The question has been asked of me if the kind of hemp you find in typical craft stores makes and acceptable string. Well, the answer is depends.
The best kind of hemp you will find for making strings, will be coarse and not waxed, the craft store walmart crap may not do very well from my own personal experince, but others seem to think it works ok, after all hemp is hemp right ?
The hemp you should used should be tested before use, pull on the a single strand, how easily does it break ?
Hemp strings can last a very long time and work very well, but they come with a risk, and require a level of respect. You must make sure any string you make from hemp to be flaw free, and your bow never be overdrawn.
Hemp is the strongest plant fiber on earth, it works great for bow strings and has been used and trusted in many situations.