Posted: 05/04/2017 at 18:59
If you use a glyphosate weedkiller it will take 2 weeks for the active ingredients to work their way down to the roots and kill the weeds but some are very persistent and may come back and need a respray. It is not a good idea to rotavate live roots of couch grass, bindweed and so on as they just become so many little cuttings that grow into new plants.
Check your weed killer for the words glyphosate and systemic to make sure it does go down to the roots or you will end up with dead surface material, probably within days, but living roots that will re-grow.
Once you're sure it's dead you can rotavate the soil to prepare it for levelling and treading before either sowing seed or laying turf. You can hire a rotavator if you don't have one. Seed is cheaper but slower and is best done in April or September as that is when temperatures and rainfall are at their most favorable.
Whatever you do, don't hurry or skimp on the preparatory process, even if that means trying to sow in May or June. There's bound to be a cool patch that will do for sowing. Just avoid a heatwave and have a sprinkler handy in case it's dry.
Here's some advice from the RHS - https://www.rhs.org.uk/advice/profile?PID=424
Last edited: 05 April 2017 19:01:10