Regular lawn mowing helps keep your lawn looking its best. For the healthiest lawn, cut only one-third the length of the grass blade each time you mow. This leaves enough blade for photosynthesis and not so much that the lawn appears ragged. Mowing produces grass clippings, which decompose to provide nutrients for your lawn. Both regular lawn mower blades and mulching blades produce grass clippings, but the clippings are different depending on the type of blade.
Regular lawn mower blades cut the grass with one stroke. The rotary action of the turning blade blows the whole grass clipping out the side of the mower or into a grass catcher bag. A mulching blade curves, so it cuts the blade of grass once. Then it throws the cut piece back into the blade to be cut several more times. This results in many small pieces of grass instead of the single grass blade.
Lawn mower blades of all types work best when sharp. Dull blades tear and shred the grass, resulting in a ragged-looking lawn and irregular chunks of cut grass. Sharpen both regular and mulching blades with a metal file or sharpening stone. Follow the curve of the blade and maintain about a 40-degree angle between the sharpening file and the blade's edge. Keep the blade balanced and don't bend it. Sharpen blades at least twice every mowing season, or whenever you notice them becoming dull.
If you routinely bag your grass clippings, you don't need a mulching blade. Cut grass can be added to compost piles or used as one of the layers in a lasagna-style raised bed garden, where layered organic matter serves as both soil and mulch. If you like to leave your grass clippings on the lawn, pieces left by a mulching blade decompose more quickly. Nutrients return to the soil faster than with grass cut with a non-mulching blade. Mulching the lawn with clippings this way may reduce the need for water and fertilizer. Mulch holds in moisture and returns nutrients to the soil.
Keeping your grass a little longer hides the scattered clippings better. How long grass should be depends on the type of grass. Cut your grass in stages if you've let mowing go so long that so you need to cut more than one-third of the grass blade to get the height you desire. Set the mower to cut about half the extra length the first pass. Then lower the blade and cut again. Your mulching blade can do a better job of leaving small, uniform pieces with this method. If the clippings get too thick, rake and bag them one time instead.