How to make DIY Ollas: Low Tech SelfWatering Systems for ...
Jun 26, 2017· You make concrete by mixing one part of cement with two parts sand, and just enough water to get it moist but not sloppy. For a single olla you need about 1/2″ cup of cement and 1 cup of sand. Pour the concrete into the pot, making sure to plug up the hole with a bit of putty first, and let it harden for 24 hours.