Optimum seed date for fine fescue

By Emily Braithwaite and Alec Kowalewski, Oregon State University

Part of the multi-state USDA-SCRI fine fescue initiative was to identify ways that people can incorporate these low-input grasses into existing landscapes. We know that the fine fescue species persist in shade, with low water requirements, and low fertility requirements, but overcoming the social barrier for adopting more sites with these grasses was a primary focus of this initiative. In order to recommend this as a species for homeowners and turfgrass managers, it’s important to identify the best time of year to plant and establish the grass.

Oregon State University turfgrass researchers, along with scientists from Indiana, New Jersey, and Minnesota, initiated an optimal seeding date trial for fine fescues to identify which month of the year was best to seed fine fescues in different regions across the US. Nine monthly fine fescue seeding timings from March through November were investigated with a seed mixture of strong creeping red, Chewings, hard, and slender creeping red fescue (Figure 1). Prior to seeding, plots were sprayed with glyphosate to eradicate any weeds. The fine fescue mixture was then seeded into these plots at one of the nine predetermined seeding dates along with a starter fertilizer. Following seeding, plots were irrigated frequently to promote establishment. No additional fertilizers or pesticides were applied to plots following seeding.

Turfgrass research plots with a few of the plots having sparse growth
Figure 1. Optimal fine fescue seeding trial research plots (photo taken by Emily Braithwaite, August 2019).

Data collection consisted of monitoring weather data, observing the number of days until emergence, visual turfgrass cover and quality, and grid intersect counts to assess the percentage of weeds and fine fescue in each plot. Results from across all four locations showed that as temperatures increased during the growing season, the length of time required for fine fescue emergence decreased. Seeding in August and September, however, produced the best establishment with the lowest weed pressure. Oregon has much more of a Mediterranean climate compared to the other locations of this study, and as such that allowed for more flexibility in seeding timing. Overall, Oregon had a much wider seeding window of May through September (Figure 2).

Two images with a single plot outlined in black
Figure 2. A) Fine fescue seeded September 15, 2019; B) Fine fescue seeded July 15, 2019 (photo taken by Emily Braithwaite, May 2020).

For more detailed information about this study see: Braun,R.C., A.J. Patton, E. Watkins, A.B. Hollman, J.A. Murphy, B.S. Park, AR. Kowalewski, and E.T. Braithwaite. 2021. Optimal fine fescue mixture seeding dates in the northern United States. Agronomy Journal 113(5):4413-4428. https://doi.org/10.1002/agj2.20859