What if I don't have a Tulasi plant? Can I still worship Krishna?
Of course. Growing tulasi is not always possible, especially in colder areas where she has to be protected from the cold. Sometimes temples in northern climates keep a framed photograph of Tulasi on the altar if they aren't able to maintain actual plants. Krishna is very kind, and does not reject His devotees' worship on a technicality. At the same time, He is pleased when His devotees make an effort to do things—such as growing and maintaining tulasi plants—just for His pleasure.