When we first got our
mulching mower, I followed the advice of various websites and carefully
dried the clippings on a tarp before using them as mulch. Since
then, I've gotten sloppy, with no ill effects. My current mulch
method is to put the fresh clippings directly on the bed, like so:
I'm careful not to let them touch any plants, since fresh clippings can
heat up as they decompose. In about a week, they've all turned
brown and are mostly dry, though I noticed a bit of mildew on the
bottom layer (presumably the reason other gardeners prefer to dry the
clippings before applying them. Some urban flower gardeners have
complained about a bad smell as their glass clippings decompose.)
Six weeks later, the grass clippings have nearly disintegrated into the
soil. The quick decomposition of grass clippings is both their
upside --- they quickly feed your vegetable beds --- and their downside
--- they won't provide a long term weed barrier. I use the
clippings around annuals where I don't mind checking back at intervals
to make sure the beds are still weed-free.