How about:

If you REALLY don't want to use Roundup:

Cut everything down

Rotavate

Put manure on the top (Rotavate it in is better, but only if you can get some in time)

Cover with mulching plastic

When you are ready to plant (e.g. in the Spring) just plant straight through the mulch - that will give you a further N months of mulch to kill the remaining weeds