With a little planning, ollas are a viable and efficient watering mechanism for your garden. This is particularly true for gardens in hotter and drier climates, as ollas reduce the amount of water lost to evaporation and seepage. For travelers, ollas provide a short period of worry-free garden irrigation. Interested in learning more about ollas? Read the facts and see if ollas are right for your garden.
What are ollas?
Isn’t it fascinating that this irrigation method is believed to have been developed over 4000 years ago in North Africa and is still a staple gardening tool in some countries? These unglazed terracotta pots were brought to the American Southwest by Spanish settlers (Conquistadors) and Native American gardeners adopted them in their own gardens.
Ollas typically have a large, round base and a long-necked spout with a ⅕-inch to 3-inch opening. The base is the vessel that stores water for steady and continuous watering, while the neck is used to refill the base vessel.
How do ollas work?
If you have ever used a terracotta pot before, you may notice how it draws moisture from the soil, which is great for succulents, but not so much for water-loving plants. In an unglazed pot, this moisture will become available to plant roots outside the pot. Roots will sense the moisture and essentially suck it from the pot itself. This is why older sewer pipes made of terracotta and tar lining experience catastrophic breaks: large trees roots that sense the moisture will burst right through.
But ollas are efficient waterers. If your plant’s roots are small, a small amount of water will be released. More water will be available to larger, thirstier roots. Ollas can often be more efficient than modern-day drip irrigation systems, and cost less, too.
How to use ollas
Ollas are buried in the soil before you do your planting. When planning your garden, keep in mind that the amount of water leaving the olla is approximately equal to the radius of the olla. If you have a particularly large garden, you will need a larger olla or several small ollas spaced evenly.
Bury the olla in your garden soil, leaving several inches of the olla neck exposed. This buffer zone keeps the olla opening free of dirt and easily allows you to find the olla when replenishing its water. You can apply mulch around the exposed neck to prevent small amounts of evaporation. Next, plant your seeds or plants within 2-5 inches of the olla, depending on the size of the olla itself. If smaller, plant closer.
Lastly, fill the olla with water, which will now be almost entirely immune to evaporation. If your olla comes with a lid, use it to prevent dirt from entering the base and to ward off mosquitoes. If your olla didn’t come with a lid, a rock will work fine.
Maintaining your olla
Luckily, ollas don’t require much maintenance. A little guesswork will need to take place as you refill your ollas for the first time (this period could be days or weeks) since many factors contribute to how quickly water is absorbed: soil type, season, plant needs, and environment.
You’ll want to dig up and store ollas over the winter. If the olla contains trace moisture, it may freeze and crack. Otherwise, your olla should remain functional for years.
Creative Commons Flickr photo courtesy of cheeseslave