A Dummies Guide to Mowing

It's easy right? Just fill 'er up with gas and cut that grass! Mowing does not exactly seem like a science, and except for your dad telling you to overlap your mowing rows so as not to leave any stragglers behind, not much instruction is passed on from one generation to the next when it comes to mowing. Here are a few tips that our dads may or may not have left out of our lawn mowing initiation.

Selecting a Mower Type
The two primary types of mower on the market are rotary mowers and reel mowers. The rotary mower certainly wins out in the residential market whereas gasoline powered reel mowers are more widely used in professional settings like athletic fields and golf courses. Besides the method of cutting, the primary difference between the two mower types is the quality of cut, with the higher quality going to reel mowers. Even though reel mowers provide a higher quality of cut they require more maintenance and are harder to adjust which is why they are typically left to the professionals. If there is a mixture of weeds in the grass, the reel mower may have some trouble cutting them if they get too tall. For typical home use, I would recommend purchasing a rotary mower.                              

Mowing Height
Why does mowing height even matter? When we mow, it is like cutting off a plants head or arm or leg, or however else you want to look at it. The bottom line is that we are removing a part of the plant that was originally useful to it and we are essentially injuring it. The portion of the grass blade that is removed is a loss in photosynthetic potential as well as stored carbohydrates for the plant. This reduction in photosynthetic potential and carbohydrates consequently affects the root growth below ground. Taller grass equals a larger root system. Shorter grass equals a smaller shallower root system. This becomes very important when it comes to water availability in the soil, especially during drought conditions. The deeper the roots can go, the more water they will have available to them. the grass also serves to shade the soil, this shading affect reduces weed seed germination. Therefore if grass is cut too short it could encourage weed growth because of reduced shading. And as can be seen in the table below, some grasses simply have a preferred height of cut based on field research. 

Table 1. Recommended Mowing Heights for Lawn Grasses
Turfgrass	Cutting Height in Inches	Mowing Frequency
Cool-season
Kentucky bluegrass	Winter: 1.5 to 2.5	High
	Summer: 2.5 to 3
Fine fescue	Winter: 1.5 to 2.5	High
	Summer: 2.5 to 3
Tall fescue	Winter: 2 to 3	High
	Summer: 3 to 3.5
Ryegrass	Winter: 1 to 2.5	Medium
Warm-season
Common bermudagrass	1 to 2	Medium High
Hybrid bermudagrass	0.5 to 1.5	Very High
Carpetgrass	1.5 to 2	Low
Centipedegrass	1.5 to 2	Low
St. Augustinegrass	2.5 to 4	Medium to High
Zoysiagrass	1 to 2	Low to Medium

Source: Clemson Cooperative Extension: Mowing Lawns
Mowing Frequency

A general rule when it comes to mowing frequency is to only remove 1/3 of the leaf blade when mowing. For example if the grass is 3" tall you should only mow it to 2" tall, removing 1" of the grass blade. You can also calculate this in reverse order. If you have St. Augustine grass and you want to maintain it at 4" tall you should cut it when it reaches 6" tall in order to remove only 1/3 of the leaf blade. Following this rule will minimize stress on the grass. In reality are you going to go out with a tape measure to the grass? No. But this is a useful principle that can be determined pretty accurately with the eyeball test.

Mulching Vs. Bagging
It is easy to think that because the lawnmower comes with a mulch bag that it is proper procedure to collect the leaf clippings while mowing. This however is incorrect. By mulching (allowing the grass clippings to return to the soil) the nutrients from the leaf clippings are recycled back into the soil and taken up again by the grass. The only scenario that I would advise collecting leaf clippings is if the 1/3 rule mentioned above has not been followed and you are getting a significant buildup of clippings on top of the grass. This buildup can kill the grass underneath it if significant enough. Either bag the clippings while mowing or come back afterwards and use a rake or blower to spread them out.
Blade Maintenance
The lawnmower blade should be sharpened every spring and possibly more often depending on how much use it gets. A sharp blade produces a cleaner cut of grass that will not fray and turn brown at the tips.

Final Odds and Ends to Consider

It is best to cut grass when it is dry. This will reduce the amount of clumping of grass clippings and clogging of the mower. Try to avoid scalping the grass which often happens on uneven ground. Scalping is when the mower blade gouges into the grass, cutting one section very short or even into the soil. Final instructions: have fun! Mowing is a blast!

Grass Roots Initiative

How much do you like grass? Well, if you like it a lot, entering into the "Grass Roots" exhibit, opening October 16th at the U.S. Arboretum in Washington DC, could be likened to entering a wonderland of grass. If grass brings up bad memories of countless hours spent mowing your five acre lawn with a push mower when you were nine years old than you may want to avoid this attraction when you make a visit to the U.S. Arboretum. One thing I can guarantee however, is that whether you really like grass or hate its' guts, this new exhibit will prove to be extremely educational and interesting to all.

The Grass Roots exhibit hosted at the arboretum is part of a larger scale project called the "Grass Roots Initiative" which is a collaborative effort by U.S. Arboretum (run by the USDA Agricultural Research Service) and the National Turfgrass Federation (NTF). The purpose of this initiative is to increase the awareness of the importance of turfgrass to the environment and our society, demonstrate new technologies that improve maintenance practices, address and update national turfgrass research priorities, and have an impact on policymaking by bringing policymakers together on the topic of turfgrass. For the average homeowner, the Grass Roots exhibit is sure to be a very comprehensive and interactive experience with turfgrass. It should be very practical, to the point where information learned at the exhibit can be taken back home and used in the home lawn.

The 10 exhibits that will be on display at the U.S Arboretum include:

•  A golf display featuring a USGA green, a tee, and a fairway
•  A sports field featuring a comparison of natural grass and artificial surface
•  A lawn display featuring seven species of warm-season turf and six species of cool-season turf
•  A Kentucky blue-grass mowing “demonstration” area and information about proper mowing techniques
•  A “History of the Lawn” walk
•  A rain garden with grasses demonstrating grasses’ ability to absorb water and filter nutrients
•  A display featuring USDA research on poverty oat grass (Danthonia spicata)
•  A fertilizer display
•  An irrigation element showing common components of irrigation systems and an interactive   irrigation pressure demonstration
• And agricultural grass crop displays which will include a display of how perennial ryegrass is grown for seed production

 In addition to the physical exhibits, the initiative will potentially include a symposium on turfgrass sustainability and resource efficiency, numerous workshops, public policy forums, and demonstrations as well as updating scientifically vetted content on its website.

If I have a chance to visit this exhibit during its duration I will not pass it up. I'm sure that discussions and debates will be stimulated as to whether you agree or disagree with the information provided by this initiative which I believe is healthy. As a student studying turfgrass culture it is important to be aware of the current events happening in the industry such as the Grass Roots Initiative. To those who are homeowners seeking to manage their lawns with excellence, it is also good to know about these opportunities for fun and interactive education!


Sources:
The Grass Root Initiative: A Science-Based Focus on Turgrass
Grass Roots Main Webpage
Grass Roots Initiative Launched at the National Arboretum