Winter Overseeding is Around the Corner

Good to Know

News and Announcements

Aug 22, 2012

Why Do We Overseed?

Many Southwest desert regions experience extreme temperature ranges.  Here in the Coachella Valley our annual temperatures can range from the mid-20s to mid-120s.  Since there is no one turf grass type that can remain healthy and green under these extreme temperature ranges, the warm weather Bermuda grass needs to overseeded with a cool season Rye grass in order to maintain green turf.

When to Overseed?

Soil temperature is the deciding factor in determining when to overseed with 70 %u2013 75° F at the 4-inch depth being the optimal temperature.  This typically requires evening temperatures to have lowered to 65-75.  Coachella Valley Association of Governments (CVAG), recommends overseeding between mid to late October for Homeowner Associations and residential owners.   Golf courses often begin the process sooner in order to be on schedule for their course opening dates.  When you are ready to seed, we recommend using a high quality Ryegrass blend.

How Much to Water?

While the seed is germinating, it is best to irrigate several times a day for short periods of time.   During this germination period (days 7-14), the grass seed only needs to remain moist - not wet.  For example if you are watering your lawn twice a day for 5-minutes, you will receive better results if you adjust your watering schedule to five 2-minute cycles per day.  According to CVWD, some of the local residents have doubled and even quadrupled the amount of water they use during overseeding due to the misconception that large turf areas need a lot of water to bring up their new lawn.  In addition to being unnecessary, over watering tends to wash away the seed which then requires additional overseeding and delays the end result.  You can reset your sprinklers back to normal once the seed is established.   Smart controllers are a helpful resource for setting the proper watering schedule during overseeding.

Over the past few years, CVWD teamed up with professional landscapers to determine the necessary amount of water during overseeding.  They measured and monitored test plots at College of the Desert and determined that a 50% increase in watering produced a healthy winter lawn.  While some facilities such as golf courses and tourist locations have required deadlines and economical reasons, they may increase watering to speed up the growth process. If you%u2019re not working with a green lawn deadline and want to enjoy the benefits of saving money and water, then just be patient. 

What is Smart Scalping?

The annual, local custom of lawn scalping releases an abundance of dust and pollen clouds into the valley air known as PM10.  PM10 which is particulate matter less than 10 microns in diameter or 1/7 the thickness of a human hair which is known to be the smallest particle than can be inhaled into the deepest part of the lungs.  These particles cause serious irritation to asthma and allergy sufferers and lead to further health complications.  These additional particles along with the valley's existing dust pollution are considered to be the area's worst environmental problem.

The University of California, Riverside conducted a three year study on alternative renovation methods using test sites at the Springs Country Club and Indian Wells Golf Resort.  At the conclusion of their study, it was determined PM10 emissions could be reduced by 99% using alternative renovation methods.

                                Old Scalping Method vs. Smart Scalping Method

           Old Method                                                                        Smart Scalping Method

1.  Seed early before Oct. 15th 1.  Seed after Oct.15th, if possible
2.  Shut off water 2.  Reduce water
3.  Scalp turf down to the dirt 3.  Gradually lower grass height
4.  Let dust fill the air 4.  Manage dust by dampening area with irrigation

In the meantime until seed growers develop a hardy perennial grass for our unique temperature extremes, we will continue to use smart scalping techniques and plan our fall events, golf games and entertaining around the germination of the grass.

Click on this Smart Scalping link to view the Residential Re-seeding Guide from CVAG.