Grass in the desert provides an island of cool in our scorching heat. But it also requires more water and care than desert-adapted plants. So here are some water-efficient tips for keeping your turf healthy and beautiful.
Most homeowners have some form of Bermuda grass, a grass that goes dormant in the fall and starts growing again in May. This life cycle means Bermuda does not need to be replanted each year and can handle the over seeding of a winter lawn. In May, when high afternoon temperatures kill the winter rye grass, Bermuda grass will reappear.
Most of us think that once the daytime temperatures hit 80 on a regular basis the Bermuda should start to green up. Yes and no.
A year like this one – when the temperatures go into the 90s for a week or so, see the grass green. But it may stop. That’s because for Bermuda to be in full-scale growth mode, soil temperatures need to be high on a regular basis. In years past when we were blessed with a long May spring with mild daytime temperatures – mid-70s to mid-80s – the nighttime temperatures were in the 50s and 60s and the Bermuda stopped growing. Despite the nice warm spring days, the soil was too cold for the Bermuda season to kick in.
Soil temperature at a depth of 3 1/2 inches is basically the average of the daytime high and nighttime low. So you won’t see Bermuda start to grow until the nighttime temperature is in the mid-60s for a week or two straight. Bottom line: Don’t waste fertilizer on Bermuda until you see new growth, and don’t aerate or dethatch until you see vigorous growth of your Bermuda or you may hurt the plant.
This is key: Whether you care for your own lawn or have a service, it’s important to watch over its maintenance. Some lawn services do the same thing with every lawn year in and year out. But it’s important to watch the weather for so many reasons in keeping a healthy yard.
As the Bermuda begins to grow, follow the guidelines below and you should be in good shape.
The key to watering is to apply no more than necessary and to water deeply. Only water often enough to avoid wilt between waterings. During the hot summer months, water lawns no more than once every three days. Remember to water deeply. Water long enough to move water to a depth of 8 to 10 inches into the soil – you can use a probe or long screwdriver to check the depth. The probe moves easily through moist soil and is resistant where the soil is dry. An interactive lawn watering guide is available online at Phoenix Area – Turf Water Management.
The best time to water is during the cool morning hours before 5 a.m. This helps minimize evaporation and prevents the growth of fungus.
Master Gardener Sharon Dewey recommends three applications of water an hour apart. For example, set the timer for 10 minutes, wait and hour and water another 10 minutes, and water 10 minutes an hour after that. This method allows the water to seem through our clay soils and really get deep.
Also, learn to operate your watering system so you can turn it off after rainy days. There’s no point in running a watering cycle in the days after a drench. That just wastes water and your money.
- If water runs off the turf, irrigate more often for shorter periods of time.
- Adjust sprinkler heads so they don’t spray walls, driveways or sidewalks.
- Replace broken and missing sprinklers immediately.
- Water shaded areas about 30% less than sunny areas.
- If it has rained, reduce irrigation accordingly.
Note: A typical residential lawn sprinkler system uses about 10 – 18 gallons per minute per valve or zone. If a lawn has two zones and waters for 15 minutes three times per week, the water consumption would range between 4,500 and 7,560 gallons per month.
Avoid scalping the lawn (mowing too closely). Grass that is too short uses more water. Adjust mowers so the grass height is maintained within these ranges:
|Hybrid Bermuda||½ – 1 inch|
|Common Bermuda||1 ½ – 2 inches|
|Perennial rye (winter grass)||1 ½ – 2 inches|
The mowing schedule also is important. During peak growing season (May – September for Bermuda) cut hybrid Bermuda grass kept at ½ inch in height every two to three days. If grass is kept at a height of 1”, mow every 4 – 5 days. Mow common Bermuda grass to 1 ½ inches in height every five to seven days.
- Don’t remove more than 1/3 of the grass at a time.
- Keep mower blades sharp.
- If you mow frequently, you shouldn’t need to bag your clippings.
- Avoid following the same pattern each time you mow.
- Increase the mowing height by 25% in shady areas.
Thatch is a mat of plant material consisting mainly of grass stems and roots. Excessive thatch is usually caused when turf areas are over watered or over fertilized. If thatch is over 1/2 inch, it should be removed.
Dethatch when Bermuda grass is growing at its fastest rate so it can quickly recover. A dethatcher should be set 1/8 to 1/4 inch above the soil to that it doesn’t cut the grass crowns or dig soil. You just want it to grab thatch. Start by setting the height on the dethatcher high and adjust it down if needed.
After dethatching, rake the thatch and then mow. You can den core aerate, add fertilizer and water.
Core aerating your soil will help relieve hard, compacted areas that cause puddling or runoff and inhibit root growth. The best time to aerate Bermuda grass is in May or June, when the nighttime temperatures have been in the mid-60s for more than a week and when the grass is growing quickly. Consider a manual spot aeration in high traffic areas. Use a core aerator, not a spike aerator. Core aerators pull plugs of soil out of the ground. Spike aerators just push soil in and compact it more.
Bermuda needs regular fertilizing for good growth and color during the growing season. But be careful, because an over fertilized lawn will require more water and more frequent mowing. A good rule of thumb is to apply fertilizer monthly during summer with a 3-1-2 ratio fertilizer, such as 27-7-14, and follow the directions on the manufacturer’s bag. More is not necessarily better. Also, the best time to fertilize grass is in the evening or early morning.
Weed, Disease and Insect Control
The best weed, insect and disease control is a healthy lawn. For additional information try:
Weeds – Urban Integrated Pest Management – Weeds
Turf Information – The University of Arizona Cooperative Extension has a large number of publications on turf maintenance.
Book – “Desert Landscaping For Beginners” has an excellent chapter on turf.
Compiled using information from Sharon Dewey, turf expert, Univ. Of Arizona Master Gardener Program; the “Desert Lawn Care Guide” from the Arizona Municipal Water Users Assoc.; City of Gilbert Water Conservation Dept.