The most widely accepted origin of "sleep tight" takes us back to a time before the temperpedic foam and box springs. Until the early 20th century, the standard bed was a heavy wooden frame with a rope lattice strung tightly across it to support a mattress made of straw, feathers, or corn husks.
However, ropes stretch and loosen with use. A sagging mattress made for an uncomfortable, lumpy night’s sleep. The nightly ritual, therefore, included using a wooden tool called a “bed key” to tighten the ropes. The tighter the ropes, the firmer and more supportive the sleeping surface. So, to wish someone a good night’s sleep was literally to wish for their ropes to hold fast: “Sleep tight.” Sleep Tight
Whether for a partner, child, or friend, these variations add a personal touch to "Sleep Tight": For Partners: The most widely accepted origin of "sleep tight"
Keep your room cool (65–72°F) and dark to signal your body to produce melatonin. Consistency is Key: A sagging mattress made for an uncomfortable, lumpy
You don’t have to solve everything before morning. The world will rest too.