My VPI junior doesn't have aground lead

Turntable has no ground lead but the tonearm cable has one doesn't it? However the arm may not have electrical continuity to the plinth where the bearing carrier is mounted; my MK 4 doesn't.
I ground the bearing carrier (which grounds the platter via spindle contact) with a separate small stranded ground lead which is crimped to a ring-tonge lug, which is fastened underneath one of the bearing carrier bolts/nuts. Ground that to the same place you ground the tonearm, typically at the phono stage or preamp's grounding stud on the back.

If your not experienceing and RF hum don't worry. If you are then try finding a chassis ground that will minimize the hum.

What arm do you have?
If it is Rega arms, it is normal not having ground lead.