Inside the polytunnel as of today, no cover crop as the water to the allotment is turned off for the winter. So the next best thing is a mulch of compost covered with an opaque but permeable membrane which prevents weeds from growing but allows gas exchange. Underneath the soil is damp and there are plenty of worms. I doubt it'll freeze over even if it gets really cold outside. I am concerned that it'll be a cosy place for rats and mice to spend the winter - we'll see in a few weeks time when I get some samples for the first soil test of the year.
Here's the first soil test of the year, and though not perfect I'm still quite pleased with it. The main thing for me is the pH 6.7 which must be a payoff for all the OM and S that's been added these past few years. I'll continue to monitor it but I don't think there's any amendments necessary. I'll dig in a load of perlite and/or vermiculite in the spring and that's about it.
Root nodules containing N fixing bacteria in some field beans that we're growing as green manure on the allotment over winter. When spring comes and/or before flowering, I'll strim the plants to ground level and till everything into the ground.