Possible Clues:

• Turn in
• Get some shuteye
• Go to bed
• Retire to bed (informal)
• Box the fodder and go to bed
• Lambaste article written by grass (retired)
• Retire
• Crash impact something that's cut and dried
• Turn in, perhaps using items hidden in 17-, 24-, 48- and 57-Across
• Go to bed (informal)