"F Murtz" wrote in message
...
Can I mix grass killed a month ago with roundup into soil With tiller.

Yes if the tiller is strong enough.

What to do with fresh sawdust, I have a lot, if it can not be used fresh
how do you rot it quickest.

Pee on it regularly (the ammonia in your pee willl help it rot) or put it
in a chook pen and let the chooks turn it to great soil improvering stuff or
add lots of manure and give it a stir reguarly.

If the new bed has 6" of green grass on it do I mow it first and remove or
just run the cultivator tiller over the lot (and the aforementioned
roundupped dead grass from elsewhere.Or roundup the new bed, wait a week
or two then cultivate ?

I'd remove the grass first and tehn dig it over with a fork but you could
kill it and then till it or you could till it and then keep weeding and
working on it till it gets to the condition you want. There are no hard and
fast rules just what works for you in your situation.