There are other benefits to growing vegetables in self watering containers: you conserve water by only watering the plant and not the surrounding sidewalk or patio with the sprinkler (or is that just me?) and may be less likely to kill the plant if you forget to water it every day (also me.)
I built the Mark 2 in the Earthbox style (learn more about it here) with a plastic aeration screen making a false bottom to fill with water. Unfortunately the aeration screen collapsed during the winter under the weight of snow and heavy wet soil. (Disclosure: I am including affiliate links in this post for your convenience.)
There is another style of self wicking planter that creates the water chamber with gravel and allows the water to wick to the plant roots using a layer of landscaping fabric as a wick. Both water conserving planter ideas work well but I want to to reduce potential spring maintenance of replacing aeration screens that collapse under weight of wet soil or decomposing cloth wicks on a yearly basis.
I combined the two styles to make self wicking and watering tomato planters from pretty flower pots for my container garden.
Since I have to look at my planters on my patio day in and day out (and so do my neighbors,) I built my self watering tomato buckets out of resin planters instead of 5 gallon plastic buckets.
As always, your mileage may vary.
You will need the following to make this project:
1 1/4 inch PVC pipe
1 1/4 inch PVC cap
1 1/4 inch PVC elbow
1-1/2" Threaded hub female adapter
1/ 1/2" Threaded hub male adapter
5 inch Porous terra cotta flower pot
Drill and drill bits
Window screen or weed barrier landscape fabric (it looks like this)
Step by Step How to Make It Tutorial:
1. On the outside of the flower pot, measure the height of the clay flower pot, add ¼ inch, and use the drill to drill a water overflow hole in the side of the container at that measurement.
Optional: I cut and glued a small piece of window screen over the over flow hole to discourage mosquitoes from using my big pool of still water as a nursery.
2. Measure the height and width of the large flower pot and cut the PVC pipe with the saw to the height of the plastic tub plus several inches to make the watering tube and width of the flower pot minus a few inches to make room for the elbow joint and plastic end cap.
Tip: Some home improvement stores will cut PVC pipe for you. Even better if you can find a store that lets you order it online and pick it up already cut to your dimensions at your local store.
3. Use the drill and drill bit to carefully drill a series of holes in the shorter PVC pipe.
I find it easiest to clamp the pipe to my workbench and drill a line of watering holes down four side of the PVC pipe.
4. Use the PVC cement to glue the PVC pipes, caps, and elbows into place.
The hubs keep bugs and debris from entering the water reservoir uninvited.
5. Put the watering tube and the clay flower pot in the large flower pot. Wrapping the watering tube with a piece of window screen or landscaping fabric is a good idea. It will discourage the pea gravel and dirt from clogging the holes in the watering pipe.
6. Fill the terra cotta flower pot with soil and put it beside the watering tube in the bottom of the large planter pot. The clay flower pot will be our wicking chamber with the added bonus of not needing to line it with weed barrier to keep the potting soil from leaching out unlike plastic flower pot wicks.
7. Fill the bottom of the self wicking planter pot with pea gravel until the level reaches the drainage hole you drilled into the side of the planter.
Caution: Be careful not to fill the terra cotta wicking pot with pea gravel!
8. Fill the rest of the planter with potting soil and soil amendments if desired.
9. Plant your seeds, water them by removing the twist cap on the watering tube, and watch them grow!
The clay pot is porous enough to draw water from water reservoir and into the dirt in the wicking pot. The soil in the wicking pot acts as the wick the layer of potting soil will use to draw water up from the water reservoir and to the plant’s roots. Science baby! Ain’t it cool?
This is a quick and easy project. In fact, the most difficult part of this project may be trying to find a large non porous flower pot with out a drainage hole drilled into the bottom.
I busted out five of these bad boys and converted the Mark 2 self watering planter box from a plastic storage tub into a self wicking planter box (now christened The Mark 3.) in a few hours after coming home from the gardening center with a carload of vegetable plants.
If you'd rather buy than DIY, check out the following ideas - and more! - below!