Overseeding with perennial ryegrass is key to keeping your sod grass lawn vigorous through a Southwest AZ winter.
The best time to overseed your sod grass lawn in Arizona is during the first half of October, or when the evening temperatures regularly stay below 65 degrees.
Keep in mind that overseeding your lawn takes effort and patience, but you’ll be pleased with the results!
AZ Winter and Fall Overseeding
Here are some simple steps on how to overseed your lawn from the pros at Ground Zero:
#1. Scalping
To ensure a good overseeding, you will need to get rid of the thatch that accumulated over the past summer.
Scalping is the removal of leaf and thatch accumulation to ensure the seed gets down to the soil.
Drop your moving height down to 1/4” to 1/2” to remove all the green tissue. Keep in mind that you may have to mow your law a few times to accomplish this.
If you still have too much thatch, a power rake is a bladed machine that will quickly loosen and rake the thatch. Rake your lawn in two directions with the take, mow over it one more time, and collect the clippings.
Now, your lawn should be very brown with 1/4” to 1/2” of stubble and just a bit of soil showing through.
It’s ready to seed at this point.
#2. Seeding
Your lawn will be better quality if you invest in some good, cool season grasses. Perennial ryegrass is quality, plus it’s suited for the AZ desert climate soil temperatures.
Depending on how vigorous and tall you prefer your lawn to be, the amount of grass seed that you will need varies:
Home Lawns (1” to 2”) – 12lbs. per 1,000 square feet.
Home Lawns (1/2” to 1”) – 15lbs. per 1,000 square feet.
Golf Course Tees (1/4”) – 20lbs. per 1,000 square feet.
Golf Course Greens (less than 1/4”) – 30lbs. per 1,000 square feet.
Spread half of your ryegrass seed in one direction, and the other half in the other direction, perpendicular to the first.
If you overlap or skip too much, you’ll have thick and scarce stripes all over your lawn.
It’s vital to spread grass seed as evenly as possible for the best results.
#3. Fertilize
Fertilize with a starter fertilizer before turning on your water. The mix should be similar to a 6-20-20 (6% nitrogen, 20% phosphorus, 20% potassium) or 15-15-15 (15% each of nitrogen, phosphorus and potassium) mix.
Follow the directions on the bag and make sure that you understand what all the different numbers mean to ensure you are making the correct choice for your lawn.
#4. Mulch
You don’t have to mulch, but you should if 1.) you don’t have a good irrigation system, 2.) don’t have a timer that waters 4-5 times per day, or 3.) the temperatures have dropped too quickly.
Well-composted mulch helps your lawn retain moisture and heat. After you spread the seed, spread the mulch 1/8” to 1/4” thick over the lawn.
#5. Water!
You want to maintain a moist seedbed for 7 to 10 days to allow the seed to germinate.
You’ll need to water 4 to 5 times per day for short cycles with no puddles, or dry spots.
After the seed has germinated and grown 3/4” to 1”, you can reduce the watering to 2 to 3 times per day.
After 10 to 14 days, reduce your watering to once per day.
Once your lawn is established, you’ll be able to water every other day through the winter. When the temperatures begin to rise again in the spring, you may need to water every night, depending on the needs of your specific lawn.
#6. Mowing
10 to 14 days after germination is the first time you should mow your lawn. If you prefer your grass a little longer, you may not need to mow for 2 to 3 weeks.
Follow the 30% rule for mowing, never remove more than 30% of the grass at a time. This will prevent you from pulling out the new, young seedlings.
Regularly maintain your sod after your ryegrass is established.
#7. Turf Nutrition
Feed your ryegrass monthly with an analysis like 21-7-14 or 22-3-9.
Look for a fertilizer that contains iron or uses “ironite” products for best results.
Iron also comes in a variety of liquids that you can spray on your turf.
For questions on specific turf nutrition, ask your local garden center for more information.