Let's set the scene: You live in the Southwest and you just don't have time to water your garden. Maybe your home is in a water-restricted area, and you need to save water. But you still want a lush garden of beautiful flowers or delicious vegetables. You sound like someone who could use an olla garden.
Ollas (pronounced oy-yas) are porous, unglazed clay pots designed to be buried in loose soil. When the pots are filled with water, the moisture slowly wicks away from the pot into the soil to reach nearby plant roots. They were brought to the New World by Spanish settlers and used for centuries in the Southwest. Over time, Olla gardening was forgotten, but it's now coming back as more people become concerned about water usage in dry areas. Proponents of this irrigation method claim that you could save more water using ollas than even a drip system.
Normally, ollas are buried up to their necks in loose soil. If your soil is hard or clay, amend it with organic material and maybe a little sand. You can also put your ollas in your raised garden beds or even containers. If you want some of the ollas to show for decoration, just be sure to glaze or paint the exposed surface with a water-impermeable coating. Color and design are up to you.
It's a good thing that ollas come in different shapes and sizes, because so do plant roots. Plants with deep roots should be planted in clusters around deep ollas. Shallow-rooted plants go with shallow ollas. Your plant clusters can have a lot of variety, but try to use plants with the same water needs. You can find the ollas you need at your garden center or online.
Insects and animals might be tempted to get at the water in the olla, so it's a good idea to cover the opening.