Question

How many frost free day is require to grow cotton crop?

Answer 1

About 160 days.

Explanation:

All about cotton:
http://www.cotton.org/tech/ace/growth-and-development.cfm

http://cotton.tamu.edu/General%20Production/Georgia%20Cotton%20Growth%20and%20Development%20B1252-1.pdf

Water is also an important component in cotton growth!
http://www.cottoninc.com/fiber/AgriculturalDisciplines/Engineering/Irrigation-Management/Cotton-Water-Requirements/