Saving water with Ollas
Our modest little urban farm would soon demand over 120 gallons of water per DAY; threatening to set us back by ~$70/month in water costs alone...something had to change. Since we love growing our own food, and we've set aside over 3,000 sq-ft of land for this purpose, size reduction wasn't an option.
So, we attacked the water "problem".
Attacking The Problem
We considered many water conservation ideas: buried soaker hoses, drip watering, surface hoses, water wicks, and the good 'ole flood watering strategy. Most of these ideas simply wouldn't work for us; we planned to use collected rainwater, and drip watering systems are not tolerant of "dirty" rainwater, flood strategies (which is what we started our urban farm with) lose a great deal of water to evaporation, and the other systems just "felt" too complicated.
Then, I stumbled across a weird idea dating back 4,000 years. Argued to be "...the most efficient irrigation system in the world..." We're already staunch believers, and our first season isn't even over yet...oh, and the neighbors are jealous of our bountiful crops (even though we got a very LATE start this year).
Identifying A Solution
That 4,000 year old idea is called an "Olla" (pronounced: Oy Yah). These little things are nothing more than an unglazed clay/terra-cotta pot, formed into a bottle or tapered shape, and buried deeply enough that only its top/neck remains exposed above ground. Keep the pots topped-off with water (our garden requires about 10 minutes of my time per day for this), and these little pots do the watering for you; maintaining a constant moisture level in the soil, and delivering water directly to the root areas.
Here's the key part though. Ollas don't just empty as they're filled. If the soil is already moist enough, then soil/water surface tension prevents the Olla from releasing its stored moisture. This simple little quirk turned that dumb clay pot into a seemingly high tech automated watering system - with no electronics or moving parts required. As the plants sip up water, the Olla replenishes moisture; it's really that simple.
Ollas are extremely popular in arid climates. For more details, an excellent primer can be found at PermacultureNews.
Locally, we found some really nice, but also really big and expensive options through PlugAndPlayGardens. We have four of these Ollas, and while they're useful, their size makes it difficult for them to work well in our raised beds.
Then just up north, there's some very pretty Growoyas in Vancouver BC...that's still not local enough though...
Cost and ease of purchasing became our primary concerns...and nobody seemed to carry anything like what we wanted, locally.
Time to DIY
Needless to say, I purchased a kiln, clay slip, and hit the internet. After investing quite a bit of time into designing and making molds, we started churning Ollas out...and the moment they cooled enough from firing we buried them.
Our Olla Design
This picture is well over a month old, but it illustrates our general design and placement strategy. Just space them evenly throughout the garden, and you're good to go. The general rule of thumb is to position Ollas near target plants, no further than two times the diameter of each Olla.
The Garden Today
Today, our small start to urban farming requires less than 4 gallons of water per day...yet the plants are thriving well beyond expectation. Yep, you read that right: a mere 3% of the original estimated ~120 gallons/day is all we've needed after switching to Ollas. We're happy farmers.
Here's a few quick photographs of the garden today.
Obtaining Small Ollas
We're considering selling Ollas, we just haven't firmed-up some of the little details. If you're interested, please comment here, or watch this blog for purchasing information.