How to Encourage Root Growth in Leggy Plants

Lift the plant from the nursery pot. If the plant doesn't lift easily, squeeze the sides of the pot gently to loosen the root ball. For badly root-bound plants, cut the plastic pot from the roots with a utility knife.

Cut down the sides of the root ball with a clean knife. Make three to four vertical cuts spaced around the root ball. Slice through only the outer layer of roots, 1/4 to 1/2 inch into the root ball. These cuts loosen the bound roots and encourage new root growth after replanting.

Transplant the plant to a prepared garden bed or to a new pot. Use a pot with a diameter that's 2 inches wider than the existing root ball so the roots have room to spread and grow.

Plant at the same depth the plant was growing at previously -- with one exception. Tomatoes produce roots along their stems if you plant them deeper. Bury tomatoes to the base of their bottommost stems to encourage more root growth. Potatoes also produce new roots along buried portions of the stem.

Keep the plant in an area that receives sufficient sunlight, which varies among plant varieties. If you are growing the plants indoors in a window, rotate them every two to three days so the plant doesn't stretch in one direction toward the light.

Cut back the leggy stems by up to half their height with clean shears. Cutting back the plant encourages a fresh flush of new, fuller growth and allows the plant to expend more energy on forming healthy roots.