By Gary Deters
Last year at this time, we established 120 research plots at four locations across the Twin Cities. This study is a collaboration which includes the cities of St. Paul, Lake Elmo, Savage, and Brooklyn Park. The plots represent 30 different turfgrass seed combinations, from single‑species to mixtures consisting of between two and seven species. This range lets us study how different mixes respond to weather stress and how they recover as the seasons change. Our team has found that when grasses are seeded on roadsides in Minnesota, the more species in a mixture, the better the mixture performed. Using four sites allows the same mixtures to be exposed to different soil types and a range of weather conditions, as each location receives varying amounts of rain and maintains different soil moisture levels, directly affecting turfgrass health and recovery. Trials like these take time because the turfgrasses need to go through a few cycles of stress from harsh conditions and periods of recovery, usually spanning a few years, before we know for sure if a mixture will be worth recommending for lawns.
We seeded in August because it is the best time to establish grass from seed as it has warm soil temperatures, shorter days, and longer nights which lowers stress levels by reducing the window for extreme heat that might harm the newly emerging seedlings. Establishing grass from seed can be a very difficult task, even for seasoned professionals when weather conditions do not cooperate. Common problems include extreme heat, heavy downpours, humidity which elevates the potential for turfgrass disease, low soil temperatures, high annual weed competition, and a lack of rain if the seeded plot has poor irrigation coverage. We wanted to conduct a study where some of those scenarios could happen naturally to a certain extent, including competition from weeds.
To make sure the establishment of our trial did not fail, we used erosion blankets to keep grass seed from spreading from plot to plot. Seeding blankets help to provide an excellent growing environment by keeping the soil moist, which aids in faster germination. The plots were seeded on August 8 (St. Paul), August 12 (Brooklyn Park), August 13 (Savage), and August 20 (Lake Elmo). All plots had good establishment going in the winter months (Figure 1) and came out of winter in good shape, with the exception of a few perennial ryegrass plots in Brooklyn Park. Each site received a fertilizer application of 0.5 lbs N/1,000 sq. ft in late April. Once fully established, the plan was to not provide any supplemental irrigation so we could evaluate these grasses for lawns that don’t need very much water. So far during the summer of 2026, we have received dry, stressful weather conditions and several plots have been pushed very hard. The important focus of the research will be assessing which mixtures are best at recovering from stress.
So what are we seeing right now? Some mixtures look better than others, and some species are holding a better green color (Figure 2). The grasses that need sufficient water like Kentucky bluegrass and perennial ryegrass are dormant and more thinned out looking than tall fescue or fine fescue. The plots at Brooklyn Park are all very severely drought stricken because that site has much sandier soils than the other three locations. All four sites have some issues with weed encroachment, with some plots being outcompeted by the weeds.
While visiting the site on August 14, 2026, images were taken from directly above each plot using a lightbox to provide consistent, shadow‑free, and evenly lit photos in a controlled environment, which is standard practice in research. Those images highlight how the same mixture of 50% Kentucky bluegrass, 25% tall fescue, and 25% hard fescue can appear differently across sites (Figure 3).
The heat and drought of summer are likely not yet over. Plots will not begin to recover until we receive sufficient rainfalls that completely saturate the soil and temperatures steadily decline with day and night time temperatures. A fertilizer application is planned in September as long as the grasses are no longer stressed and are actively growing. This will help speed-up recovery.
The results of this project should lead to seed‑mixture recommendations that we will share with both the companies that sell grass seed in Minnesota and the general public. We hope this leads to more Minnesota residents and municipalities choosing drought‑tolerant mixtures that conserve water and hold up well during extreme weather.
This project is supported by the Metropolitan Council as part of our collaboration to reduce water use on Twin Cities lawns.