It's incredibly easy to avoid landfilling grass clippings while at the same time reaping the happy side effects of doing less work, saving on water usage, paying less for lawn maintenance and getting a healthier lawn! The secret is to leave the clippings on the lawn, or to "grasscycle."
Here's how: Every time you cut the grass, follow the "one third" rule. Mow often enough to cut only one-third of the length of the grass blade in any one mowing. This strengthens the grass plant by reducing shock to the lawn's root system and creates a denser, healthier root system. Once you've mowed, let the clippings go to work. By leaving them on the lawn, you'll reduce your need for fertilizer. Grass clippings are 80-85% water and contain 2-4% nitrogen, phosphorus, potassium and other nutrients. According to the University of Colorado, grasscycling can reduce fertilization needs by 25 percent or more. You'll also see your water bill shrink because grasscycling provides an umbrella for your grass roots and keeps our harsh Wyoming sun from drying them out. And of course you'll save your back and time since there'll be no raking and bagging.
Some worry that leaving grass clippings on the lawn will cause thatch, but thatch is an accumulation of the "woody" parts of the grass plant (stems and roots), not the clippings. Thatch is most often caused by over-watering and over-fertilizing. Grasscycling can actually make your lawn look healthier; many golf courses and parks have been grasscycling for years. Plus, you don't need a mulching mower; any mower will work if you simply remove the collection bag. Many mower manufacturers will sell mulching blades and adapter kits, which can improve your mower's grasscycling performance. You'll get your best grasscycling results when you mow more often and only when your lawn is dry.
The EPA offers additional information on its GreenScapes website.