For reasons too lamentable to mention, I want t0 completely to renew my 60%-creeping-buttercup lawn. So I really need to get rid of every living thing there. Everything I read has spraying herbicides as step two 2 or 3. Probably illegal but anyway, not for me. A few "natural" sites say spraying with a powerful vinegar is an alternative. A myth: it does not have even the slightest effect on anything. I could buy turf but I doubt that one can simply place it over a bed of weeds and get good results. I guess I'll have to rototill the whole thing. But first - does anyone here have another suggestion?
Whatever you do, do not rototill buttercups! That will only encourage them to multiply as all the little bits and pieces will try to become individual new plants. Many years ago I planted a perfect little lawn in a space overgrown with buttercups. Since the area was so small and the digging relatively easy, I just dug it all up, shook off the roots of everything growing there - buttercups, grasses, other weeds then raked it more or less level and waited . . . waited until anything I missed would make its presence known so, over time, I could eliminate (almost) all the weeds. The problem with my method is that there are probably hundreds of weed seeds in the soil just waiting for their season to germinate. One way to suppress them is to put down turf rather than seeding with a lawn seed mix. Otherwise you will find fresh little weeds growing in your new lawn. If the grass is growing vigorously enough, it might choke the weeds out but I wouldn't count on it. I have 2 perfect little lawn areas these days - as much moss as grass but I like that look. To me, hand weeding is manageable and relaxing but I don't think the sort of lawn where no weeds grow is compatible with organic methods.
I had someone do something to both sides of my front lawn this spring. He actually dug up almost everything! !So I brought in two huge bags of soil, spread it, rolled it, put down grass seed... I mean, what is one to do when their long-planned retirement starts a month before the pandemic is declared? - but the seed did not take so I seeded and rolled again... and one side of my lawn is now perfecto. I go out with a magnifying glass and a comb quite often My wife is embarrassed and I know it can't last but it is currently great. The other side alas looks like a buttercup farm.
I had a buttercup problem area in my lawn quite a few years ago. I just turned the soil over with a digging fork, hoed it, raked it level, and sowed grass seed. I don't remember if many weeds/buttercups came up to compete with the grass, but they were manageable.