How to Make Your Established Lawn Drought Resistant

By Richard Flowers, ACCNP, Green Thumb Nursery, Ventura

Richard Flowers is an Advanced California Certified Nursery Professional (ACCNP), a certification awarded by the California Association of Nurseries and Garden Centers (CANGC).

With recent droughts, water-use programs, and media coverage, you have probably heard that lawns should be removed because they drink too much water. That is only partly true. The truth is that an already existing, well established lawn that has been in the ground for several years can take far less water than you would imagine. Instead of tearing out your old lawn and installing a whole new drought-tolerant landscape, you can keep the lawn you have and make it stronger, hardier, and more resistant to drought. It takes a little time and a change in your watering and mowing habits, and the lawn may look a bit longer than the putting-green ideal, but the payoff is a healthier lawn that needs far less water. You may also need to accept some temporary discoloration during extended heat and drought. Before we get into the how, here is why keeping your lawn is worth it.

Why Keep Your Lawn Instead of Ripping It Out?

A lawn provides real environmental, lifestyle, and health benefits. Grass cools the air and helps filter dust and pollutants, which is why turf feels so much cooler underfoot than concrete, bare soil, or artificial turf on a hot afternoon. That cooling lowers the temperature around your home and can ease your energy use in summer. Grass also takes in carbon dioxide and releases oxygen, holds soil in place against erosion, and gives kids and pets a soft, safe place to play.

Many people are now replacing lawns with artificial turf or California native plants. Natives are wonderful and use little water, but a living lawn still does things a plastic surface cannot. Artificial turf is a petroleum product, so consider the carbon footprint and pollution created to manufacture it. It uses no water except for the occasional rinse, but it provides none of the air-cooling, oxygen, or erosion benefits of real grass. Synthetic turf actually makes an area hotter and can burn bare feet in summer. It looks tidy, and that is about all it does.

Warm-Season vs. Cool-Season Grass and Water Use

Most lawns are either a warm-season grass or a cool-season grass. Warm-season types like St. Augustine and Bermuda generally use less water than cool-season fescues such as Marathon, and they tend to hold up better under tight watering restrictions. Both are still good options for Southern California. Whatever you have, an established lawn rarely needs more than about one inch of water a week, including rainfall.

The most popular grass here, Marathon, is a tall fescue, and it takes far less water than people assume once it is watered correctly. Tall fescue grows the deepest roots of any cool-season grass, commonly 2 to 3 feet down in good soil (Oregon State University turf program). A deep root system lets the lawn pull moisture from well below the surface and ride out heat and drought, and it means you can water much less often. The catch is that the grass only builds those deep roots when you water deeply and infrequently, which is the single most important step in a drought-tolerant lawn.

Grass	Season type	Relative water use	Notes for Southern California
Bermuda	Warm-season	Lower	Loves full sun and heat and is very drought tolerant once established; goes tan during winter dormancy
St. Augustine	Warm-season	Low to moderate	Takes some shade and coastal conditions; coarser blade
Tall fescue (Marathon)	Cool-season	Moderate	Stays green year-round and has the deepest roots of the cool-season grasses (2 to 3 feet), so it is drought tolerant when watered deeply and infrequently

Water Deep and Infrequently: the Core of a Drought-Tolerant Lawn

Most people water their lawn the wrong way, running the sprinklers for about 15 minutes every day. Shallow, frequent water trains the roots to stay near the surface, where they dry out fast. Instead, water for a longer stretch with a sprinkler that delivers slowly, roughly 3 or 4 hours once a week, to mimic a slow, steady rainfall. Over time the roots chase the water downward and stop depending on frequent sprinkling. Deep watering plus deep roots equals drought tolerance and a stronger, healthier lawn.

The goal each time you water is to wet the soil to a depth of about six inches, assuming no rain has fallen (Clemson Cooperative Extension). Aim for about one inch of water per week total, adjusting for weather (EPA WaterSense). Make the change gradually over a few weeks so the grass can adjust to the new schedule rather than being shocked into it.

How to deep-water an established lawn:

1. Water about once a week, and even less often in cool weather, instead of a little every day.
2. Run the sprinklers in one long, slow soak of about 3 to 4 hours so the water sinks in instead of running off.
3. Wet the soil to a depth of about 6 inches each time you water.
4. Aim for about one inch of water per week in total, including rainfall, and adjust up in heat and down in cool or rainy weather.
5. Make the change gradually over a few weeks so the roots have time to grow deeper.

Fix Your Sprinklers: Head-to-Head Coverage and Matched Output

How often have you driven past a lawn with water running down the gutter into the street? That wasted water is usually not the lawn’s fault, it is the sprinkler settings. In fact, as much as 50 percent of the water we use outdoors is lost to wind, evaporation, and runoff from inefficient watering (EPA WaterSense). Watering a lawn correctly is the real challenge, and it starts with your sprinklers.

First, make sure you have head-to-head coverage, meaning each sprinkler throws water all the way to the next sprinkler so the whole lawn gets even coverage. Second, your heads need matched precipitation rates (the gallons per minute, or GPM, each head applies) so some areas are not soaked while others stay dry. Check the label when you choose heads and keep them consistent. Drip and micro-sprinklers are rated in gallons per hour (GPH), but the same matching principle applies. Many of the sprinklers and timers Green Thumb carries are low-flow or pressure-regulated to help conserve water. If a head sprays the sidewalk, fence, or street, adjust its arc or swap it for the right pattern so the water lands only on the grass. Where runoff or erosion still happens, shorten the run time or split it into shorter cycles.

Water Early, Adjust to Conditions, and Use Smart Timers

Water in the very early morning, when less is lost to evaporation and humidity is higher. Watering in the heat of the day wastes much of it before the soil can absorb it (EPA WaterSense). The biggest mistake is the set-it-and-forget-it schedule that runs the same way all year. Instead, adjust your watering every week or two to match the weather and the season, and scale back gradually over several weeks when conditions call for less, so the grass can acclimate. In shade, water less, since shaded areas stay moist longer. During severe shortages, shut off the automatic system and hand-water only the areas that truly need it.

Smart irrigation controllers take much of the guesswork out of this. These timers use local weather data or soil-moisture sensors to decide when to water, and many include rain shutoff so they skip a cycle when it rains. A good smart controller can be programmed around local water restrictions and controlled from your phone. Many Southern California water districts offer rebates for weather-based smart controllers, so check with your local district for current programs. Green Thumb carries a range of smart timers if you want help choosing one.

Mow Higher and Grass-Cycle

Let your grass grow a little longer to conserve moisture and reduce stress. The rule of thumb is to never cut off more than one-third of the blade at a time (UC Integrated Pest Management); taking more stresses the plant and slows its recovery. For tall fescue, mow on a higher setting, around 3 to 3.5 inches (Clemson Cooperative Extension). Taller grass shades its own soil and keeps the roots cooler and moister, while scalping the lawn heats the soil and pushes thirsty new growth.

While you are at it, grass-cycle. Leave the clippings on the lawn, or use a mulching mower that cuts them fine and drops them back onto the turf. If you do not have a mulching mower, take the bag off, mow, rake the clippings out, mow again to chop them finer, then water them in. Within a few days they break down, especially in summer, feeding the lawn, improving the soil, and reducing how much water and fertilizer it needs over time. Electric or battery mowers are a greener option if you want one.

Dethatch, Aerate, and Top-Dress

Dethatching and aerating help water soak in instead of running off, which encourages the deep roots that make a lawn drought tolerant. Dethatching removes the dead stems and debris that build up under the grass, where they can harbor insects and disease and block water from reaching the roots. For a small lawn you can power-rake it; larger lawns call for a dethatching machine. Aeration pulls small plugs of soil from the lawn, relieving compaction so water, air, and fertilizer move freely into the root zone, and it also helps sandy soils hold moisture longer.

After aerating, spread a thin layer of organic compost such as Kellogg’s Topper over the lawn. It works its way into the soil, improves it, and helps the grass grow better. For small areas you can aerate yourself with a hand aeration tool.

Fertilize Organically and Crowd Out Weeds

Organic fertilizers feed the soil’s microbial life, which in turn makes a lawn more drought tolerant. They release slowly, last longer, and do not leach into groundwater the way high-nitrogen synthetic fertilizers can. High-nitrogen products are high in salts and force a fast surge of growth, which makes the grass grow quickly and demand more water. If you like, use a standard higher-nitrogen fertilizer to jump-start the lawn early in the growing season, then switch to an organic fertilizer through the rest of the season. A strong, well-fed lawn also naturally crowds out weeds, which otherwise compete with your grass for water and nutrients.

Prefer to Replant? Drought-Tolerant Options

If you would rather reduce the lawn than keep all of it, you have good options. You can shrink the lawn and fill the rest with California natives or other drought-tolerant plants, or replant with a tougher grass. For a rundown of grass varieties that handle dry conditions, see our guide to drought-resistant grasses, and if you are weighing sod or ground-cover alternatives, our guide to the best grass and sod options for a SoCal lawn compares the main choices. To water whatever you plant more efficiently, a drip irrigation system is hard to beat, and you can find more ideas in our guide to projects that reduce your lawn size. Stop by your local Green Thumb Nursery and our garden experts will help you choose.

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Drought-Tolerant Lawns: FAQs

Can an established lawn be drought tolerant?

Yes. An established lawn can become drought tolerant without being removed. Water it deeply and infrequently so the roots grow deep, mow higher, fix your sprinkler coverage, and feed it with an organic fertilizer. A deep-rooted lawn needs far less water and holds up through heat and drought.

What is the most drought-resistant grass?

Among common lawn grasses, a deep-rooted tall fescue like Marathon is very drought tolerant once it is watered deeply and infrequently, and warm-season grasses such as Bermuda use even less water. The grass variety matters less than how you water it. For a full comparison, see our guide to drought-resistant grasses.

How often should I water an established lawn?

Water about once a week, giving one long, slow soak that wets the soil to roughly six inches deep, rather than a short daily sprinkle. In cooler weather you can water even less often. Deep, infrequent watering is what drives roots down and builds drought tolerance.

Do warm-season grasses use less water than fescue?

Generally, yes. Warm-season grasses like Bermuda and St. Augustine usually need less water than cool-season fescues and tolerate tighter watering restrictions better. A well-managed tall fescue can still be drought tolerant thanks to its deep roots.

How much water does an established lawn need per week?

About one inch of water per week, including rainfall, is a good target for most established lawns, adjusted up in hot weather and down in cool or rainy stretches. Delivering that inch in one deep soak, rather than several shallow ones, is what makes it count.

Sources

• Statistics and Facts, EPA WaterSense
• Watering Tips, EPA WaterSense
• Healthy Lawns, Mowing, UC Integrated Pest Management
• Tall Fescue, Oregon State University Turf Program
• Tall Fescue Maintenance Calendar, Clemson Cooperative Extension