This is actually a garden project I had planned for last summer but only just finished up this month!
Last summer we went to a workshop on container gardening where we were introduced to the idea of global buckets (self-watering planters made out of old buckets). The idea isn’t something that will work for us (most of our planting is in raised beds) but while visiting the global bucket site I stumbled on another method of self-watering – the olla pot. Olla pots are clay containers which are sunk into the ground and filled with water. The water slowly seeps through the clay pot into the surrounding soil – a sort of time release watering system. Last summer we struggled to keep our zucchini bed watered so I thought something like this would be perfect for our sunny raised beds.
Olla pots looked easy enough to make – two clay pots, glued together and then buried in the garden. Unglazed clay pots were on sale at the garden centre for $0.10 so I bought 20 of them (enough for 10 olla pots) and set about making some. They were a disaster – the glue I used didn’t hold up to being underwater and within an hour of being filled up my olla pots all separated at the seam. I went back to the hardware store but they didn’t seem to carry a glue product that would work underwater for extended periods of time. Finally one of the guys at the store suggested that we visit an aquarium store. That was last July and it has taken 10 months but I finally made it to the aquarium store the other weekend and they stocked at least three kinds of underwater glue. Orca Glue promised to bond everything and work underwater so I bought a tube and went home to finally finish my olla pots!
The glue didn’t have any instructions (How long to let set? Damp or dry application?) but seems to have worked (I applied it dry and on both surfaces). I built a pot, let it set for a week, filled it with water and then tried to break it apart. Nothing moved and the water is only coming out the sides of the clay pot – success! I quickly finished off the remaining 9 pots – after almost a year my little garden project was done! In another week when the zucchini, squash and cucumber plants move outside I will plant my olla pots at the same time and hopefully they will work.
If you’d like to make your own (and I promise it doesn’t really take 10 months, more like an hour of work and some time for things to dry) here’s how I did it. What you need is:
- As many pairs of unglazed clay pots as you want to make olla pots (I bought 20 clay pots to make 10 olla pots). I think any size will work but mine have about an 8″ diameter top.
- Glue that works underwater (I used Orca Glue)
- Broken pieces of ceramic tile
- Light coloured paint
1. Paint the bottom (outside) of one of each pair of pots. This will become the top of your olla pot and the paint will help reduce evaporation. I used some leftover pale green paint.
2. Seal the hole in the bottom of the other pot using a piece of tile (these will be the bottom of your pots). I found some tile in our garage that I broke up and used. If you didn’t buy a house that came with random items like this in the garage you can pick up a few cheap tiles at the hardware store. I ran a line of Orca glue around the hole in the bottom of the pot and then a line of glue on the piece of tile and stuck it in. I put the unglazed side down. Let dry.
3. Run a line of glue around the rim of each pot. Stick a bottom pot (with the tile seal hole) and a top pot (painted) together to form a container. Let dry.
4. Test the pots by filling with water (I used a funnel to direct the water into the pots). Let them sit and make sure that they aren’t leaking at the seams. When you’re confident that they are sealed up, bury them in the garden near/with your plants. I haven’t done this yet but plan to install my olla pots at the same time as I put in my veggies.