"to put something to bed" usually means to conclude, solve, or finish something, as Bubb says. I assume that's what is meant here. It's a play on words: it's bedtime (the lights are out), and editor Warren has finished his business with the newspaper. See dictionary entries below.
keeblerelf, can I suggest you also look these terms up in a monolingual dictionary before you post here? People have posted a lot of dictionary entries for you in the last week for, eg, put to bed, tease out, carry on, show off. You could start with the dictionary and then if you don't understand the definition -- or don't know which definition applies to your sentence -- ask us if you've got the right definition. Here are some dictionaries to try:
https://www.macmillandictionary.com/
https://dictionary.cambridge.org/
https://www.oxfordlearnersdictionaries.com/
https://www.collinsdictionary.com/
https://www.merriam-webster.com/
https://dictionary.cambridge.org/dictionary/e...
put something to bed
idiom informal
to successfully deal with something or solve a problem:
We thought we'd put the issue to bed, but it was brought up again at the next meeting.
https://www.macmillandictionary.com/dictionar...
to finish dealing with something
I hope we can finally put this issue to bed.