This is a guest post by Mike Lieberman of the Urban Organic Gardener.
How to Make a Self-Watering Container
If you’ve ever seen any of those grow box products, that is what a self-watering container is. It’s just much cheaper to make on your own.
Once you have the tools, most of which you’ll likely have around your home already, it’ll cost you less than $3 to make one. That's much more affordable than the $50+ ones you can purchase.
There are several variations on making these. I’ll share with you the simplest and cheapest one that I’ve been using for the last two years.
Tools you’ll need:
● 1/4″ bit
● 3 1/2″ hole saw for metal and wood
● 1 1/4″ hole saw for metal and wood
Materials you’ll need:
● 2 food grade 5 gallon containers – 1 for planting container and 1 for reservoir container
● ½ pint deli container for wicking basket
You don’t have the buy the 5-gallon containers. I’ve found that any of the following places will gladly either give them to you or sell them to you for $1.
● Farmers markets
● Flower shops
I’ve had people tell me that they’ve established relationships with local vendors who call them to let them know that they have containers for them to pick up.
Instructions on how to make self-watering containers:
● Use the 1/4″ drill bit to drill holes in the deli container.
● Attach the 3 1/2″ hole saw attachment to the drill. Drill a hole in the bottom of the container. I’ve found drilling in a counter-clockwise direction to work best.
● Reattach the 1/4″ drill bit and drill holes in the bottom of the planting container to allow for drainage.
● Put the wicking basket in the middle of the reservoir container.
● Place the planting container in the reservoir container, aligning the wicking basket with the hole in the middle.
● There will be a little space between the wicking basket and the planting container. You can duct tape the basket to the bottom of the container, but it’s not necessary.
● Hold the containers up to the light. You should be able to see through the reservoir container where the planting container is. Using the 1 1/4″ hole saw, drill a hole 1/4″ in the reservoir container below where the planting container is.
● This is the hole where you will water the plant from.
● That’s it. You’re done!
How Self-Watering Containers Work
They differ from regular planting containers because in self-watering containers the roots suck up the water from the reservoir container below.
In a traditional container, you water the plant from the top. A percentage of the water you pour doesn’t even make it to the roots.
As I mentioned earlier, self-watering containers are made up of two 5-gallon containers. They are called the reservoir and planting containers. The outside container is the reservoir container. It holds the wicking basket and the water.
Following the instructions above, the planting container is placed inside of the reservoir container with the deli container centered.
When putting the container together, the wicking basket is filled with soil and then moistened with water. Then more soil is added to fill the planting container and moistened as well.
With about 2-3 inches from the top, place your plant and surround it with more soil, making sure to keep it moist.
You can water the self-watering container by removing the planting container and pouring water directly into the reservoir container until it reaches the overflow hole.
Since there are holes in the wicking basket with the soil, it will soak up the water and allow the plants' roots to drink up the water as needed. This is a more natural way for the plants to soak up water as opposed to watering them from the top. It also makes it easier to never over-or under-water the plant because you can tell by the overflow hole.
Depending on the plant, temperature and sunlight, you can water the plant once per week. I’ve gone away for up to three weeks and they’ve been fine.