No Mow May is a terrific idea as a way to promote awareness and habitat for emerging spring pollinators. However, refraining from mowing for a month may risk long-term damages to the lawn, which could result in extra costs, labor, and higher environmental impacts to recover from later in the summer. Residents and those who take care of lawns should consider the following to help prevent possible long-term lawn damage.

Long-Term Risks:

For most grass varieties don’t do well if more than 1/3 of the grass blade is cut at a time. Especially for conventional turf types such as Kentucky Bluegrass, cutting more than 1/3 of the blade damages key growth tissues in the blade of grass. When this happens, the grass spends the season recovering instead of growing or storing nutrients for winter.

This makes the grass more vulnerable to disease and less prepared to bounce back after drought or dormancy. If your grass is struggling in this way, it may require human intervention with fertilizers, extra watering, re-seeding, or other treatments to get it back to its former state.

Grass Clippings:

When No Mow May ends, there’s going to be a large amount of biomass to cut. At any time of year, it’s important to keep grass clippings on the lawn and off of paved surfaces. Despite seeming “natural”, grass clippings are an excessive nutrient that acts as a pollutant when it drains to a lake, creek, or wetland.

There is no treatment between the street and the receiving waterbody, and all that extra nutrient changes the aquatic community towards an unbalanced, turbid, pea-soup green state. When mowing for the first time after a long period of growth, it may be difficult to contain the grass clippings on the lawn, so be sure to plan for extra time to sweep up the clippings to keep those nutrients on the land and out of the water.

Additional Strategies to Implement:

• If you're mowing exceptionally long grass, mow in stages, starting as high as the mower can reach. Gradually lower the blade a few days later to reduce the shock and harm to the grass.
• Mow higher all year long - 3-4”. Taller grass blades in your lawn will help shade the soil surface, which helps reduce weed germination. Longer grass means deeper grass roots, which means the grass can store more nutrients and retain more moisture. Increased moisture retention and better soil cover create healthier soil, a more resilient yard that can withstand drought, resist weeds, and benefit the larger watershed.
• To build a lawn more conducive to Now Mow May, try integrating fine or tall fescues into your lawn, or explore switching to a lo-mow, no-mow, or bee lawn type of turf altogether. A bee lawn can blend grass with low-growing flowering plants such as such as clover, creeping thyme, and self heal, yet will maintain a thick, lush cover.
• If you’re supportive of a few dandelions but don’t want them to get too out of hand, yet still want to keep long standing vegetation, try mowing extra high to knock the seed heads off. Do this before the dandelions have gone to seed to help reduce seeds in your soil’s seed bank. If you choose to apply an herbicide for dandelions or other broadleaf plants, always follow the product instructions. Apply using spot-treatment versus blanket treatment to reduce drift and exposure to people and wildlife.
• Plan lawn treatments according to a professional soil test. This allows for the most relevant application, reduces excess, and creates the most efficient long-term result. Avoid weed-and-feed combination products as these increase excess product placement due to the difficulty of applying them according to what the lawn and soil need. 

More Resources:

Retain pollinator enthusiasm and practice water-friendly lawncare all year with these helpful resources. 

• Mowing, yard waste, and other water-friendly home tips
• VLAWMO cost-share landscape grants 
• Lawns to Legumes 
• Blue Thumb: Workshops, turf alternatives, and plant resources
• U of M Turfgrass Science
• Webinar: Drought Recovery for your Lawn