Picture of self watering tray
This is a quick and easy project to construct a self-watering capillary tray.

It’s basically a tray with its own water supply, that you sit your pots in, and it automatically waters them for you. All you have to do is occassionally top up the main water reservoir, that’s all!

They’re great for seedlings, freshly rooted cuttings, and anything else that needs constant moisture.

How Does it Work?
This simple but effective device works by the principle of wicking, as explained below. In this setup, a terracotta pot (with its drain hole sealed) is used as a water reservoir. Beside it sits a plant in a pot. Both are sitting on capillary matting which absorbs water.
1.The terracotta pot slowly oozes water out onto the capillary matting.
The capillary matting, a synthetic absorbent material, soaks up water like a sponge.
The moist  potting  soil in the plant’s pot wicks up water from the damp capillary matting.

Now, some basic science. A property of water it that it sticks to itself – this property is called cohesion. It’s easy to understand when you consider that if you put two drops of water next to each other and push them together, they become one big drop!

Similarly to the way that small drops of water join up to make a bigger one, what happens here is that the water in the potting mix connects to the water in the capillary mat which connects to the water in the terracotta pot, and all three objects act like one big wick, drawing an even amount of water across themselves, and maintaining it as long as there’s water in the terracotta pot to draw from.

So, when the plant draws up the water in the potting mix or it dries out from evaporation, water will wick back into it to restore the moisture lost, so our plant gets its water supply and stays a happy plant, which is the way we prefer to keep them!
Remove these adsRemove these ads by Signing Up
kjohnson861 year ago

Glad I'm not the only one that was questioning the species of plant. LOL

brockchoy1 year ago
what is that plant called in the picture shown?
poetry2go1 year ago
Hi, I am looking for a solution to vacationing absences from my indoor herbs. How long does the reservoir last without refilling? For instance, could I fill it, leave for a week, and come back to living plants?
buirv1 year ago
Nice Pot Plants :-)
I was thinking those were pot plants by the small picture. Glad im not the only one who thinks so. How did the flowers turn out?
foobear1 year ago
Interesting tip, thank you