putting it to bed

When you finish a writing project or the copy for a newspaper or magazine, you say that you've "put it to bed". Cambridge Dictionaries agrees.

I have no idea of the origins of this term, but my guess would be something to do with the bed of a printing press.

Not much I write these days ever sees ink, but I still think of putting the magazine to bed when, after two months of work, a new edition of KnitNet is written and in the hands of the designers and programmers.

Then I usually put myself to bed, too.