Don’t Let Your Houseplants Go to Pot

Question: I have several houseplants that I haven’t repotted since I bought them. They look like they may have outgrown their containers. How do I go about repotting them?

M.D., Irvine

Answer: Fortunately, houseplants are good sports about growing in the same pot year after year. Most have adapted to thrive in cramped quarters. As you have noticed, however, they all need to be moved to a larger pot at some point.

Symptoms of a pot-bound plant include roots coming out of the drainage holes, sluggish growth and water rushing right through the pot when you water.

If you are unsure if a plant needs repotting, remove it from the container and inspect the roots. The plant is not root-bound if you see mostly potting soil. But if you see plenty of tangled roots, it’s time to repot. Follow these guidelines.

* Choose a new pot. Select a container that is no more than one pot size larger, which translates to no more than 2 inches bigger in circumference. Generally, this means if your plant is in a 6-inch pot, the next size up would be an 8-inch pot, and so forth.

Don’t make the common error of repotting in a container that is too big. A bigger pot will not make a plant grow larger.

Instead of creating foliage, the plant will spend a lot of its energy trying to fill up the pot’s large root space. The empty potting soil can also become water-logged and might lead to root rot.

* Gently remove the plant from its old pot. If it does not come out easily, as happens with some pot-bound plants, hold the plant stem and soil surface steady with one hand and invert the pot with the other, tapping the pot rim against a hard surface.

If the plant refuses to budge, try running a sharp knife around the edge of the pot and then turning it over. At times for very pot-bound plants, it’s necessary to break or cut the pot to remove the plant.

* Loosen the roots before planting, which will stimulate the plant to reestablish itself.

If you will be repotting into the same size pot because of size limitations, you can get another two years or so out of the container by removing one-fourth of the roots all the way around the plant and any coiled or older roots at the bottom.

* Place enough soil in the bottom of the new pot so that when you set the plant inside it falls a half-inch to 1-inch below the pot rim. Carefully fill in the area between the plant and the side of the pot with a high-quality potting soil, gently tapping the entire pot two or three times as you fill it.

Continue adding soil until it is level with the root ball. Barely cover the rootball with soil and leave the stem completely exposed.

* Water the plant well with a watering can or by dunking the entire pot in water to soak the mix. Drain the pot and don’t water again until the first inch or so of potting soil has dried out. Overwatering can rot out the plant before it has a chance to establish itself.

If the soil is still wet, but the plant is wilting, mist with water. Most plants use less water when they are newly transplanted, so don’t be alarmed if your plant doesn’t need a drink for awhile.

* When moving a plant to a different location, give it a few days to adjust before placing it in its new home. Find a space that is similar to the prior location to avoid transplant shock.

* Wait to fertilize repotted plants for at least one month. The best time to feed is when you get a fair amount of new growth. This means the plant has successfully reestablished and needs nutrients for continued growth.

Have a problem in your yard? University of California Cooperative Extension (UCCE) Master Gardeners are here to help. These trained and certified horticultural volunteers are dedicated to extending research-based, scientifically accurate information to the public about home horticulture and pest management. They are involved with a variety of outreach programs, including the UCCE Master Garden hotline, which provides answers to specific questions. You can reach the hotline at (714) 708-1646 or send e-mail to ucmastergardeners@yahoo.com. Calls and e-mail are picked up daily and are generally returned within two to three days.