YouTube is such an amazing tool to explore new ways of growing food. I happened upon a farmer from Oklahoma named Leon who created the self-wicking tub. Unlike a traditional container with holes on the bottom for the water to drain, this one actually sealed on the bottom and the hole is on the side.
This allows there to be a few inches of water to give the plants access to water throughout the day instead of having it drain out the bottom. This also means you can water the plants less frequently and using less water because the container retains water.
The secret is creating a 1-2 inch air buffer above the hole on the side. This allows for the plants to not become water logged and die. Instead the soil can wick the water up to the plant roots because of the air pocket.
My unique take on Leon's method is that I actually want to grow veggies inside because I can control the environment better and keep them sheltered from Denver's extreme weather (heat, cold, wind, hail, etc.). But I also want surface area to grow a decent amount of veggies. Leon's animal feed containers are certainly way too big but a 5-gallon bucket is too small. The solution? Those ubiquitous black storage bins with yellow lids that can be found in Home Depot and Costco. My preferred size is the 17-gallon verions.
Here are the steps to creating the tub (along with pictures below):
Materials and Tools
- 17-gallon storage bin with lid. Make sure it is no translucent as that could cause algae to form in the soil and water.
- 1.5 cu. ft. organic potting mix. Potting mix is important so the soil stays light and aerated.
- Drill with 1/4 drill bit for hole on the side.
- 18 inch length of 1" PVC pipe with one end cut at a 45 degree angle (I use a hand saw miter box to cut the angle).
- Empty soda cans or water bottles with lids. 40 cans or bottles fit the Home Depot 17-gallon bin. You made need to adjust the quantity for your bin.
- Ice pick for poking holes in the cans or bottles.
- Put the bin on a flat surface and measure 3.25 inches up from the outside wall. Drill a hole using the 1/4 inch drill bit. Ideally put the hole towards an end side, maybe like 4-5 inches away from the end.
- Put a can or water bottle inside the bin near the hole and ensure the whole is at least 1 inch below the top of the can or water bottle. This is what will create the air pocket.
- Using the ice pick, begin to poke two holes in each can or bottle. One an inch from the bottom and another about where the bin side hole is. Note, if you are using cans, you will actually be tipping the can upside down so the bottom of the can becomes the top. This allows the water to fill from the bottom while maintaining that air pocket at the top. If using water bottles, make sure the lids are on tight to ensure an air pocket can form.
- Arrange the cans or bottles at the bottom of the bin and try to space evenly as best you can leaving just a bit of space around each can or bottle for the soil to reach the bottom of the bin.
- Add the PVC pipe with the angle going down in the bin so water can flow out. The angle allows the water to come out of the bottom easier. I put the PVC pipe on the opposite end of the hole so the water has to flow to the other side of the bin before coming out of the hole.
- Now pour a bit of soil into the bin and spread it around as evenly as possible moving into down between the cans or bottles. Don't life the cans or bottles because the soil will just take its place. Just shift any cans or bottles by moving them sideways.
- Add more soil to cover the cans or bottles and again spread it around to ensure the soil goes between the cracks. Then add more soil and pack it down lightly and evenly. Then add the rest of the soil leaving 0.5-1 inch of space at the top of the bin.
- You can now move the bin to its final resting place. Be sure to do this while the soil is dry because it'll become too heavy once filled with water.
- I put the lid under the bin to catch any water that comes out of the hole. And I have it setup in my kitchen bay window under a stool. This puts it at a comfortable height and I can check on it daily to add water and harvest food.
- Add 2-3 gallons of water through the PVC pipe and stop if water becomes to drip out of the side hole. I like to add hydroponic nutrients to the water so the plants have proper food to grow healthy. The soil will have some but it likely won't be enough for the plant's entire life.
- Water the top using a watering can that can spread the water evenly across the surface of the soil. Now you are ready to plant the seeds or starter plants. Be sure to know the proper spacing and plan accordingly. And favor quick vegetables with shallow roots like lettuce, spinach, beats, carrots, cabbage, radishes, etc. The bigger plants like zucchini, peppers, eggplant, and tomatoes might be better outside or in their own 5-gallon bucket container.