Why and how self-watering container gardens work
Growing plants is amazing. Watering plants and keeping plants alive can become a bit of a problem if you live a busy life. How to water plants when you are on holidays is also a big challenge.
Having plants that almost water themselves makes gardening a lot easier and it will give you more free time and peace of mind.
A self-watering container garden – sometimes called a wicking bed – will make sure that your plants have enough water, even if you don’t have time to water them regularly.
There are many different tutorials on the internet and I want to share one of the simplest ways that produced a great result.
This design mimics a natural landscape with a high groundwater reserve for your plants. The roots will be able to get enough water to grow without getting waterlogged and dying.
This concept can be applied on different scales and will enable plants to survive while growing a healthy and strong root system.
The problem with traditional pots is that they get watered from the top. This trains roots to grow a lot in the surface area and not downwards. A lot of this water evaporates when it gets hot and roots don’t get trained to grow further down to look for water in dryer times.
Self-watering wicking beds change this and grow healthier root systems.
The building process
Step 1: Choose a container
You need a water-tight container. Small or large buckets work great for this. You can also create your own container by lining a box with pond liner.
Step 2: Add a filling material
Fill the bottom of the container to create a ‘second bottom’ for the soil. We used some old pipes that we found on the trash.
You can also use old containers, gravel or sand. The main goal is to create a storage layer for the water.
Step 3: Add a liner to separate soil from water
Root-stopping fabric works great. If you only have other fabric, that also works. The main idea is to prevent soil from falling into the water and turning it into mud.
The liner can go down to the bottom of the container to ensure contact with water even when the water level drops.
Step 4: Add a pipe to fill the container
We need to get water into the container. An old pipe works great for this purpose.
To make sure that the end of the pipe doesn’t get closed by the bottom of the container, you can cut it on an angle.
Step 5: Choose a spot for the inlet pipe
Add the pipe inside the container just outside the fabric. This allows water to flow freely into the container without a hole in the fabric.
You can use any kind of old pipe for this purpose.
Step 6: Fill the container with soil
Sandy loam soil with a moderate amount of organic matter works best for this purpose. You want to use a soil that can pull up moisture easily and doesn’t get too hard.
In this example, we used soil that we dug up on site. It has a high clay content and is not ideal, but we wanted to try using it anyways. It has worked quite well so far.
Step 7: Add an outlet for the water
The hole will ensure that the container doesn’t get too full.
This step is extremely important to prevent your plants from drowning. Make sure to add the outlet below the top of your filling material.
You want to ensure a dry layer between the water-level and your soil.
If the hole is too high, your soil will sit inside the water and not enough oxygen will reach your roots.
Step 7.1: Add a divider
Add a divider between the outlet hole and the fabric. If the fabric pushes directly into the hole, it can prevent the water from exiting and your container will fill too much.
In this example I just used an old piece of pipe. The material doesn’t matter, as long as it separates the fabric from th hole.
Step 8: Add a funnel
To make filling the container easier, we used an old bottle as a funnel. With a grinder, we took of the threats to fit it into the pipe. A funnel is not necessary but will make your life easier.
Step 9: Fill the container with water
You can fill it up until the water runs out of the outlet. You might need to fill the container a few times on the first day.
The water gets sucked into the soil and out of the container. This is possible because of capillary action of soi. You can learn how capillary action works on this site.
Once the soil is moist your system is ready to go.
(Don’t worry we didn’t buy water in plastic containers for this. We get water from the river with these containers.)
Step 10: Add your plants
You can plant many different plants into the system. It helps to use plants that already have a bit of a root system to help them reach the water.
If your plants are still very small, you might have to add some additional water from the top to start the growing process.
Step 11: Add a layer of mulch
This layer protects the soil from the sun, prevents evaporation and creates a cooler microclimate for the soil and plants.
You can use any kind of organic matter. As it degrades this layer slowly turns into soil and additional nutrients for your plants.
Step 12: Watch and enjoy
Enjoy your free time and watch your plants grow. Depending on your area, rainfall and sunshine, you will only need to refill the system every few weeks. If you live in an area with enough rain, you might not have to refill it at all.
The water storage inside the bucket will fill up with the rain and help the plants survive between rain events.
With some slight additions, you can turn this system completely automatic without having to water it at all. I will share the guide to those in a future post.
If you have questions about the design or some feedback on how to make it even better, please feel free to share them below.
Enjoy the process and happy planting <3