Grass clippings in the lawn take around 2 weeks to 4 weeks to decompose in the lawn.
Most grass clippings will decompose in the lawn within a few weeks and if you compost grass in a pile and turn it regularly then it will turn into compost in a couple months.
It is good to spread grass clippings on the lawn as long as the grass clippings are not too long.
The grass clippings are a great source of nutrients for your lawn and the grass clippings will fertilize the lawn.
After mowing the best thing to do with cut grass after mowing is to leave the grass clippings on the lawn.
The grass clippings left on the lawn will work as natural fertilizer for the grass which helps the grass stay green and healthy.
However if the grass clippings are very long then they should be removed as the longer grass clippings left on the lawn take longer to decompose and could smother the grass below it.
But smaller grass clippings are safe to leave on the lawn.
As a general rule, grass clippings of an inch or less in length can be left on your lawn where they will filter down to the soil surface and decompose quickly.
Remove longer clippings because they can shade or smother grass beneath causing lawn damage.
Don't throw out bagged grass clippings as yard waste.
Cut your lawn to possibly the shortest height you have all season.
The ideal height is around 2 1/2 inches.
Cut it too low and the grass might not be long enough to photosynthesize and provide nutrients to the roots.
Too high and the frost might become matted after a snowfall.
Normally, weekly mowing is the rule, but some lawns need cutting more often.
Other lawns will grow more slowly and might need cutting only once every ten days or two weeks.
Generally, don't cut off more than one third of the grass blade.
As summer temperatures rise grass will grow more slowly and your mowing frequency will decrease.
During those hot summer days, leaving grass clippings behind creates a kind of mulch that helps maintain moisture in the soil.
If you leave short clippings on your lawn after mowing, they'll vanish within a few weeks.
And if you add your grass clippings to a carefully maintained compost pile, expect them to become a soil supplement in a few months.
Grass can seed itself if it is allowed to grow tall enough to produce stems and flowers.
Most lawn grasses that are mowed frequently do not get to produce any flowers and so do not seed themselves.
A few grass varieties, however, produce seeds from side shoots and will seed themselves even when mowed to a short height.