The principle is simple. An unglazed clay pot is buried with only the opening on top visible above the soil surface. It is then filled with water. The porous walls of the olla allow for water to dissipate into the soil as needed. Because the pores in the clay pot are small, the water does not freely flow out of the pot. A suction force is created by soil moisture tension as well as the plant roots.

If soil is dry, the water inside the olla will release faster as the soil roots “pull” it out. Likewise, if there is a recent saturating rainfall the water in the olla will remain until the surrounding soil dries. Therefore, olla irrigation is extremely water efficient and prevents excessive evaporation and water runoff. Plants are never over or under watered.

It is also better for the root systems of the plants. The roots will eventually grow towards and around the Olla promoting deep watering and dense root growth which facilitates more efficient nutrient and water uptake.

With ollas, soil and roots do not go through extreme drying and wetting cycles which is particularly beneficial to prevent bitter tasting greens, a challenge with gardening in arid regions. The consistent water also prevents cracks developing in tomatoes or melons which form if plants receive abundant and then scarce water. Additionally, with ollas the soil surface remains relatively dry in gardens which can prevent the growth of weeds and also helps minimize some unwanted insect populations.

• Conserving water
• If your water use is restricted.
• If you want to save time by watering less often.
• If you container garden.
• If you have a small area which is difficult to irrigate or gets sun all day.
• If you cannot water your plants on a regular basis (travel, work, life gets busy! etc.)
• If you don’t like to weed since water in an OLLA doesn’t water surface weed seeds.
• If you want healthier plants and better vegetable production since water is delivered at the root level.
• If you are gardening at a school or in a community garden with limited water access.

The OLLA spacing will depend on plant selection, soil type, and temperature. Optimum plant spacing and distance will also be influenced by the root system and size of the plant.

For instance, tomatoes are a large plant with an aggressive root system, so placing them at the edge of the wetting area will allow ample room for growth. The smaller plants can be planted right up to the neck of the OLLA.

This is determined by a few variables: how much water your plants use, soil type, temperature, and rainfall. Also, the OLLAS are hand crafted so there may be some minor variation among pots.

On a conservative side, fill the OLLAS 2 times weekly. You’ll find the pattern for your area with a little observation and common sense!

You can use the OLLA with any plant: vegetables and flowers, of course, but also trees and shrubs. Putting an OLLA by a new tree or shrub will help get the plant through that first year.

If you feel the root system is well developed after one year, dig the OLLA up and use it somewhere else. Keep in mind that woody roots from trees and shrubs are very strong and over 2 or more years could wrap around the OLLA and eventually crack it. Wisely use the OLLA to get these plants established, however long that takes, and then move the OLLA to use on another plant.

Your OLLA will last for years, with a little TLC.

If leaves or light things fall into the olla, fill the olla with water and as the item floats up, swish it out. If you find a lot of dirt has accidentally gotten in the OLLA, dig the OLLA up, tilt in on its side and spray the inside with your hose until the dirt washes out. You can clean your OLLA with a 1:1 mixture of vinegar and water. First, remove the OLLA from the ground if using a vinegar cleaning.

• Bury olla leaving 4-5 cms above the surface to prevent dirt and mulch from washing inside. Gently pack soil around the olla. Water will not disperse in air pockets and roots will not grow in air pockets.
• Use a good covering of mulch around the Olla.
• Check the water level frequently and refill the olla as needed. The frequency depends upon the soil type, surrounding plant density, and weather. At times it may need refilling every 7 days or more or as frequently as every other day.
• Always cover over the olla opening. This will minimize evaporation and prevent mosquito breeding, etc.
• Use ollas in slightly sandy or coarse textured soils. Soils with high clay content do not dissipate water well.
• If you have a very deep soil it is useful to place a saucer or drainage tray at the bottom of the hole where the olla is to be placed. This impedes water seepage bellow while promoting seepage outward.
• Plant seeds fairly close to the olla opening. Water the entire area and possibly surface water until the seeds germinate if your olla is not keeping the top surface moist.
• Liquid fertilizer can be added to the olla to slowly release nutrients into the soil. Make sure it is truly a liquid form as to not plug the pores of the clay.