Houseplants can’t run away from home, so be nice to them

“Extension on the Go” podcast by Debbie Johnson. Episode 95: Houseplants

COLUMBIA, Mo. – You might love your houseplants, but our homes often do not provide the best environment for them to thrive.

Houseplants plants need adequate light and humidity, two conditions often lacking in the average home, says David Trinklein, horticulture specialist for University of Missouri Extension.

“There are no houseplants in nature. Rather, we’ve arbitrarily gone out into the wild and selected plants that we think can survive in the austere conditions found in most homes,” Trinklein said.

Many houseplants are tropical and native to rain forests, an environment with high relative humidity. The humidity in our homes, especially during winter, is very low.

“The average home in the dead of winter has a lower relative humidity than the Sahara Desert,” Trinklein said.

To compensate, many people mist their houseplants. Trinklein says this is a waste of effort and water. To make a difference to the plants, you would need to mist them every 20 minutes.

“Mind you, this is 24/7 that you would, every 20 minutes, get out the mist bottle and mist your plants,” he said.

You can increase the humidity by installing a humidifier or placing the pots on trays filled with pebbles and water, Trinklein said.

Houseplants also need light. You may have a sunny window or two, but from the plant’s perspective there isn’t a lot of sunlight in our homes. Unless you’re willing to supplement with artificial plant light, you’ll need to choose species that can thrive, or at least survive, under the light conditions in your home.

“Unfortunately, the most colorful houseplants usually have very high light needs,” Trinklein said.

When we move to the long nights and short days of winter, light and humidity is especially low, so plants do little if any growing during this time. For this reason, Trinklein said, we should not apply fertilizer or plant food in the winter unless the plants are receiving artificial light. Your houseplants will also need less water since they’re in maintenance mode and not growing.

Proper watering is important for houseplants. Unfortunately, Trinklein said, we tend to kill our plants with kindness.

“Overwatering is the No. 1 cause of death in houseplants,” he said.

Because houseplants grow in containers, the roots will eventually outgrow the pot. But repotting houseplants too frequently is another way we often kill with kindness, Trinklein said. Any time you disturb a plant’s roots you cause it stress.

He suggests you wait until you see the plant growth slow down, and then gently check to see if the roots are circling the pot. If they are, you’ll need to untangle those roots before repotting. This will force the roots to reach out into new growing medium.

One mistake people often make when repotting their houseplants is compressing the new growing medium around the newly transplanted plant. Trinklein says that’s the worst thing you can do because it decreases the porosity of the growing medium, which causes it to retain water. This robs the roots of oxygen.

For those who seem to have bad luck when growing houseplants, Trinklein has a few suggestions. Snake plant, variegated Chinese evergreen and cast-iron plant can do well even in the most austere conditions.

“If you can’t grow a cast-iron plant, you might consider taking up another hobby,” Trinklein said.

For more information, see the MU Extension publication “Caring for Houseplants” (G6510), available for free download at extension.missouri.edu/p/G6510.