The best time to plant native grasses is in the early spring (mid March to mid May) when soil moisture is more abundant and temperatures are cooler. Late summer/early fall (mid August through September) can also be a good time but supplemental water may be necessary to get good germination. Dormant seeding in late fall or early winter also works well providing the soil is not frozen.
Preparing a good seedbed is very important to ensure proper seed to soil contact and provide a good growing environment. Rake, till or plow the site to loosen the top 3 to 4 inches (8 to 12 inches is ideal) of soil. Excess weeds or other undesirable vegetation should be removed or thoroughly worked into the soil. If needed, apply a high phosphorus fertilizer (18-46-0) at this time. The final seedbed should be smooth, free of large clumps and firm.
Drill seeding with a mechanical seeder is usually the most efficient method. If a seeder is not available, applying the seed with a cyclone type broadcaster works well for large areas. Hand broadcasting can be done for small sites. Once the seed has been applied, rake or drag the site to cover the seed with 1/4 to 1/2 inch maximum of soil (this step can be omitted if drill seeded).
Applying a light layer (maximum 1/4 inch) of straw or other organic material on top of the seedbed greatly improves the chance of success, especially if no supplemental water is available. Mulching also helps protect the seed from blowing away or being eaten by rodents or birds.
Lack of proper moisture during establishment is the number one cause of failure of most seeding projects in Colorado. Providing supplemental water to the site greatly improves the success rate (Mother Nature provides enough moisture during the growing season on average one out of every 3 years).
Weeds grow and establish much faster and easier than grasses, and can rob the soil of valuable moisture during the establishment period. The best method of weed control is by mowing the site before the weeds can mature and set seed. Chemical applications are generally not recommended unless you can spot spray areas of heavy weed growth.
Please Note: Do not mow if wildflowers have also been planted with the grasses.
Under proper growing conditions, you should start to see grass growth in 4 to 6 weeks with full development in 6 to 8 months. Depending on planting time, available moisture, and weed control, full establishment may take more than one growing season. The more care and effort you provide initially will greatly influence the establishment time and success.