How Do Self Watering Planters Work?

In many cases, self watering planters and containers are very beneficial especially if you live in a dry zone or are prone to forget to do the watering of the garden. The way self-watering containers work is that there is a reservoir at the bottom of the container that holds enough water for a long period of time.

The plant receives water from the reservoir through a channel of soil that works as a wicking agent pulling the water up through capillary action.

How Does It Work?

The bottom of the container is a large plastic reservoir that is filled with water. The top of this reservoir is solid plastic with drain holes that allow excess water to drain from the soil. On the side are drain holes so that if the reservoir is over-filled, the excess water will drain out. There is always a danger that too much water will get into the reservoir and overwater the plants unless there is a drain mechanism.

Misco Self Watering Planter.

This Misco self watering planter above is very reasonably priced and will get you started quickly and easily.

When the soil starts to dry out, the water in the reservoir wicks up through the soil and begins to hydrate it. Many self-watering planters can go two to three weeks without having the reservoir filled depending on the type of plant, humidity in the area and the size of the plant in the container.

Plants Suited for Self-Watering Containers.

Most flowers, both annuals and perennials, work well in a self-watering container as do many vegetables. Herbs are well-suited for self-watering containers as well. Try lettuce, bush beans, cucumbers with a trellis attached to the container and any other vegetable that grows above the ground. Root vegetables usually need deeper soil conditions than a self-watering container can provide.

A good starter self watering container.

This self watering container pictured above is also very reasonable and has very good reviews.

Also plant basil, rosemary, thyme, savory, parsley and any other small herb in a self-watering container. Dill grows very tall and may not be suited. Those plants that need soggy conditions to grow are not suited for this type of container because the soil never gets over-wet.

Salt Concentration on Containers.

Salt may collect in the potting mix only because the water comes up through the soil and evaporates from the top. Salt is often left behind and this can be detrimental to the plants in the container over a period of time. The only water that does not contain salt is distilled water and most plants need other minerals in regular water, so using distilled water is not a good idea.

Commercial fertilizers also contain salts that get into the soil and have nowhere else to go because the soil is confined to the container. Avoid using liquid fertilizers or those that have time-release ability. Instead, use a granular fertilizer worked into the soil and NOT in the water reservoir. This will help keep the salt content down.

Another way to avoid salt deposits is to use compost in the potting mix to give the plants better nutrition and less salt. Every once in a while (2 to 3 times per summer) run water into the reservoir until it starts coming out the drain hole on the side. Keep it going for a few minutes to flush out any old water that has been sitting there for a long time gathering salt.

Other Maintenance.

Since the soil is contained in a container, it is best to get rid of the soil every other year and replace it with new growing medium. This will keep the soil healthy and full of nutrients. Mix the soil with compost to keep it healthy.

When you first set up your self-watering planter, you will have to place water in the reservoir through the hole or tube where you can hook up a hose. Then, water a bit on the surface of the soil so that the capillary action will be activated. If you don’t, the soil in the bottom will not start wicking up from the reservoir. It needs a little jump start to get it going. Those that live in a cold region must always bring in self-watering pots in the winter.

If the water freezes in the reservoir, it expands and can crack the reservoir. Drain the self-watering planter and invert it in storage over the winter. Self-watering containers are great for those that like to have things growing on their porch or deck during the summer, but often go on extended vacations. These people do not have to find someone to water their plants for them while they are gone.

The self-watering containers do it all by themselves. They are also a great thing for those that tend to forget to water their plants frequently. Generally, the self-watering planter only has to be filled once a week to two weeks under normal summer conditions. Just go out and fill the reservoir every Sunday and you are ready to go the rest of the week without worrying if your plants are getting enough water.