What can I use as green manure?

figrat

I've been using green manures rather erratically for the last couple of years - mainly phacelia and mustard. I'm just about to clear one of my veg beds for this year's crop. At the moment, it's got a couple of fading purple sprouting broccoli, a zillion forget me nots and and land cress which is just about to run to seed.

I'm wondering what your thoughts are on digging in the landcress as a green manure? Happy to put rest of it on compost heap, but thought the landcress might be a quick fix if I dug it straight in.

My soil is very light and free draining.

Green Magpie

Doesn't landcress have long, fleshy tap roots? I think they might take a long time to rot down. Mine is going to seed now but I think it's bound for the compost heap.