When wondering when to plant grass seed in Colorado, it’s essential to consider the type of grass you’re planting. For cool-season types, late summer to early fall is ideal. Conversely, warm-season grasses benefit from sowing in late spring to early summer.
In this article, we’ll delve deep into how and when to plant and overseed your lawn in Colorado. Whether you’re nestled in the bustling streets of Denver or perched in the tranquil foothills of the Rockies, we’ve got you covered.
Best time to plant grass seed in Colorado
Colorado’s climate and geography allow for the cultivation of both warm-season and cool-season grasses, each requiring planting at different times to optimize their growth and health.
The key to a lush lawn is knowing not only the best grass seeds for your Colorado lawn but also how and when to plant them. Here are a few factors to take into consideration regarding when to plant them:
When to plant cool-season grasses in Colorado
Timing is critical for cultivating a lush, enduring lawn with cool-season grasses in the Centennial State. The ideal period for planting these grasses is when soil temperatures range between 50 and 65 F or when daytime temperatures hover between 60 and 75 F.
In Colorado, this sweet spot typically occurs from late summer to early fall. In more specific terms, for residents in and around Denver, the beginning of September is often the prime time to start planting cool-season grass.
If you missed the September window, you can also plant in spring. Just make sure you do it when soil temperatures are 50 to 60 F. You can check your city’s average soil temperature by date on GreenCast.
Here are our helpful, comprehensive guides on the most common cool-season grasses in Colorado:
When to plant warm-season grasses in Colorado
Warm-season grasses are best suited for Colorado’s hot summer temperatures, flourishing under the intense heat. The optimal time to sow the native warm-season grasses adapted to the state’s climate is in late spring to early summer.
Ideally, you should plant when soil temperatures start rising to between 65 and 75 F so the seeds can germinate. For residents in the Colorado Springs area, this window usually begins in early June.
The most common warm-season grass seeds in Colorado are:
- Buffalograss (check out our guide on Buffalograss)
- Blue grama
When to overseed in Colorado
Overseeding is a vital lawn care practice used to enhance the density of thinning turf, helping to create a robust and healthy lawn.
For cool-season lawns, the best time to overseed is in September if you’re in the Front Range or Western Slope area. This timing ensures that the seeds have enough time to establish before the onset of winter. For other areas, you can overseed from March through September.
Pro tip: Ideally, overseeding should occur at least 45 days before the expected first frost date in your area. If you miss this window and the first fall frost has already occurred, it’s best to wait until the next spring to overseed.
For warm-season grasses, overseeding should be timed for late spring or early summer, when soil temperatures are warm enough.
How to plant grass seed in Colorado
Planting grass seed in Colorado requires some planning and execution to ensure you do it right. Here’s how to plant grass seed effectively step-by-step:
1. Choose good quality seed
Start by selecting high-quality seed that is well-suited for Colorado’s climate and your specific yard conditions. For example, don’t choose grass seeds that need full sun if you have trees that cast shade in your yard.
Additionally, ensure that the seed mix has a weed seed rate of less than 0.5% to avoid unwanted growth. This will ensure that the majority of your seed flourishes without competition from weeds.
2. Clean the area
Before planting, thoroughly clean the area where you intend to sow the seed. Remove all debris, rocks, and weeds, and use an herbicide like glyphosate to completely eliminate any existing grass or weeds.
You can also do sheet mulching, a technique that involves smothering grass and weeds with paper, cardboard, or other organic materials, so it builds a good topsoil while getting rid of unwanted grass and weeds.
This step is crucial to prevent old vegetation from competing with your new grass for nutrients and water.
3. Grade the soil
Proper drainage is essential for a healthy lawn and to avoid damage to your home’s foundation. Grade your soil to create a gentle slope of about 2% away from your house. This slope will help prevent water from pooling near your foundation and ensure it drains efficiently throughout your lawn.
4. Aerate the soil
Aeration is key to successful seeding. Aerating the soil helps improve its structure, allowing more air, nutrients, and water to reach the root zone. It also helps improve seed-to-soil contact.
Use a core aerator to pull small plugs of soil out of the ground. This will help encourage deeper root growth on your new lawn and reduce soil compaction.
5. Spread the grass seeds
Use a broadcast spreader to evenly distribute the grass seeds over your lawn. Follow the seeding rate recommended on the seed package.
First, fill the spreader with half the amount of seed and walk in parallel lines across your lawn. Then, refill the spreader with the remaining half and apply it perpendicularly to your initial direction to ensure even coverage.
6. Rake the soil
After spreading the seeds, lightly rake the soil to help work the seeds into the top layer. This contact is important for germination.
Pro tip: The Colorado State University Extension advises against adding topsoil or sand over the seeds.
7. Apply starter fertilizer and water
Finish by applying a starter fertilizer to provide essential nutrients that assist with early growth. You can also do this before spreading the grass seeds. Be sure to follow the application rate specified on the fertilizer label.
To support germination, keep the soil consistently moist but not saturated. Water lightly and frequently until the seeds sprout, then change the schedule to deep, infrequent watering.
How much seed to use in Colorado
You have to apply the correct amount of grass seed to achieve a dense and healthy lawn. Using too much seed can lead to wastage and potential overcrowding; on the other hand, using too little can result in patchy areas where grass fails to establish.
Here is the recommended rate for each grass type, according to the Colorado State University Extension:
- Kentucky bluegrass: Seed at 3 to 5 pounds per 1,000 square feet
- Perennial ryegrass: Seed at 6 to 8 pounds per 1,000 square feet
- Tall fescue: Seed at 6 to 8 pounds per 1,000 square feet
- Fine fescues: Seed at 5 pounds per 1,000 square feet
- Buffalograss: Seed at 2 or 3 pounds per 1,000 square feet
- Blue grama: Seed at 1 to 3 pounds per 1,000 square feet
FAQ about seeding in Colorado
When should I fertilize my lawn in Colorado?
If you have a lawn with cool-season grass, like Kentucky bluegrass and tall fescue, the best time to fertilize in Colorado is in fall. For warm-season grasses, the ideal period is from mid-spring through summer.
Check out our Colorado lawn care schedule guide for more tips.
How to treat snow mold in Colorado?
The best way to treat snow mold in Colorado is by gently raking affected areas to break up the mold’s crusty surface and allow the underlying turf to dry out. Additionally, applying fungicides in the fall can help prevent the occurrence of snow mold.
Luckily, as the weather warms and conditions become drier in the spring, snow mold typically dies off naturally. However, you may need to reseed areas that are damaged.
Is Zoysiagrass good for Colorado?
No, Zoysiagrass is not recommended for Colorado. This type of grass thrives in regions with long, hot summers, which are not characteristic of Colorado’s climate.
Instead, the best warm-season grasses for Colorado are native varieties such as Buffalograss and blue grama, which are well-adapted to the local climate and soil conditions. You can also learn how to xeriscape your Colorado lawn, especially if you’re looking for a low-maintenance alternative to grass.
When to Call a Professional
Seeding your Colorado lawn doesn’t have to be a solo venture. If the thought of planting your entire lawn from scratch seems daunting, remember that local lawn care professionals are just a call away in Denver, Colorado Springs, and many other cities across the state. These pros can also help provide ongoing care to ensure your new grass remains vibrant and healthy.
Main Image Credit: Carol M. Highsmith | Wikimedia Commons | Public Domain
