Remove the vinca starts from their pots, and shake off excess dirt. Check the roots for any damage, and prune any dark or discolored material off the base.
Fill a pot with a half-and-half mixture of potting soil and compost. The compost will increase the tilth of the potting medium and accentuate the drainage. Dig a hole just deep enough for the vinca root ball. Place the vinca starts at least six to eight inches apart at the edges of the pot so that they will trail over the edge. Fill in around the roots, and press the soil in to compress.
Water the pot until it leaches moisture out the drainage holes. This will settle the soil. Add more soil if necessary to bring the level to just under the lip of the pot. Keep the pot evenly moist, and place it in a semishady area for best growth.
Prune the vinca as it gets too long and drags on the ground.
Fertilize perennial vinca in spring just before new growth begins. Use the amount recommended for the size of pot you have. Mix it with water, and add the mixture to the soil.