Self-watering containers benefit both you and your plants. Self-watering containers encourage a plant's roots to grow downward, toward the water supply. This keeps the roots from growing upward or in a circular patterns, choking out the plant. Self-watering containers also keep soil consistently moist, but not wet, which is the ideal soil condition for most plants. In terms of convenience, self-watering planters allow you to water less, which is especially nice for plants in hard-to-reach places. There are several different types of self-watering planters, but they all work on the same principal. For a simple self-watering planter, purchase two decorative plastic containers--one that fits inside the first planter with 2 to 3 inches of extra space between the planters. The large, outer container should not have drainage holes, but the inner container must have holes.
Heat up the soldering iron. Do not add any special tips to the iron. Measure 1/2 inch from the bottom of the small container and use the solderer to melt a small hole in the plastic. Poke through and remove the solderer quickly for best results. It should look like a hole on the side of a sheet of notebook paper.
Measure about 1 inch to the right and poke another hole. Continue melting holes in the plastic until you've made it all the way around the planter.
Measure 1/2 inch above the row of holes you've made and create another row of holes using the same technique. Alternate this row so the holes are above the inch of blank space that separates the holes on the bottom row. Repeat this step a third time so you've created three rows of holes along the bottom of the plastic inner planter.
Place two terra cotta plant saucers in the bottom of your large planter. These saucers help keep the inner planter elevated so the plants can draw moisture up from the bottom drainage holes as well.
Thread a watering wick through one of the bottom drainage holes. Pull half of the wick through the hole and leave the other half in the container. Thread a watering wick through one of the side holes you created so half of it remains in the container and half extends out of the container. Repeat on the opposite side of the planter so that you have a total of three wicks (one through the bottom and two through the sides). Wicks mimic plant roots so that new plants whose roots aren't yet long and strong won't risk not getting enough water.
Place the smaller planter inside the larger planter, on top of the saucers. Test to make sure the saucers don't block the drainage holes. Move the planter to its intended location.
Gather the wicks inside the container in your hands and lift them up as you fill the container with soil. The idea is for the wicks to extend into the soil, so they can help draw water upward. Let go of the wicks when the container is half full of soil. Fill with more soil, burying the wicks.
Fill the the spaces between the large planter and the small planter with water. The plants and the wicks will use a process called capillary action to draw water into the soil through the drainage holes as they need it. Check the planter regularly to make sure it hasn't dried out.