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Preparing Your Houseplants for Winter Indoors

Lesson 1: Repot root-bound plants

I often hear home gardeners say their plants are pot bound. I have never seen a bound pot, but I have seen many root-bound plants.

As you move houseplants in for the winter, examine the root balls to see if your plants are root-bound. To see the root ball, you need to knock it out of its container. Hold the plant in its container with your fingers on each side of the stem and turn it upside down. Rap the top edge of the container sharply on the edge of a solid table or bench, and the root ball will dislodge. If it is covered with a solid mat of roots, the plant is root-bound.

To stimulate root-bound plants to produce new roots, take a sharp knife and make four or five cuts through the root mat from the top to the bottom of the root ball. Using your fingers, loosen as many roots as possible and shake out old rooting medium from the center of the ball.

If possible, select a larger diameter container to transplant into. If using a larger container is not feasible, then you must apply the bonsai root-pruning practice, cutting out one-third of the root mat to allow new roots room to grow.

When repotting the plant, always use freshly blended potting medium. Discard all the old rooting medium in your compost pile. Freshly blended potting medium that has been kept moist is biologically active. Old potting soil that has been allowed to dry out and remain bone dry for months is biologically dead. To make old dried-out potting medium usable, moisten and blend it with either fresh compost or new potting medium.

To repot a plant, always place some fresh potting medium in the bottom of the container. Leave a half-inch free space between the top of the root ball and the top edge of the container for proper watering. Finally, bounce the bottom of the container sharply on the hard surface so that the loose potting medium fills in the voids.

As soon as you finish potting, flood the surface with water several times until you see excess water flow from the bottom of the container.

Bay Gardener’s Potting Soil Recipe

Mix equal parts by volume garden soil, compost from your garden or commercial compost and perlite. Place in a microwaveable container and microwave at full power for 15 minutes for each gallon of potting soil. Cool before using. Store the unused rooting medium in a plastic bag so that it will remain moist.