Brandon Herlein wrote:
My yards has been taken over by weeds. I am thinking of killing it all off
with Round-up and starting from new. What is the best way, time, etc to
start a new lawn. I live in Iowa.

It's a great time to seed, but you'll have to move fast. Personally,
this late in the game (in Iowa -- I'm in Wisconsin), I'd go with a
remediation program. It's likely that the grass you have is just
stressed and with decent care and overseeding can recover. Ease off on
the mower height, put down some starter fertilizer, overseed, and
top-dress (topsoil, humus, mulch). Guaranteed this will help your lawn a
lot.

For full renovation, you may not want to put Roundup in the soil because
it will take a couple of weeks for it to dissipate. If you had more time
it would be OK as a first step. Till the weeds in, add peat or other
organics to the soil, overseed, topdress, water to keep moist for up to
two weeks then back off.

The weeds will come back, but not as strong, and you can do pre-emergent
and 2,4D broadleaf weedkiller applications next year to whack them once
the new grass is healthy.