Seeding strategies

Establishing a new seeding

The best time to establish a new seeding is between mid-late August and mid-September (August 15 –September 15). Kentucky bluegrass and tall fescue are better seeded in August, while perennial ryegrass can be seeded well into September. During this period soils are still warm, weed pressure is lower than it is in spring and the likelihood of rain is high. You can establish grass in the spring but success is influenced by variable weather, higher weed pressure and soil water content.

Steps:

1. Avoid soil compaction issues by minimizing the use of heavy equipment on a site to be seeded.
2. Till into the upper 6-8” of soil, organic matter (i.e. good quality compost) and lime if needed.
3. Complete final surface grade.
4. Use soil test results to determine the amount of phosphorus and potassium to apply. Use a York rake or similar tool to incorporate fertilizer into the upper 1-2” of soil.
5. Lightly rake the surface smooth and apply high quality seed at the recommended rate by applying ½ the seed in one direction and the other ½ in the opposite direction. Drop spreaders and rotary spreaders can be used under calm conditions. Incorporate the seed into the upper ¼ – ½” of soil. Lightly roll to ensure good soil to seed contact. Using a slicer or slit seeding is also commonly used.
6. Broadcasted seedings should be mulched to prevent soil erosion and increase establishment success, especially if irrigation is not available. Use weed-free straw and apply 50-90 lbs. per 1,000 sq. ft. to cover to about ½” thickness.
7. Lightly water daily until the first mowing.
8. Mowing can begin once grass reaches about 3¾” on a field that will be mowed at 2½”.
9. 3-4 weeks after germination apply ½ lb. of nitrogen per 1,000 sq. ft. or up to 1 lb. if using a 50% slow release source.

Overseeding small areas for quick cover

Broadcast perennial ryegrass at 4-6 lbs. of seed per 1,000 square feet.

Providing faster turf cover using pre-germinated seed

Mike Andresen, athletic field manager at Iowa State University, uses the following procedure on heavily used fields when faster turf cover is desired.

1. Begin with 50 lbs. of seed in a nylon bag.
2. Place the bag in a 50 gallon barrel and cover it with water and then cover the barrel with plastic.
3. Remove the plastic and change the water each day.
4. Aerify the area to be seeded on the 4^th day. Empty the water from the barrel and spread  seed by hand on the aerified area.
5. Apply a starter fertilizer and a recommended fungicide to control Pythium in the summer or Gray Leafspot if seeding in August.
6. Use a verticutter to slice in seed and break up plugs.
7. Lightly rake the area and roll with a medium-weight roller (200-500 lbs.).
8. Water the area until establishment is complete.

Dormant seeding for early spring turf cover

Dormant seeding is done in late fall or early winter and can increase the chance of having improved turf cover in the spring on soils that are poorly drained or soils frequently too wet to work. Dormant seedings can germinate 2-3 weeks earlier in the spring than conventional spring seeding.

However, to improve your chance of success the seeding must take place late in the season, when the average air temperature is below 50° and when there is no chance of seed germination, which usually occurs when the soil temperature is above 50°.  Check the soil temperature at the 1” depth to make sure it is not higher than 40-45°. The ultimate success of a dormant seeding is determined by the winter conditions. You can expect some seed mortality so the seeding rate at this time should be increased 50%. When seeding KBG apply 3-4 lbs. per 1,000 sq. ft. On areas that may be prone to erosion mulching is suggested to help stabilize the soil.

Another window of opportunity for dormant seeding would be during periods when the night time temperatures reach freezing, the day time temperatures warm up and there is no snow cover.  These conditions allow for the broadcasted seed to work its way into the soil. In the Northeast this time period occurs around late February or early March.

Sports turf seeding schedule

Adapted from Dave Minner, Iowa State University

Shaded areas indicate times when fields are in use.
Species:  KB= Kentucky bluegrass, PR= Perennial ryegrass, TF= Tall fescue
Method:  B= broadcast seed, C= cleat-in seed, D= drill seed