I missed this one last year.
I am often asked this same question, and I do not cover beds because compost has nutrients that are water insoluble.
I think others may disagree with this, as I often see it recommended to cover with polythene over winter.
But I reckon that nature would be struggling if nutrients wash away in winter!
From compost spread late autumn, I have always managed two bounteous harvests. That includes from a new planting in summer, after clearing the previous spring crop, and with no more compost added.
Another reason not to cover is built-up of slugs under polythene etc.
