Till, kill, or spill: How and when should you establish a bee lawn

By Andrew Hollman and Dominic Christensen

Bee lawns are mixtures of lower maintenance turfgrasses along with flowering species to provide foraging resources for pollinators. Research at the University of Minnesota has been conducted to select grasses and forbs that maintain turf quality and traits. The success of this mixture of fine fescues, white clover, self heal and creeping thyme has led many people to attempt to establish a bee lawn. Through surveys and discussions with people who have established bee lawns along with those interested in the process, we have heard of differing levels of success along with concerns about the establishment process. In order to provide consumers solid recommendations and add to our knowledge, we are doing research to find the best methods and timing for establishing bee lawn plots. 

In our study, three different methods of site preparation were included: “Till”, “Kill” or “Spill” (Figure 1). The “Till’ method was the most labor intensive and involved tilling the site after it was killed, raking and smoothing it and then covering it with an erosion control blanket after seeding. The “Kill” method involved killing the existing turf with a herbicide and seeding into the dead vegetation. The “Spill” method involved overseeding into the existing living turfgrass. 

Three different seeding times were chosen: fall, dormant, and spring (Table 1). The fall timing is the normal recommendation for lawn establishment in the Upper Midwest, usually occurring between August 15 and September 15. Dormant seeding occurs in the late fall and relies on soil temperature being cool enough (below 40° F) to prevent the seed from germinating until the soil warms back up in the spring and is usually in mid to late November. Spring seeding occurs in the spring when soil temperatures become warm enough to kill existing vegetation and for seed to germinate. Research was carried out at the Turfgrass Research, Outreach and Education Center at the University of Minnesota (St. Paul, MN). The trial was initiated in the fall of 2024 and repeated in the fall of 2025. A perennial ryegrass stand was established in the spring of 2024 for the first trial and in the spring of 2025 for the repeat trial. 

We found that “Spill” produced the least desirable outcome with a high amount of existing perennial ryegrass and little to no fine fescue, creeping thyme and self-heal (Figure 2). Interestingly, though, white clover tended to increase throughout the summer suggesting that with minimal effort there could be some success in increasing white clover over time by using the “Spill” method. With the “Till” and “Kill” method a similar response was observed in general, showing a complete elimination of perennial ryegrass, and then fine fescue establishing to varying degrees depending on the timing of activity (Figure 2). Fall seeded plots, receiving the “Till” or “Kill” method, tended to have a much higher component of fine fescue, less self-heal, but similar amounts of white clover compared to other timings (Figure 2). Spring seeded plots were the slowest to establish, having less fine fescue, than dormant seeded plots but similar self-heal and creeping thyme compared to dormant seeded plots. There is some evidence that the “Till” method reduced the amount of self-heal, but more data would be needed to prove this point. 

In this study we found that method and timing are both important factors to convert a traditional lawn to a bee lawn. The “Till” or “Kill” method, both of which kill vegetation prior to seeding,  allow a much greater chance to change the overall outcome than timing alone. Fall seeding tended to result in a more grass-dominant plot. Homeowners should focus on killing existing vegetation (“Till” or “Kill” method), then dormant seeding a bee lawn mixture to provide the best chance to establish a bee lawn with the most amount of species. If that window is missed a spring seeding will also provide abundant species but establishment will take longer. For homeowners just looking to get some white clover into their existing lawn, they can have success by using the “Spill” method at any time, and then waiting a growing season for the white clover to establish.