Ryegrass overseeding in Arizona

Winter Overseeding in Phoenix: When to do it (and is it worth it)?

In Phoenix, where scorching summers take a toll on warm-season grasses, many homeowners wonder how to keep their lawns green year-round. The answer is winter overseeding — the practice of planting cool-season ryegrass over Bermuda grass to maintain color and curb appeal during the cooler months.But is overseeding really worth the effort? More importantly, when should you overseed in Phoenix, and how do you do it the right way? This guide breaks down everything you need to know.

Why Overseeding matters in Arizona

Most Arizona lawns are built on Bermudagrass, a warm-season turf that thrives in summer but goes dormant when temperatures dip below 65°F. By late fall, it turns brown and straw-like.

Overseeding with ryegrass in the fall solves this problem:
  • Keeps lawns green through winter: Ryegrass stays vibrant when Bermuda is dormant.
  • Boosts curb appeal and property value: A healthy, green lawn stands out in a neighborhood full of brown turf.
  • Prevents erosion and dust: Live grass holds soil in place, reducing dust during the dry winter season.
  • Creates a usable yard: Families and pets enjoy lush, green spaces all year round.

    For homeowners in Phoenix who are focused on maintaining the most beautiful lawn in the neighborhood, overseeding is often worth the minimal investment.
When to overseed in Phoenix:
  • Overseeding with ryegrass is best in late September through mid October. More specifically:
    • Daytime highs should be around 75-85° F
    • Nighttime highs should be below 65° F

If you seed to early, the heat will stress the ryegrass seedlings. If you seed to late, the cool temperatures may stunt germination.

Pro Tip: Overseeding right after the summer monsoon season, once the extreme heat has passed gives ryegrass the best chance to establish before winter.

How to overseed a desert lawn:

    Overseeding isn’t complicated, but success depends on proper preparation and follow-through. Here’s a step-by-step process:

    1. Prepare the Bermuda Grass
    Scalp the lawn: Mow Bermuda very short (½–¾ inch) to expose soil.

    Bag the clippings: Removing debris ensures seed-to-soil contact.

    Lightly dethatch or rake: Opens up the surface for ryegrass seed to settle.

    2. Seed the Ryegrass
    Choose perennial ryegrass for a darker, denser lawn.


    Seed rate: 8–12 pounds per 1,000 square feet for good coverage.


    Spread evenly: Use a broadcast spreader for uniform results.


    3. Water for Germination
    Frequent light watering: 3–4 times per day for 5–10 minutes.


    Keep soil moist but not soggy until seedlings establish (7–10 days).


    4. Adjust Watering After Germination
    Reduce frequency and increase duration once ryegrass is established.


    Settle into a schedule of deep watering 2–3 times per week.


    5. Fertilize for Growth
    Apply a starter fertilizer high in phosphorus when seeding.


    Switch to balanced or nitrogen-rich fertilizers as the ryegrass matures.


    By following these steps, you’ll encourage a smooth transition from dormant Bermuda to lush, green ryegrass.

    If you are in need of a free landscape evaluation or help with fertilization, feel free to contact Adaptive Plant Health & Weed Solutions or call (602) 777-7764