In message , Chris Hogg
writes
On Thu, 11 May 2017 13:37:49 -0700 (PDT), DICEGEORGE
wrote:

but surely if i mow a lawn without collecting the cut grass so the cut
grass lands on top of the grass then it rots down into the earth so no
chemicals are lost so it will grow forever?
george

That is the principle of a mulching mower. Chopping the clippings fine
in such a mower ensures they break down rapidly and disappear. Leaving
the clippings from an ordinary mower on the surface is generally
frowned on, and dire consequences are predicted, although just what
those consequences are, I'm not sure. I think a lot of them may just
be OWTs. I think clippings left on the lawn just look unsightly.

Persistent mulching might be OK if you vary the mowing route. For long,
narrow strips a mulching mower gathers the stuff into a strip where it
can damage the grass as it rots.


--
Tim Lamb