OLLAS – A Potter’s Story
My name is Paul Carmichael. I have been a potter for 30 years, graduating from The National Art School, Sydney with a Diploma of Fine Arts.
After a varying career I became the Resident Potter at the Bribie Island Art Centre for 2.5 years, teaching both children and adults. I have had articles published in an international ceramics magazine as well as teaching pottery clubs in south east Queensland, including the Woodford Folk Festival for 7 consecutive years.
I have been residing in the Mary Valley in excess of 10 years and have developed and understanding of water conservation, which has resulted in my developing the Ollas.
Unglazed  Terra-cotta pots have long been used for the irrigation of crops. Ancient Egypt, China, North and South America etc have all used their own variation of this principle.
A simple 3 Litre pot can irrigate a square metre and that amount of water will last from 5 to 10 days depending on weather conditions and soil types. The Olla will then have to be physically refilled.
The great benefit is that the soil never dries out while there is still water in the pot, avoiding water stress to the plant itself while at the same time maintaining constant environmental support for vital microbial life.
A recent development of this principle uses for smaller vessels containing approximately 750ml, to be linked by 4mm poly pipe, which enables them to be completely buried. The Ollas then maintain the flow of water as it seeps out through the porous clay body.
No pumps, no timers, environmentally friendly and no mains pressure required.
If the syphon tube is removed from the water source, the water held in the underground Ollas keeps on seeping out, slowly being replaced with air. If the syphon tube is then put back into water , the syphon process begins again as the remaining water seeps out of the Ollas.
The trapped air in the Ollas only has one place to go and that is through the porous clay body, thus aerating the soil as well as irrigating it.
Common sense tells us that if a molecule of water can get  through, containing one oxygen atom and two hydrogen atoms, a lone oxygen atom is  able to find its way through. It is my understanding that that a nitrogen atom is even smaller but a carbon dioxide is larger than oxygen, yet still much tinier in size.
There are two possible problems using this underground type of Ollas:
  1. All Poly pipe connectors used with the Ollas must be sealed air-tight with some sort of sealant. This is because any air-leak wastes water and reduces the syphoning potential of any Ollas down the line. I have used Sikaflex, which has proven effective (a little messy, but very strong).
  1. Muddy water cannot be used. This is because clay floating in the water will reduce the porosity of the Ollas to the point of blocking them completely and forming a little dam inside each Ollas. Cleaning isn’t easy because they are completely sealed. The only way to clean them is to dry them out completely in the sun and then backwashing them. Where this is required, shake and empty out the muddy water and repeat until the water comes out clean.
The clay used for the Ollas comes from the land on which I live as does the wood used to fire them.
These Ollas are totally local with a tiny local footprint.
All enquiries are welcome, either by mobile phone on 0474 831 352, or email at [email protected].