No Mow May in Full Swing………So what’s wrong with ‘No Mow May’?

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No Mow May in Full Swing………So what’s wrong with ‘No Mow May’?


by Dr. Edward Nangle, Dr. David Gardner, and Thomas deHaas


Lawns are greening up and growing like crazy. You may be tempted to employ the technique titled ‘No Mow May’. But what’s wrong with letting your lawn grow for the whole month of May without cutting it?








If you are concerned about the health of your lawn, there’s potentially some downsides to ‘No Mow May’.








No Mow May originated in the United Kingdom as a way to support pollinators. Many of the weeds in our lawns like clover and dandelion are a source of pollen for bees and other insects.









The idea was that if we let our lawns grow without mowing, the weeds will provide pollen.









Of course, by definition a weed is a plant growing where it is not wanted and so in that regard beauty is in the eye of the beholder.









City ordinances may also have an impact on this statement too.








Further to this the only piece of research that was published regarding the initiative was retracted due to data issues and thus we are in a quandary as to the efficacy of the approach as compared to flowering trees in the landscape.








With regards to dandelions in particular, Dr. David Gardner, Horticulture Professor for The Ohio State University main campus states,


“In Ohio, dandelion peak bloom is April, clover peak bloom is late May into June.  Peak grass growth is May.  To me it almost makes more sense to tell folks not to mow in April or June or both and properly mow to ensure turf density in May.  The weeds that peak in May for bloom are some of the winter annuals, like Veronica, but also ivy and violet and these are not the weeds we necessarily want to give an agronomic advantage.”









But not mowing for the whole month of May will mean your lawn may be approaching a height of 12-24 inches depending on species and climatic conditions. If the lawn is mowed down to a recommend height of 3” the first of June, the lawn may go into shock, the crown will be exposed and as we get into the drier months of summer, the grass plants may suffer and even die. Reseeding might be necessary in September to bring back the turf which will cost time, money and effort.









Dr. Edward Nangle, Turf Specialist for The Ohio State University, says,  “While there is an understanding of the potential for this idea, there is concern that a lawn cannot be returned to previous conditions and thus will homeowners accept the new norm – we don’t know. Further to this if voids are created opportunities for soil erosion and weed encroachment will occur – again will homeowners accept this and is there a potential concern regarding water pollution with soil erosion potentially increasing?”


Currently a combined effort between the OSU CFAES Wooster Campus and Columbus campus is focused on the impacts of the process on lawn conditions both on traditionally maintained lawn type surfaces and a lower input situation (Pic 1a and 1b) and updates will be provided via Turf Team Times and other outlets that the OSU Turfgrass Team uses including social media.



Figure 1a - Photo provided by Dr. Edward Nangle





Figure 1b - Photo provided by Dr. Edward Nangle




This topic was briefly discussed at minute time stamp 11:00-15:30 in a recent ‘Turfgrass Team Times’ recording that is produced by the turf team at OSU. The link of the recording is found below:


Research continues on the concept of ‘No Mow May’.


So, what about the pollinators? Actually, the pollinators are smart enough to find a smorgasbord of flowering plants during the month of May.









During a recent visit to a Christmas Tree Farm, the Pollinators where so prolific in the crabapple above, you could hear them foraging.








Take a look outside. There is a ton of pollen available. Ask anyone allergic to pollen.







With regards to a healthy lawn, a recommendation is to mow at a blade height of around 3” and not to remove more than a third of the blade.


3 inches





This means you may be mowing every 4 or 5 days in May. But don’t worry, the grass will slow its growth throughout the summer months. Actually our ‘Cool Season’ grasses go into a state of no or slow growth in the hottest part of the summer. You may go 2 weeks without mowing.


I know you are thinking if you cut your lawn short, say 2 inches, it really looks kept.


2 inches





My neighbor cuts his grass every 2 – 3 days. But he also has an irrigation system and dumps a ton of fertilizer on his lawn.









The temptation is to make our turf look like a golf course.








For most homeowners, this is not practical or cost effective.



So, what’s a homeowner to do?


  • Mow at a height of around 3 to 3 1/2 inches


  • Don’t remove more than a third of the blade.


  • Perennial weed control is most effectively done in the fall.


  • Reseeding is most effective in early September when soil temperatures and moisture are high.


  • Don’t remove grass clipping. Mulching them returns Nitrogen to the turf.


  • Fertilize sparingly and sweep or blow off any fertilizer on walks and driveways back into the turf.


So, although ‘No Mow May’ sounds like a good idea, there’s plenty of other pollen to go around!









See the following:


New Factsheet - Native Trees: Creating Living Landscapes for Birds, Butterflies, Bees and Other Beneficials:



Happy Mowing!