Ken you are right, I play down green manures partly as counter-balance to the massive over-simplification that is out there.
They are often sown without realisation of how long it takes to kill them in spring, by mulching as John says.
This increases slug numbers.
However for those with insufficient compost, and plenty of space, they are an option.
Though I reckon it’s cheaper + quicker to buy more compost and increase the veg output proportionately.
