Should you collect grass clippings when you mow? No. It’s almost never a good idea to collect clippings from your lawn for several good reasons:
It’s true that for years it seemed like a good idea to bag grass clippings, but new research and environmental concerns have changed all that. Grass recycling now makes the best sense. Simply repeat this mantra before you mow: “Cut it high and let it lie.”
Clippings recycle as much as 15% of all the food value of the fertilizer applied. This means a lawn that recycles grass clippings will be greener and better fed than one where clippings are removed. And because grass clippings have a high water content, they break down quickly and return moisture and nutrients to the soil fast. Letting your clippings lie taps into the natural cycle of nature and saves you time and work.
Thatch is the layer of living and dead roots and stems that form on top of the soil. A small amount of thatch is a good thing, but when thatch builds up faster than the soil can break it down, all sorts of lawn problems start to crop up. The misunderstanding is that grass clippings add to this thatch. This isn’t true. Thatch is not composed of grass blades. Bagging the grass clippings does not reduce thatch buildup.
Besides the direct benefits of leaving your clippings to feed your lawn, there’s the additional environmental benefit of keeping clippings from filling up our shrinking landfills. Most people who bag their lawn clippings put them out for the trash collector. This “trash” is usually put in plastic bags that don’t decompose. The result is that as much as 10% of landfill space has been taken up just from grass clippings alone. We’re running out of space to dispose of our trash, so recycling clippings naturally makes great sense.