If your lawn turns brown every November, you are not doing anything wrong. Bermuda grass is a warm-season grass, and it goes to sleep once the nights cool off. That is normal for the Sonoran Desert.
Overseeding with ryegrass in early fall is how Tucson lawns stay green through winter. The catch is timing. Seed too early and the heat cooks it. Seed too late and it never fills in before the cold. Here is the window our crews work with, and how to hit it.
Rather not spend your October weekend scalping a lawn? Our maintenance crews handle the whole job, from prep to first mow.
Call (520) 321-4678 or request a quote.
When to Overseed in Tucson: Late September to Mid-October
Tucson sits about 1,000 feet higher than Phoenix, so we cool off a little sooner than the Valley does. Most years the sweet spot for overseeding in Tucson is the first two weeks of October. In a cool year it can open the last week of September.
Watch the forecast, not the calendar. You are looking for three things:
- Nighttime lows settling into the low to mid 60s for a week straight
- Daytime highs dropping below 90
- Soil temperature around 72 to 75 degrees a few inches down (a cheap soil thermometer from any garden center works)
That combination tells you the bermuda is slowing down while the soil is still warm enough for ryegrass to sprout fast. Give it a week after the last real monsoon storm, too. Seeding into a washout wastes seed.
One local wrinkle: the Catalina Foothills and Oro Valley cool off before midtown and the south side. If you live up high, lean toward the early end of the window. If you are near downtown or out by Rita Ranch, the second week of October is usually plenty early.
Should You Overseed at All?
We will be straight with you, because we have been landscaping in Tucson since 1979 and we care about water. A ryegrass lawn drinks a lot during those first two weeks. Before you buy seed, ask what the lawn is for.
- You use it all winter. Kids, dogs, holiday guests in the backyard. Overseed it, and enjoy it.
- You use part of it. Overseed the part you walk on and let the rest go dormant. Dormant bermuda is alive, it is just resting.
- You never use it. That strip of grass nobody steps on might be happier as desert ground cover or a few well-placed accent plants. Less water, less mowing, more color in spring.
Which Grass Seed Works Best in Tucson
Perennial ryegrass. It sprouts in 5 to 10 days, handles our winter nights, and gives you a deep green that looks great against dormant bermuda. Skip annual ryegrass. It is cheaper, but it is coarse, it yellows early, and it can leave you with a thin lawn by February.
Plan on 8 to 10 pounds of seed per 1,000 square feet. Go a little heavier in shaded spots and areas that were thin last year.
Check Your Irrigation Before You Seed
Most bare strips we see in December are not a seed problem. They are a sprinkler problem. Before you scalp anything, run every zone and walk the lawn. Look for clogged heads, heads pointed at the wall, and spots that stay dry. New seed cannot survive a coverage gap.
If a zone is not throwing evenly, our Tucson irrigation team can tune it up in a single visit. It is a lot cheaper than reseeding twice.
How to Overseed a Tucson Lawn, Step by Step
- Ease off the water for 1 to 2 weeks before seeding. This stresses the bermuda so it does not compete with the new seed.
- Scalp the bermuda down to about half an inch. Bag every clipping. Seed needs to touch soil, not sit on a thatch mat.
- Dethatch or rake hard if the thatch layer is more than half an inch thick. Loosen the surface so seed can settle in.
- Spread the seed in two passes, one north to south and one east to west, at 8 to 10 pounds per 1,000 square feet.
- Top dress lightly with a thin layer of compost or mulch, about an eighth of an inch. It holds moisture and hides seed from birds.
- Apply a starter fertilizer the same day.
- Water 3 to 4 short cycles a day for 7 to 10 days. A few minutes each. The goal is damp soil, not puddles.
- First mow at 2 to 3 inches with a sharp blade. Then feed with a nitrogen fertilizer 3 to 4 weeks after seeding.
Once the lawn is established, back the water down to every other day, then follow your normal winter schedule. Deep and less often builds stronger roots.
What Happens in Spring
Ryegrass is a winter guest, not a permanent tenant. Around late April, when highs push past 90 again, start cutting back the water and lowering the mower. The rye will fade, the bermuda will wake up, and by June you are back to a summer lawn. Hanging on to the ryegrass too long is the one mistake that can actually damage your bermuda.
Weeds love this transition period. If you see spurge or nutsedge moving in, our weed and pest control crew can get ahead of it.
Want a green lawn this winter without the scalping, seeding, and 4-a-day watering schedule?
Horticulture Unlimited has kept Tucson lawns healthy since 1979. Ask about a maintenance plan and we will handle overseeding as part of it.
Call (520) 321-4678 or request a quote.
Overseeding Questions Tucson Homeowners Ask
Can I still overseed my lawn in Tucson in November?
You can, but expect slower results. Once nighttime lows drop into the 40s, ryegrass germinates slowly and fills in unevenly. In a warm November you may get a decent lawn by Christmas. In a cold one, thin spots can linger until spring. If you are past mid-October, seed heavier and keep the soil moist longer.
How long does ryegrass take to come up in Tucson?
With warm soil and steady moisture, perennial ryegrass sprouts in 5 to 10 days. You will usually see a green haze around day 7 and a mowable lawn in about 3 weeks. Cooler soil stretches every one of those numbers, which is why the early October window matters.
How much should I water new grass seed in Tucson?
Keep the top half inch of soil damp at all times for the first 7 to 10 days. In our dry air that means 3 to 4 short cycles a day, a few minutes each, not one long soak. Once the seedlings are up, drop to once a day, then every other day, so the roots chase the water downward.
Do I have to overseed my bermuda lawn every year?
No. Ryegrass dies out every spring, so a green winter lawn is a yearly choice, not a one-time fix. Plenty of Tucson homeowners skip it some years, let the bermuda go dormant, and save the water. The bermuda is not harmed either way.
Will overseeding hurt my bermuda grass?
Not if the spring transition is handled right. The risk is hanging on to the ryegrass too long in April and May, which shades and starves the bermuda underneath. Cut back watering, lower the mower, and let the rye fade as soon as the heat arrives. Your bermuda will be back by June.