This watering method is the secret to helping your dry garden thrive
Conserving water is essential for gardeners in the arid Mojave Desert. The most popular method for watering plants in our region is the drip system. Pioneered in Israel, this system is indeed excellent for delivering targeted water to a plant’s roots. It also reduces evaporation and water waste. But drip systems are better suited to vegetable gardening in arid climates.
For ornamentals, consider basin irrigation or basin watering. Commonly used for trees, this type of watering system is overlooked for cactus, agave, shrubs, and perennials that thrive in drought. It offers several advantages over traditional sprinkler systems, making it an optimal choice for desert horticulture.
Basin irrigation is uniquely adapted to desert climates
Basin irrigating involves creating shallow, saucer-like depressions, or basins, around individual plants or groups of plants. These basins are designed to capture and retain water, whether from rain or the end of your hose, so it can slowly infiltrate the soil and reach the roots of your plant. Importantly, basins deliver water uniformly around plant roots. This allows the roots to fully and completely colonize the terrain below a plant’s stems and foliage. In contrast, drip systems often emit water to the side of a plant. Roots grow toward the single source of water, instead of exploring the greater rooting area beneath the plant canopy.
Like drip systems, basin watering concentrates water at the root zone, thereby minimizing wasteful overwatering and surface runoff. Unlike drip systems, it does so deeply and uniformly. The slower, more gradual absorption of water into the soil promotes deeper root establishment. Plants are then better equipped to withstand extreme temperatures and prolonged drought conditions.
Two other reasons to basin water your ornamental plants
One. You’ll be more in tune with your garden. For the first year, you will need to manually fill the basins, requiring you to walk your new planting from time to time. You’ll notice what is thriving (or failing) much faster than if you had connected a set-it-and-forget-it drip system.
Two. You’ll spend more time gardening and less time fixing your drip system. Drip systems require constant maintenance. Our extreme heat and common rock mulches make leaks more common. While watering is no one’s favorite chore, it is an essential part of gardening in our landscape.
How to build your basins
Building a basin irrigation system is a straightforward process that starts at planting time. When planting, create a raised barrier around the base of each plant out of the leftover soil from planting. It should be about 2-4 inches high, with a diameter twice the width of the rootball. These basins should be replenished with additional soil as needed to maintain their shape and water-capturing capacity during the first two years in the garden.
Water is then applied directly into the basin after planting and every time the plant is watered thereafter. Use the shower attachment on your hose, or a watering pail, to fill the basin with water. Allow the water to drain, then fill it again.
How often to fill your basin
The frequency of watering will depend on factors like plant type, soil composition, and weather conditions. The goal of basin watering is to help the gardener hit that tricky sweet spot of “deep and infrequent” that appears on almost any desert-adapted plant label. Check soil moisture levels and adjust your watering schedule, taking care to avoid both over- and under-watering.
Basin watering helps your plants grow deep, wide root systems so that you will rarely—and sometimes never—have to water once they are established. Filling your basins (which is a very pleasant task) is accomplished with this purpose in mind.
A brief disclaimer: Watering is a complicated gardening activity. The advice you find here are suggestions. Use your judgment. Get in tune with your plants. If you are growing desert-adapted plants, you are far more likely to overwater. In fact, many plants that do well here will tolerate much less water than what many gardeners give them. But watering is not one-size-fits all.
For most desert shrubs, you’ll water twice a week after planting in early spring. If planting in fall, you can usually get a way with twice a week for a few weeks, then once a week, then withhold water throughout the coldest part of the winter. For the first full growing season, plan to water once a week, tapering off as you notice the plants start to establish.
In the low desert, it takes longer for plants to establish. You might have to continue basin watering into the second year. After that, the basins have begun to erode from rain and wind and your plant should be established. You can then water according to the plant’s needs. For many desert-adapted plants, especially those native to our region, this could be just a couple of times during the hottest part of year.
Get started
You don’t have to pull out your existing drip system or go around your garden building basins around older plants. Start small. As you start fall or spring planting in your landscape, try the basin approach. It will connect you quicker to your plants, giving you more time gardening and less time connecting tubes and pipes to your plants. It will also help your desert-adapted plants be more resilient. They will thrive in the hot, dry conditions of our climate just as they were meant to.
Mojave Gardener 