Environmental Stress and Turfgrass Performance This Spring
(Updated: May 20, 2026, 12:09 p.m.)
Warm-Season Lawns
This spring has been odd indeed, as we are experiencing a record drought that began in September 2025. That has continued into spring, and even though we have had some warm temperatures, many turfgrasses are still struggling due to a lack of moisture and heat. When this is posted, I am sure some will say, "But it is 96°F today,” but those temperatures have been far from consistent. After reviewing almost three months of soil temperature data, it is clear that we are nowhere near optimal temperatures for the growth of warm-season grasses. Most warm-season grasses grow optimally when soil temperatures are between 75 and 85°F, and we have just recently eclipsed 75°F. Couple the lack of heat with limited soil moisture, and you get slow greenup of warm-season grasses. Yet my local golf course looks green. That is likely true, but their irrigation system is designed to be effective and efficient, resulting in improved greenup for them. The good news about the current environmental conditions is that turf pathogens are not happy either. Not many living things thrive under dramatic temperature swings and low moisture. For warm-season grasses, be patient as soil temperatures continue to rise and, hopefully, rainfall develops; these lawns will look great in no time.
Soil Temperatures in Raleigh, NC since March 1, 2026. The bold parallel green lines represent the ideal window for warm-season turfgrass growth.
Cool-Season Lawns
Tall fescue is also struggling due to a lack of moisture. If one has an irrigation system, the lawn is probably doing quite well. If not, there are likely dry spots and growth limitations due to insufficient rainfall. If one observes leaf spots or lesions, there is almost no chance of disease developing under the current moisture conditions. Remember, fungi need at least 8 hours of leaf wetness to initiate an infection, and even with irrigation, that is highly unlikely under our current conditions. With the lack of rainfall, we have also had very low relative humidity, which works against disease development in plants. Even with the recent uptick in temperatures, there is still plenty of time to start preventive fungicide applications in tall fescue lawns. Pathogens require time to grow, infect, colonize, and damage plants. Optimal conditions for brown patch and gray leaf spot are elevated temperatures and leaf wetness, and the latter has essentially been nonexistent. Be patient; if we start to get rain and humidity, those diseases will show up.
Soil Moisture Readings in Raleigh, NC since March 1, 2026
Golf Course Issues
We are still in the window for preventive fairy ring applications for both warm- and cool-season grass putting greens. We are also still within the window for preventive nematode suppression on both putting green grasses. We are almost outside the window for preventive Pythium root dysfunction (PRD) applications for creeping bentgrass in the Piedmont and the East. That window is probably in prime time for those in the mountains. Other than some PRD, we aren’t seeing much on creeping bentgrass putting greens. For bermudagrass putting greens, we have seen root-knot nematode and take-all root rot (TARR) symptoms. Root-knot nematodes are likely active now, and our research indicates a nematicide would be effective. For TARR, those pathogens are not active now; the damage that occurred in the fall is only now developing due to the lack of moisture and optimal temperatures for bermudagrass. If TARR pathogens were active, any fungicide applied for preventative fairy ring control should, of course, stop their activity, depending on the fungicide selected.
