Chris Hogg wrote:

On Fri, 28 Aug 2015 11:33:00 -0500, "JIP" wrote:

Hello

I have today used a hired petrol lawn scarifier, having put down
mosskiller sometime before.

I now plan to overseed the lawn that remains.

I saw one website that said I should put down more mosskiller now,
because it can get at the remaining moss more effectively, and then
do the overseed.

Any thoughts on that - and if it's a good idea, can I do the
overseeding straight away or wait a while?

Thanks

I have no thoughts as to whether a second round of moss-killer is
needed; was that recommendation made by a moss-killer manufacturer?
They would say that, wouldn't they! But even if you do treat again,
unless you do something more fundamental to improve the soil, the moss
will return.

Moss likes moist, poorly drained and compacted soil. You need improve
the drainage and aerate the soil by spiking it and brushing in some
coarse sand. Don't be tempted to get a 'spiker' of any sort. IMO
they're useless. You can't beat spiking with an ordinary garden fork,
although it's hard work. Drive the fork in as far as you can,
preferably at least six inches, and wiggle it a bit, before moving on
about a foot and repeating. You should then spread a thin layer of
gritty sand over the lawn and brush it in, so that it fills the holes.

Thanks for the comment - what do you mean by "coarse sand" - is that
"builder's sand"? I understand that you can't use "lawn sand" on new
grass.