Determine which plants are root-bound. Plants that are full size and recently purchased are usually root-bound if they are sold in their original plastic growing pot.
Gather the necessary supplies needed to complete the project.
Prepare a work station. If indoors, cover the floor or a table with newspaper or a drop cloth as this project will be messy. If outdoors, consider working in the grass as you should not need to clean up spilled soil off the grass.
Put on your gardening gloves and fill the larger pot about half full with moist potting soil.
Wrap your hand around the bottom stems of the root-bound plant.
Slowly turn the plant over while cradling the bottom of the plant in your hand. The plant should slide out of the old pot into your hand. You may have to twist or shake the pot gently to loosen it from the plant.
Keep the plant in one hand. With your other hand make 1/4 inch deep incisions along the edges of the root ball of the plant with the utility knife in a criss-cross pattern.
Gently separate the roots of the plant where you made the incisions. Only the roots around the edge of the root ball should be separated. Separating the roots will encourage them to grow into the new soil.
Turn the plant upright and place the root ball into the soil of the new pot. The top of the root ball should be about one half inch from the top of the new pot.
Pack more moist soil around the root ball until it can stand upright in the new pot.
Add water to the plant if necessary.