How Do Self Watering Planters Work? Watering Has Become Less Of A Chore

How Do Self Watering Planters Work?

Your plants need optimal hydration to survive and grow - that is why watering is one of the most important tasks around the garden. At the same time, it is one of the least favorite chores, as it takes a lot of your time and energy. For example, a container garden has to be watered up to three times a day during the hot summer months with no rain in sight.

Fortunately, for all you container gardeners out there, an easy solution to the watering problem exists. Self-watering planters provide consistent moisture to your plants and reduce watering to once or twice a week.

In the beginning, self-watering planters were made up of a simple outer pot that held water and an inner pot that held soil and plant, joined by a wick. Recently, a new generation of these planters was introduced - they have a separate water reservoir, specially designed to ensure that the plant roots are protected from the excess moisture and mold.

The hollow reservoir is usually made out of solid plastic material with one or more holes on top of it. It is attached to the bottom of the pot, from where it uses “capillary action” to hydrate the plant. Most self-watering planters are equipped with an overflow hose to drain excess water from the surface and prevent standing water above the soil, which is capable of damaging and drowning your plants. This way, your plants get enough moisture without you having to water them daily. A more in-depth explanation about how self-watering planters work will be explained further below.

How Self-Watering Planters Work

The design of self-watering planters is rather simple, but it is without a doubt very efficient. Most self-watering planters are based on the same principle, which is capillary action or wicking. For example, dipping a piece of paper in water will result in water climbing the paper. Soil works in a similar way and it draws water up as the plants take the right amount of water that it needs to grow.

This principle is the key that makes self-watering planters so efficient, especially compared to the older versions of self-watering planters. With the newest generation of this planter, plants do not absorb too much moisture. On the contrary, they absorb as much as they need and as previously mentioned, you no longer have to water your plants daily. This is also a more natural and better way to water plants, rather than pouring water on top of them. This is because the roots of the plants will be able to control how much water to take in.

What basically self-watering planters consist of are two containers in one. The lower container serves as a reservoir and holds water (potentially gallons of it), while the upper container holds the soil. Although, there are some designs that aren’t exactly made in this way, yet has a similar idea. The self-watering planter also needs an overflow hole, which allows water to drain if the reservoir is too full. You simply fill the container with water using a pipe or a hole through direct access to the reservoir.

When the water reaches the top of the reservoir, it will find its way out through the overflow hole. The overflow hole is also useful because it will prevent you to underwater or overwater your plants. The roots of the plants will eventually reach the water, but until that happens, the soil will simply wick the water up.

However, despite being so useful and efficient, self-watering planters are not good for all plants. Self-watering planters are designed for average plants under most conditions, so if you have a plant that requires very dry conditions, using self-watering planters may not be a great solution for you. This is simply because the plant will absorb more moisture than it needs, which could cause it to die instead of thrive. However, standard plants such as garden vegetables and annuals can do just fine in these containers.

Furthermore, self-watering planters are also extremely useful for busy individuals who are frequently away from home for several days. With the help of these planters, you know that your plants will be capable of taking care of themselves. Thus, you will not have to worry about the condition your plants are in while you are away.

There are several different types of self-watering planters you are able to use, depending on your needs. They are all based on a similar principle and allow the plants to absorb water as needed - not too much or too little. Self-watering planters can be purchased or can be made yourself if you are crafty and have the right containers to do it. All you have to do is simply add a reservoir beneath your favorite planter, or take two plastic containers of the same size and make a self-watering planter from scratch.

More information on how these planters work.

Outside Reservoir Type

Self-watering planters can vary in style and in order to know which one is best for your plants, it is useful to learn a bit about each of them. This type of self-watering planter features a simple design and it is very easy to make at home yourself. It is great to use if you are planning to be away for a while - for example, when you go on a vacation.

How It Works

The outside reservoir type of self-watering planter differs from other planters due to the reservoir which is placed outside of the planter. A jug filled with water or a bucket serves as a reservoir and it is placed above the level of the planter. There is a cotton wick that runs from the reservoir to the soil, through which the soil draws water.

As the soil becomes dry, it draws water from the reservoir through the wick, which means that the plant will absorb exactly the amount of water it needs. As the reservoir is placed outside the planter or rather next to it, it is very easy to monitor the water level.

In this way, you always know whether the reservoir needs more water or not. In addition, it is best if you use a see-through jug in order to monitor the water level. In addition, you are also able to use a strip of cotton cloth for a wick if you simply don’t have cotton. Use a bigger water reservoir if you are planning a vacation, in order to make sure your plant will not be left without moisture.

Subirrigation Design

A subirrigation self-watering planter is the one with a water reservoir at the bottom. The design is once again simple and the planter itself is very efficient. It needs refilling at 1 to 5 days interval, which gives you more time to enjoy other activities.

How It Works

The subirrigation design self-watering planter features an empty space at the bottom that contains water. The soil is above the water reservoir in another container and there are holes between the two containers, in the divided space between the water reservoir and the soil. Wicking chambers extend to the water reservoir, allowing moisture to move up to the soil.

This self-watering planter is designed carefully, so as to not allow the soil to get too wet. There is a fill tube on the container through which you are able to refill the reservoir when it is empty. If the container is overfilled, there is an overflow hole designed specifically to allow excess water to drain. The frequency of adding water to the water reservoir depends on the size of the planter, as well as on whether it is kept inside or outside.


If you were not aware, self-watering planters have many benefits. First of all, it gives you a much-needed break from the constant watering. As a result, you will have more free time on your hands to actually enjoy the beauty of your garden and be able to grow a wider range of plants than ever before.

The capillary system allows the roots to draw water from the reservoir through the wick when the soil dries out, keeping it moist at all times. Because of this, the soil will never get soaked or smelly. Furthermore, the roots are held away from the water and protected from diseases and fungi.

In addition to that, self-watering planters will save you a lot of water, as well, as it is reused by a built-in draining system that collects any excess or water overflow. As a result, you will no longer have to keep turning your faucet on and off. Thus, saving you money, as well, in the long-term.

Tips and Timing

An additional advantage of self-watering planters is that you are able to add fertilizer directly into the reservoir to provide nutrients for your plants during the growing season, making them stronger and healthier.

Moreover, it is best that you clean your reservoir regularly. To do this, snap off the planter’s bottom to reach the reservoir and remove salts and algae build-ups. To prevent mosquitoes breeding in your water reservoirs, add a couple of oil drops to the water every time you refill them.

These self-watering planters are ideal to use in areas with four different seasons and they will provide an average amount of moisture for your garden vegetables, annuals and perennials. However, if you live in an area with a tropical climate, or have plants requiring a lot of moisture, self-watering planters are, unfortunately, not an ideal option for you.

Lastly, don’t let the soil go completely dry, as the wick will lose its ability to draw water from the reservoir. Track your water levels and refill reservoirs every 2 to 5 days, depending on the size of your planters, as well as the temperature and humidity.

Watering from the Top or Bottom

After placing a plant in a self-watering planter for the first time, water its soil from the top for the first week or two. This will help its roots get stronger and eventually draw water on their own from the reservoir at the bottom.

Once the adjustment period is over, you have to avoid watering your plants from above, as doing so will cause the soil to be oversaturated with water, which will only lead to your plant’s deterioration.

However, if you prefer to water your plants from the top, consider removing the reservoir and draining the excess water in a way that it won’t be soaked up by the plant afterwards. If you fail to do so, the plant’s roots may be drowned in water that cannot be absorbed, which will then lead to damage and the plant could die.

If you use self-watering planters, water your plants from the bottom, topping up the reservoir water level. If you wish to continue watering your plants from above, it is advisable to go for a regular planter instead of a self-watering one, as it can cause more harm than good in this particular situation.


To reiterate, the use of self-watering planters come with many benefits: they help you save time, energy and water. Not only that though, you will eventually save more money in the long run too, as you won’t be watering your plants as often as before. In addition, with the time you have spared, you will have more time to spend on other things that you enjoy. For example, spending time with your family, spending quality time with yourself, or spending time appreciating your garden as a whole.

Self-watering planters are especially useful and convenient if you have a vast garden or greenhouse full of plants. What’s more, they help you maintain the optimal level of hydration for your garden plants, under the average temperature and humidity conditions. Using a self-watering planter, your plant will absorb only the water it needs, draining the excess back to the reservoir for a later use.

These planters are commercially available and come in different styles and sizes, but you also have the option to easily make your own, especially when you need to temporarily turn your regular planter into a self-watering one.

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