The nights are now longer than the days, the air is slowly becoming cooler, and bits of color are emerging.  Autumn is here, and with it the splendors of nature go into a bold array of reds, oranges, yellows and browns.  This ephemeral time of year is often enjoyed with breathtaking drives through the countryside, pleasant walks through parks, or just sitting with a cup of tea while soaking in the vibrant view out your window.  And then those ebullient leaves fall onto your lawn.  Oh dear, now what?

 

Layers of wet leaves and snow can be problematic for lawn health, so we have been taught to collect, bag and dispose of the leaves.  Not many of us manually rake our yards anymore.  Instead, we often prefer the easier and less labor-intensive choice of using leaf blowers—all you have to do is point and blow.  But are leaf blowers and leaf disposal the best option for us, our yards, and our environment?

 

Many leaf blowers are gasoline powered and typically use a two-stroke engine.  Two-stroke engines are light weight, cheap, compact, and easy to produce, making them ideal for use in our yard equipment.  However, two-stroke engines do not have an independent lubricating system, thus oil and gas are mixed.  About 30% of the fuel does not combust fully, and as a result the equipment emits large amounts of pollutants; such as nitrous oxides, carbon monoxide, hydrocarbons, and other toxic substances (1,4).  You are directly breathing in these emissions when you are using your gas-powered leaf blower (or other gas-powered lawn or yard management equipment). 

 

The deleterious health effects of breathing nitrous oxides, carbon monoxide and hydrocarbons are well documented and quite alarming, and I highly encourage you to do your own research into it.  In fact, the EPA implores medical, scientific and government agencies to increase public awareness to the dangers of two-stroke engine exhaust, and to create legislation to protect the public (1).  It is also important to acknowledge that two-stroke engine emissions significantly contribute to environmental problems.  Two-stroke engine emissions are well known to add considerably to smog formation and acid rain, and it is estimated that in California gas-powered lawn equipment produces more ozone pollution than all cars in the state (5).  Gasoline powered lawn and garden equipment nationally represent almost 4% of all VOC emissions and 12% of all CO2 emissions (1).

How can we positively shift this situation so we are not breathing in deadly toxins and contributing to global pollution? Well, an easy fix could be to just use electric powered leaf blowers to collect our leaves and bag them, especially if you purchase your electricity from renewable energy companies.  However, although I am a huge proponent of electric equipment when any lawn equipment is needed, might there be an even better option than using leaf blowers to manage our fallen autumnal leaves for collection and disposal?

 

The EPA estimates that in 2018, landfills received about 10.5 million tons of yard trimmings and leaves, and 2.6 million tons were combusted (6).  There is no need to send all of these leaves into our landfills, or as particulate matter into our skies.  The solution is simple.  Get out your lawnmower (electric please!) and mulch your leaves where they lay on your yard.

 

Apart from keeping your leaves from ending up in landfills or incinerators, mulching your leaves into your lawn creates two great lawncare benefits—nutrition and weed control for your lawn.  Research shows that the Fall is the best time to fertilize your lawn, and that fall fertilization often eliminates the need to fertilize in the spring (2,3).  Perfect!  Your trees are providing you with free nutrient rich fertilizer.  Decomposing mulched leaves enhances your grass quality and reduces fertilizer costs (3).

 

Another great benefit is zero weeds!  The mulched leaves cover up bare spots in your lawn, and thus subdue weed seed germination.  It has been shown that with only 3 years of mulching leaves into a lawn, an almost 100% reduction of dandelions and crabgrass can be achieved (3).  You can also collect mulched leaves in your mower bag and use it for mulching in landscape beds and vegetable gardens.

 

So how do you mulch your leaves?  When the leaves are dry simply run over them with your lawnmower.  Mulching mowers are a great tool, but regular mowers work fine too (and again, I’m plugging for electric mowers—pardon the pun—instead of gas-powered mowers).  Once a week (or twice if very windy), set your mower to the highest setting and cross over the leaves once or twice.  Up to 6 inches of leaves can be mowed at one time (depending on your mower).  The chopped-up leaf litter will only be visible for a few days as the leaf pieces slip between the grass blades and down to the soil surface to decompose (3).

 

So put away those leaf blowers and mulch your leaves into your yard.  Not only do you save the effort of bagging, help the environment, and avoid breathing in toxic emissions if using an electric mower, but you are also doing a great service to your lawn by providing it with nutrient rich fertilizer and suppressing weed growth.  It is a win-win all around.

 

 

1) Banks, Jamie and Robert McConnell, National Emissions from Lawn and Garden Equipment, United States Environmental Protections Agency, Retrieved Sept 30, 2021 from https://www.epa.gov/sites/default/files/2015-09/documents/banks.pdf

 

2) Brewer, L. J. (n.d.). Lawn Care: The Easiest Steps To An Attractive Environmental Asset. Cornell University. Retrieved March 23, 2021, from http://hort.cornell.edu/turf/lawn-care.pdf

 

3) Finneran, Rebecca, Smart Gardeners Mulch Fallen Leaves into Lawn to Save Money, Michigan State University Extension, Jan 24, 2013, Retrieved Sept 30, 2021 from https://www.canr.msu.edu/news/smart_gardeners_mulch_fallen_leaves_into_lawn_to_save_money

 

4) Palmer, Brian, How Bad for the Environment are Gas-Powered leaf Blowers?, The Washington Post, Sept 16, 2013, Retrieved Sept 28, 2021 from https://www.washingtonpost.com/national/health-science/how-bad-for-the-environment-are-gas-powered-leaf-blowers/2013/09/16/8eed7b9a-18bb-11e3-a628-7e6dde8f889d_story.html

 

5) Son, Jiahn, Lawn Maintenance and Climate Change, Princeton Student Climate Initiative, May 12, 2020, Retrieved Sept 28, 2021 from https://psci.princeton.edu/tips/2020/5/11/law-maintenance-and-climate-change

 

6) United States Environmental Protections Agency, Yard trimmings: Material Specific Data, Retrieved Sept 30, 2021 from https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/yard-trimmings-material-specific-data, accessed 9/30/21.