I have an old lawn that was neglected for years (very compacted). It has a myriad of undesireable weeds, grasses, clover, etc. I want to aerate and seed, but am unsure of whether I should roundup everything first. My experience has shown that if I spray broadleaf killer throughout the summer the grass will take off enough to look good until the August heat wave comes. My plan was to: 1. Mow it low 2. Aerate 3. Lay down seed 4. Add some starter fertilizer 5. Add compost and lightly rake Not sure if and when I should add pre-emergent to treat some of the existing weeds, grasses. Thanks for any input.