I'm watering with a hose or sprinkler real well when the ground dries out and only for the first summer. That's not watering. The few plants that survive after years of this watering are stunted and have no root system. Pull a soil analysis. If there are only mustards and other non-mycorrhizal weeds, that's part of it.
Compacted soils favor weeds.
That may be it. Your nose doesn't lie, if it smells offensive there is a reason. Round-up is much better than the weeds but everybody will kill at least one plant with it that you swear you didn't get. I cannot remember one time I've actually had to spray to correct anything other than weeds the first few years. If you did not figure it out, go through the list again.