Spread a tarp under the muscadine grapevines once the grapes begin to drop. Check on the grapes periodically once they deepen in color so that you can plan appropriately.
Wear gardening gloves to protect your hands. Grab one of the grapevines, and shake it gently. The ripe grapes will fall from the vine, and the unripe ones will remain on the vine.
Grab each corner of the tarp, and bring the corners together in the middle. Move the tarp to transport the grapes. Inspect the grapes for inadequacies, and remove any grapes that have cracked skin or discoloration.
Harvest the grapes until the end of October when the harvesting season ends. Check on the grapes every day, and place the tarp under the vines when the grapes begin to fall.