined wicking beds work well.
The clay does the same thing as the plastic liner material, keeps the water in the bed and not in the deep ground.
I would use clay in the same manner, bottom and up the sides.

Terracotta pots have been used for distributing water for at least 800 years, the Aztec, Maya, Apache, Inca, Anasazi, Hopi, Navajo cultures all used this method with great success.
Instead of removing the bottom I would just drill holes around the bottom to disperse the water, it will spread it out better than just a jug minus the bottom, this will help in keeping water use down to a bare minimum.

Thanks for the response! I hadn't thought about drilling holes in the pots, but it makes sense. What kind of drill bit would you use? Also, would you add a gravel layer on top of the clay to act as a reservoir or can you just do soil?

I like to use a masonry bit and go very slow on drill speed. I also make sure the pottery is wetted before I start, this keeps chipping to a bare minimum. I've never added gravel to one,

So I finally got my clay lined bed built! It's 4'x4'x16" deep, made of cedar boards. I used a 50/50 bentonite clay and topsoil mixture 2" deep for the bottom. There are two homemade terra cotta ollas a foot from each side with holes drilled in the bottom (thanks for the head's up about the masonry bit). I used a standard square foot garden mix of 30% each of compost, vermiculite, and coir as well as rock dust and eanthworm castings. It planted it the day after completion and seeds are germinating well and the transplants look very happy.

Here's the clay lining (while I was struggling to get it level) -



Here's what it looked like pre-planting -



There are pictures of each step on my blog - Bean & Bee - Clay Lined Bed
So far everyone thinks it's kind of a weird idea. I appreciate the input I got here and I will post an update in a few months.

Did you really NEED raised beds? It occurs to me that the wood is likely to wick away moisture to the outside and evaporate it, whereas a clay-lined in-ground bed might not have that problem.

I actually do. I'm in the Edwards Plateau region of Texas, which means we have a few inches of contractor grade fill dirt over limestone rock. I don't know anyone around here that grows directly in the ground, at least not for kitchen-garden type vegetables (which is what will be this bed). The wood wicking may very well be an issue. I went back and forth about painting the clay onto the sides as well but decided against it because then I would have to drill overflow holes into the boards. Since this is an experiment, I wanted to keep the box in a traditional raised bed condition so I could convert it back to normal is the clay liner seemed to be a problem.

I haven't watered this bed since April 9th. Here's what it is looking like today. We have had a nice and rainy spring for once, but I think the clay is making the water last longer.





It's all pretty much traditional kitchen garden plants - tomatoes, zucchini, cucumber, carrots, basil, melons, cilantro, and purslane. July will be the true test of this system, but I am happy with it so far.

Any updates?

Hi there, very belated update for you! I expanded the bed to 4 x 8 feet and used clay on the expansion as well. The terra cotta pot "ollas" filled with ants, so I ditched those and switched to regular drip irrigation. The clay works well keeping tree roots from growing into the bed and holding water. I just built another 4 x 8 bed lined with clay today, doubling my growing space

I also found that kitty litter is often just bentonite clay - way cheaper and easier to find than the powdered stuff I used for the first bed.

Hello, I'm interested in making a clay-lined wicking bed.  How did your raised bed work out?  Any updates?

Thanks in advance!