Late winter to early spring is often considered prime houseplant-transplanting time. Maybe your plants are a little top heavy for their pots or you can see roots inching through the drainage holes. Whether you have been growing houseplants for years or are experimenting with your first one, there are a few lessons we can all keep in mind when transplanting and caring for our houseplants.

The most important thing to know when transplanting houseplants is that adding gravel to the bottom of the pot does not improve drainage. Water does not move readily from poorly drained material to well-drained material. The same goes for packing peanuts, pieces of broken clay pots, crushed aluminum cans, marbles, etc. If you would like a visual example, lay a sponge over a bed of gravel and water the sponge. Potting soil is very similar to a sponge in its water holding capacity and in its shrink/swell potential.

Before I go on, I understand that you may have been doing this for years and your plants are still alive. You have probably adapted your watering schedule to account for the heightened water table, and that is OK. But to grow the healthiest plants (which can better sustain insect and disease infestations), skip the gravel.

If you really want to add some material in the bottom of a very large pot to decrease the overall weight, please do so only with the understanding that you are raising the water table in the pot.

Back to potting soil: A good mix is another key to healthier plants. Several commercially available mixes are available, or you can make your own by mixing three parts sphagnum peat, one part vermiculite and one part perlite. Garden soil is not recommended for houseplants because it may contain root diseases and is often poorly drained in comparison to potting mixes.

There are a few exceptions to ideal potting mixes: Gardenias and other acid-loving plants may need more sphagnum peat in the mix. Some orchids are epiphytic and should be potted in a mix labeled for orchids. Cacti and succulents prefer even more drainage than most houseplants and will also grow better with mixes labeled specifically for them.

Selection of a new pot is also important. Look for pots that already have drainage holes or ones in which holes can easily be drilled. Plan to use a saucer underneath the pot to protect tables and floors, or plan on setting the plant in the sink or bathtub for watering.

If the plant you are transplanting is in a pot that is less than 10 inches across, move it into a pot that is only about one inch larger than the original. If the original pot is more than 10 inches in diameter, increase the pot size by 2 inches.

Gather the plant, the new pot, potting soil and a trowel or old serrated knife, and you are ready to transplant. Remove the old pot, use the knife to cut through pot-bound roots, and place the plant in the new pot. As you layer in the new potting soil, avoid pressing down hard and packing the soil with your fingers. Instead, tap the pot lightly on the table or floor a few times to help the soil settle. When complete, the soil level should be a half-inch to one-inch from the top of the container. The base of the plant should be at the same depth in the soil that it was in the old pot.

Water thoroughly, put the plant back in its happy place and enjoy!

— Jennifer Smith is the Douglas County Extension Agent-Horticulture for K-State Research & Extension. She can be reached at 843-7058 or smithjen@ksu.edu.