What is the origin of the phrase, "sleep tight?"

Here's your answer:

http://www.straightdope.com/columns/read/1570/whats-the-origin-of-the-expression-sleep-tight

+5

Beds used to have ropes or belts instead of bedframes, if those came loose, your butt hit the ground at night, thats why they used to say, sleep tight.

"Here in Cajun country where I live, before the days of mattresses, beds were square frames elevated from the ground, with ropes tied across in a sort of weave. It was similar to a hammock in concept. Anyway, in order to sleep well, the "mattress" couldn't sag, so the bed had to be "tight."

"For further insight I spoke to Dr. Jerry Lee Cross, a historian with the state of North Carolina. He confirms that the beds were, in fact, made of ropes tied across a frame. He adds that the origin of the phrase "sleep tight" is almost common knowledge among historians, simply because the modern bed is a little over a hundred years old."

bed straps on roman beds needs to be tied tightly to support matress and u i think

A long time ago, beds used to be just wooden frames with hooks along the frame to tie the mattress across the frame. The phrase "sleep tight" came from the hopes that the mattress wouldn't loosen and untie overnight.

I bow to the greater intelligence of the entomologists linked above, but I still like my interpretation. I figured it came from confirmed alcoholics who routinely got high as a kite and mighty tight before passing oot drunk, thus sleeping tight all right, but not in much shape for the bed-bug fight.