If you're interested in gardening with self watering containers, but still want to make use of your existing standard planters, here's a great way to convert all your planters into self watering containers. This project would also be good for gardeners interested in growing in self watering containers, but want something more visually attractive than storage totes.
To convert a standard planter into a self watering container you'll need a watertight container with a lid, this will act as the water reservoir, a tall water bottle, this will act as the fill tube, and 2 strips of fabric, these strips will draw water from the reservoir to the soil above.
Try to find a container that matches your planter in shape and width. I lucked out and found a bowl that just fit into a 16" diameter pot.
Mark the lid of the container with 1 large hole for the fill tube, 4 slits for the fabric strips, and a bunch of small holes for soil aeration.
Also, don't forget to add an overflow hole near the top edge of the water reservoir. If you will be placing this planter on an uneven surface it's best to drill holes on all sides of the reservoir to ensure proper drainage.
I used an electric drill to make the holes, but the plastic was soft enough that a sharp knife and elbow grease would have worked just as well.
Insert the spout of the water bottle into its hole on the lid and insert the fabric strips into the slits. Make sure the fabric strips are long enough to reach the bottom of the water reservoir.
Special Note: If you use 100% cotton for the fabric strips they will eventually biodegrade and will need to be replaced at the end of the growing season. Poly cotton blends or all synthetic fabric strips will last longer.
If you're going to add a cage to the planter add it before you add the soil. Have the spokes of the cage pass through the air holes of the reservoir so that the cage rests at the bottom of the planter. A cage that rests at the bottom of a planter will be much more stable than a cage that sits in only the top half of the planter.
Top water the soil after it's added to the planter, then use the fill tube to fill the water reservoir. You can tell the water reservoir is full when water starts draining from the bottom of the planter. Add a tray to the bottom of the planter if it's staying indoors to catch the excess water.
If you like this idea, but aren't interested in doing it yourself, you can buy a pre-made version at gardeners.com. I bought a few of these for the roof the first year I started gardening, before I discovered the fun of diy projects.
16" Planter: $7.62
Plastic Bowl with Lid: $2.18
Running Total: $123.75