I would argue that everything grown on the veg garden is a potential green manure and as much none weed vegetation should be grown as possible throughout the year. Rather eccentrically I let things like coriander and rocket seed themselves in the rows. You might be horrified to see my broad bean tops shredded (with my hedge trimmer) on the surface at the present time. If it really does encourage the slugs I am perfectly happy for them to eat their favourite food, decaying vegetation.
http://www.nodiggardener.co.uk/2012/07/why-gardeners-dig-part-1.html
