David J Bockman wrote:

The simplest way is to deliniate the area you wish to convert (I use garden
hose to play with the shape until it looks good) and then spray it with
Roundup. After 10 days or so, you can plant right in wherever you wish and
mulch/edge the space.

Dave

I agree completely; but I don't think you have to wait that long before
planting. The dead grass will break down into the soil if you bury it with
mulch or topsoil. You can dig it all in and add more compost next spring.

Best regards,
Bob