How long does my hair need to be to be transplanted?

There is no hair length requirement for having a hair transplant surgery.  If you are having a FUE donor hair harvesting, your donor hair needs to be 2 to 3 mm in length.

This depends on whether you are speaking of the donor or the recipient area and whether you are electing to have a transplant by FUE or FUT.  With regards to the donor area for FUE procedure the hair will need to be buzzed very short.  If you are having an FUT procedure the hair will need to be kept about and inch and a half long.  The recipient area can generally be kept at any length. 

For a strip graft, it doesn't matter.  For FUE, you want at least 1mm of hair.  If you currently shave, let it grow for a couple of weeks and go see a hair transplant surgeon in your area for recommendations.  Good luck!