Brian Miller, David Gardner, Alyssa Essman, & Tyler Carr 

Introduction 

Weeds, such as white clover, dandelion, crabgrass, and goosegrass, are major challenges in turfgrass management, competing with turfgrass for essential resources and reducing overall turfgrass quality. The short- and long-term impacts of autonomous mowing on weed dynamics and turfgrass competition are not well understood. Additionally, the use of autonomous mowers during turfgrass establishment and how it may differ from standard turfgrass management practices is not clear. There are two separate experiments, one evaluating perennial broadleaf weeds such as white clover and dandelion. The other experiment assesses summer annual grassy weeds such as crabgrass and goosegrass. 

The objective of these experiments is to evaluate the effects of autonomous and conventional rotary mowing practices on both perennial broadleaf and summer annual grassy weeds. 

Materials and Methods 

Two distinct experimental areas were selected at the Ohio Turfgrass Foundation Research & Education Facility in Columbus, Ohio to carry out the experiment. The areas were selected due to already having established weed species of interest. Both areas are a 2 × 2 randomized complete block design with 4 replications of each treatment combination.  

Factor 1: Mower type 

• Autonomous (550H EPOS, Husqvarna) 

• Conventional (HRN, Honda) 

Factor 2: Mowing height 

• 2.0 in  

• 3.5 in 

2 lb N 1000 ft-2 is applied to each experimental area, split between spring and fall 

*Autonomous areas are mowed every two days; clippings are not collected. Conventional areas are mowed to comply with the rule of thirds. Clippings are returned to the surface.  

Mowing began April 24, 2025, and treatments will continue through November 2025. The same treatments will be replicated from April 2026 through November 2026. 

• Turf quality is visually assessed once every two weeks to compare the differences between different heights of cut and frequencies. 

• The health and vigor of the turf is measured once every two weeks through using the normalized difference vegetation index (NDVI) to help eliminate bias and subjectiveness from the visual turf quality rating. 

• Turf density is visually assessed once every two weeks to compare the differences between different heights of cut and frequencies. 

• Shoot density is determined by manually counting the shoots from two randomly selected subsamples in order to assess treatment effects on turfgrass density.  

• Percent weed coverage is visually assed once every two weeks to compare the differences between heights of cut and frequencies.  

• Weeds of interest are counted once per month for the broadleaf weeds experimental area and once every two weeks for grassy weeds experimental area to track the population changes over the course of treatments. 

• A seedbank study is conducted once at treatment initiation and once at the end of each year to understand how the seedbank is affected by mowing practices. 

The project will be conducted for 2 growing seasons, ending in November of 2026. It is expected that through frequent autonomous mowing, turf density will increase, leading to reduced weed populations compared to conventional rotary mowing practices. We also hypothesize that autonomous mowing will suppress seedhead production in summer annual grassy weeds, such as crabgrass and goosegrass which may reduce the weed seedbank more effectively than conventional rotary mowing. Up to this point in the study, we have seen a reduced grassy weed population in the autonomously mowed areas at both 2 in and 3.5 in heights of cut.