When should you overseed your lawn in Scottsdale? Now. University of Arizona (UA) Cooperative Extension schedules winter grass seeding for October 10 to November 10 in Phoenix-area lawns, with the sweet spot arriving when daytime highs sit around 80 to 85°F and nights cool to about 55°F. Seed too early and the bermudagrass crowds out the rye. Seed too late and frost can damage young seedlings.
What do you overseed with? In the low desert, the standard choice is perennial ryegrass, seeded into an existing bermudagrass lawn just before the bermuda goes dormant. Done well, it keeps your yard green from roughly October through May. Here's the timeline, the prep and the watering schedule, all from the UA's published guidance.
Data note: Timing, seed rates, watering and mowing guidance come from UA Cooperative Extension publications AZ1683, "Overseeding Winter Grasses into Bermudagrass Turf" (October 2015), and AZ1817, "A Turfgrass Maintenance Guide for Residential and Commercial Lawns in the Low Elevation Arizona Desert" (April 2020).
Why Scottsdale Lawns Need a Winter Grass
Bermudagrass is the UA's best-adapted turf for the low desert's heat and water demands. It grows hard all summer, then slows in the fall and goes dormant. The UA notes that several continuous nights of frost in November or December turn it "blonde," and that the average first frost arrives in mid-November.
- Dormant bermuda: off-color for about three months in winter
- Overseeded rye: green from October through May
- Spring green-up: dormant bermuda typically greens in February, with active growth when soil holds about 60°F consistently in April
If your 85250 yard has a bermuda lawn, a green winter is a choice, not a requirement. The rest of this guide is for owners who want one.
When to Overseed: Your 85250 Timeline
30 Days Before Seeding
- Stop nitrogen fertilizer on the bermuda so it slows down instead of competing
14 Days Before
- Raise the mowing height 30 to 40%
- Cut irrigation by about 30%
1 to 3 Days Before
- Stop watering
- Mow back down to the original height
Seeding Day
- Lower the mower another 25 to 30% and leave clippings as mulch
- Seed at 12 to 15 pounds per 1,000 square feet of ryegrass
- Spread in two passes: half the seed one direction, half perpendicular
- Rake or drag lightly so seed contacts the soil
The UA cautions against aggressive dethatching or aerifying immediately before overseeding. Scalping too deep damages the rhizomes the bermuda needs for next spring's comeback.
Winter Grass Watering Schedule for Arizona
Weeks 1 and 2: Keep the Seed Moist
- Water 3 to 4 times a day for the first 7 to 10 days, until seedlings emerge
- Never let germinating seed dry out
After Establishment: Taper Down
- Gradually stretch to about once a week
- Keep the top 6 inches of soil moist
- Use the screwdriver test: if a long screwdriver slides in six inches and comes out damp, skip watering
Feeding and Mowing
- Fertilize 2 weeks after emergence with ammonium phosphate (16-20-0) at 5 lb per 1,000 sq. ft., then water it in
- First mow at 2¾ to 3 inches of growth, with sharp blades on dry grass
- Rotary mower height: 2¼ to 2¾ inches
Over-fertilizing, the UA warns, raises the risk of frost damage and disease and means more mowing.
Annual vs. Perennial Ryegrass
- Annual ryegrass: light green, coarse, fast-growing and inexpensive, with more frequent mowing
- Perennial ryegrass: deep green, finer leaves, better frost and disease tolerance; costs more and persists longer into spring
- Intermediate ryegrass: a hybrid with traits of both
Planning the Spring Transition
Perennial rye competes with bermuda as it greens up. In spring, the UA recommends lowering the mower about 35%, mowing more often, light weekly nitrogen, and steady irrigation until bermuda covers about 80% of the lawn. Bermuda then needs about 100 days of active summer growth before it's ready to be overseeded again.
“In my experience, November is when a lawn tells its story: you can see from the street who overseeded and who didn't. If you're listing this winter, a well-established rye lawn photographs beautifully. If you're staying put and want to save water and weekend hours, letting the bermuda go dormant is a perfectly respectable choice. Just keep it clean and edged.”
— Elizabeth Vijan, Tackett Team, eXp Realty
FAQ: Overseeding in Scottsdale
When should I overseed my lawn in Phoenix or Scottsdale?
October 10 to November 10, per the UA, ideally with 80–85°F days and nights near 55°F.
How often should I water winter grass in Arizona?
3 to 4 times a day for the first 7–10 days, then taper to about once a week once established.
How much ryegrass seed do I need to overseed bermuda?
12 to 15 pounds per 1,000 square feet, spread in two perpendicular passes.
Do I have to overseed my bermuda lawn?
No. Dormant bermuda is off-color for about three months, then returns in spring. Skip overseeding a brand-new bermuda lawn's first winter.
Listing This Winter? Let's Plan Your Curb Appeal
If you're thinking about selling in 85250 between now and spring, I'll walk your yard with you and build a simple curb-appeal timeline, from when to seed to what to refresh before photos, so your home shows at its best on day one.
Elizabeth Vijan | Tackett Team, eXp Realty
Chaparral Park Resident & 85250 Real Estate Expert
Plan My Winter Listing Prep · Call or text 602-885-7752
Sources: UA Extension: Overseeding Winter Grasses into Bermudagrass Turf (AZ1683) · UA Extension: Turfgrass Maintenance Guide for the Low Elevation Arizona Desert (AZ1817) · UA Turfgrass: Overseeding Bermudagrass tips
Disclaimer: General lawn-care information, not professional landscaping advice. Check your HOA's landscape rules and any watering guidance from your water provider before overseeding. Information deemed reliable but not guaranteed. Equal Housing Opportunity.
