I'd like to build a self-watering planter from wood made watertight with something like a rubber pond liner. This would be larger than just a self-watering pot, with dimensions around 2' by 4' and a planting area maybe 2' deep.

The type of self-watering planter I am talking about is the kind with a lower chamber that you keep filled with water and an upper chamber that is larger and filled with soil/potting mix where the plants go with smaller "wicking chambers" that protrude below the upper chamber sitting in the water reservoir that have holes small enough for water to get in but not, I guess, big enough for the dirt to dissolve out into the reservoir.

I see a lot of designs on the internet in which people use plastic for the wicking chamber(s). I've seen simple designs using solo cups for example. The commercial products I see all use a plastic false bottom on the top chamber with the plastic forming the wicking chambers.

I am wondering if it would be possible to implement the design using less plastic. The use of solo cups for example seems like a bad idea to me because they strike me as flimsy.

  • Would it be possible to use standard terracotta pots as wicks? Would they be permeable enough for water to pass through in sufficient quantity for the system to work or would I need to drill holes in them?
  • Also in general are the designs I see on the internet using enough wicking chambers?
  • I understand the principle of the wicks but they are not magic --can one small plastic chamber really deliver sufficient water to an approximately 8 cubic feet planter as I see online?
  • How many chambers should I use?

1 Answer 1


A little late.

  • Terracotta would make a fine wick, as long as it is unpainted and unglazed. In India water used to be kept cold in terracotta pots, the evaporation through the sides would keep the water cool. If you soak a piece of terracotta, you can see that it soaks up water.
  • The size of the wicking chamber is irrelevant, as long as there is always enough water there. Commercial ones that we have, have the chamber as large as the main pot (in area) with about two inches of water.
  1. There are a whole lot of ideas to be gained here The 20 Best Self Watering Systems Of 2023

  2. We use this system for indoor plants, except ours are terracotta instead of ceramic.

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