DIY Wicking Tubs with Wood Chips?

[gtaus]

I have been watching some YouTube videos by Gardening with Leon, and he makes wicking tubs for growing vegetables and fruit trees. He fills the bottom of his tubs with plastic containers to create a water reservoir. Basically, he drills an overflow hole in the tub about 1 inch below the top of the containers he puts into the tub. This 1 inch gap between the water reservoir and the top of the container ensures an air gap so the plants' roots are not drowned in sitting water. I understand this concept and have previously built a very successful elevated 2X4 foot sub-irrigated planter (SIP) that I have out on our deck. I grow more beans in that SIP planter than in the garden using 4 times as much space. So I am interested in making some wicking tubs this year because they would be much easier to move than my elevated planter.

My question, is it possible to use wood chips in the bottom of the tubs instead of plastic containers? I am thinking that 6 inches of wood chips in the tub, with an overflow hole drilled into the side of the tub at 5 inches, might accomplish the same task as using plastic containers. But maybe not. Would the wood chips in the bottom of the tub steal the nitrogen needed for the plants growing above it? If so, can you just add some nitrogen fertilizer into the potting mix to offset this problem?

I have lots of free wood chips, and I just think a tub of wood chips and potting soil sounds better than a tub of plastic milk jugs and potting soil. Having said that, I am more interested in actual results. If anyone has tried using wood chips in a wicking tub, I'd love to hear how it worked for you. Thanks.

There are many Gardening with Leon videos on YouTube, but here is one to check out on his wicking tub concept.

 

[cavemanrich]

I container grow many flowers and other plants each summer. My containers are LARGE. I do not fill them totally with soil. I place a few bricks on bottom, and on top of these, I fit a piece of wood. (usually last chance plywood) I drill holes in plywood to allow for good drainage. I water my flowers daily, and like the results I get. My soil layer is from 5 to 9 inches thick, depending on which pot. I also mix my own soil mixture. Potting soil, peat moss, garden topsoil, and sand.
I can get all the wood chips I want also. (free) and do use these in my chicken run area, as well as portions of garden for walkways. I also use those wood chips in backyard areas, where I do not want weeds to grow, like behind the shed.
I would not use wood chips in my container pots for the following reason.
The wood chips will start to decompose. Since they would be at bottom of container, and covered with water, it would be an anaerobic decomposition. (very little to no Oxygen) I'm not a fan of such composting. Here is a quick copy and paste that explains my point.

Since Anaerobic Composting occurs in a sealed oxygen free environment or underwater, decomposition of the organic materials can lead to very unpleasant odours due to the release of sulphur containing compounds such as hydrogen sulphide, but these slight sulphur odours can indicate that the decomposition process is working properly.

One of the main disadvantages of anaerobic composting is that if the compost is not allowed adequate time (at least one year) to ferment and breakdown the biomass feedstock, there is a risk that the compost will contain harmful pathogens because there is not enough heat generated in an anaerobic pile and the decomposition process relies only on the microbes. Given enough time to breakdown the feedstock, any pathogens that may have been present will eventually be out competed by more beneficial micro-organisms.

I highlighted in RED my main concerns..
Pix below shows some of my containers. Only the larger ones are those that I place bricks, and plywood spacer into. If those were filled totally with soil,,,, It would take A MAN AND A BOY TO MOVE meaning they would be HEAVY.

I'm just an amateur gardener, and learning new things always.
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 

[gtaus]

@cavemanrich Thank you for the informative reply. You brought up a very point that I had not considered in the Anaerobic Composting of the wood chips sitting in the pool of water at the bottom of the self wicking tub. I will be using some 18 gallon muck tubs for my wicking tubs. So there might be as much as 5 gallons of water sitting in the bottom 5 inches of the tub. If that was filled with decomposing wood chips, I think you might be right on the smell and other adverse events I would create.

I did see some YouTube videos where people made HugelKulture pots that had wood chips in the bottom 1/3 of the pot, but they also had drain holes in the bottom of the pot so there would never be a pool of water - like I am going to build with the wicking tubs. The HugelKulture pots might be option for some planters I have laying around. But I think you are right in that it's probably not a good idea in a wicking tub with a large pool of sitting water at the bottom.

FYI, the elevated 2x4 foot SIP planter I made for my deck uses 4 inch corrugated drain pipes in the bottom of the planter. The bottom of the planter is lined with a pond liner up about 8 inches on the sides which are 16.5 inches tall. I have an overflow tube cut into the planter at about 3 inches, so that always leaves a 1 inch gas between the sitting water and the top of the drain pipes. I use potting mix to fill the planter. Anyway, a pool of water 3" X 2' X 4" is almost 15 gallons. I think I only had to refill that planter 3 times all last summer. I grew more beans in that planter than I could have imagined. I am not much of a gardener (yet), but I sure had success with the SIP planter. Only problem is that is too heavy to move once the water and potting mix are filled in the planter. I hope that my 18 gallon tubs will be easier to move, even if I can use a dolly it would be OK.

 

[gtaus]

@cavemanrich I found another YouTube video where the guy used wood chips on the bottom of his self wicking tub, then a layer of greens for nitrogen, then about 12 inches of compost/potting soil. He reports that his plants did very well in that pot. As to anaerobic composting in the bottom water layer, yes, but you can't smell it given 12 inches of soil above that layer and the drain hole is only about 1/2 round. There was a comment on the video that the anaerobic composting in the bottom of the tub would poison the plants above, but this guy reported that the 12 inches of soil above the water layer prevented this from happening.

So, I plan on making at least one self wicking tub with wood chips (aka Hugel pots) and experimenting with it this summer. Thinking ahead, I'll put the drain hole in the tub at 3 inches so if the wood chip design fails, I can go back to using my 4 inch plastic drain pipes in the bottom which I know works. I bought a number of those 18 gallon round tubs this winter when they went on sale, so I should be able to set up some good experimental tubs for comparison.

Anyway, here is the YouTube video on Hugel self wicking tubs....