Hi Jacquie
I would be tempted to add the green manure foliage to your compost bin. If you leave it in situ it could well attract a lot of slugs, particularly covered with plastic bags as they’ll love the dark and damp. This would not be a great start for your new brassica plants! I would cover with a layer of well rotted manure or compost instead and leave your green manure to rot down into lovely compost for use at a later date. Good luck
