January 27, 2021

Yard and Garden: Houseplant care during winter

AMES — Growing conditions for houseplants are less than ideal during the winter months.

Short days and long nights, low relative humidity and cold drafts can be stressful to many houseplants. Horticulture specialists with Iowa State University Extension and Outreach say that good consistent care should keep them healthy and attractive. To have additional questions answered contact Hortline at hortline@iastate.eduor 515-294-3108.

How often should I water houseplants in winter?

In general, houseplants require less frequent watering during the winter months than in spring and summer. Watering frequency depends upon the plant species, composition of the potting mix, environmental conditions (temperature, light and humidity) in the home and other factors. When watering houseplants, continue to apply water until water begins to flow out the bottoms of the pots. Discard the excess water.

Should houseplants be fertilized in winter?

Fertilization is generally not necessary during the winter months as most houseplants are not growing during this time. Indoor gardeners should fertilize their houseplants on a regular basis in spring and summer when plants are actively growing.

How can I raise the relative humidity indoors for my

Many houseplants prefer a relative humidity of 40 percent to 50 percent. Unfortunately, the humidity level in many homes during the winter months may be only 10 percent to 20 percent. Humidifiers are an excellent way to increase the relative humidity in the home. Simple cultural practices can also increase the relative humidity around houseplants. Grouping plants together is an easy way to raise the humidity level. The water evaporating from the potting soil, plus water lost by plant foliage via transpiration, increases the relative humidity in the vicinity of the houseplants. Another method is to place houseplants on trays (saucers) filled with pea gravel or pebbles. Add water to the trays, but keep the bottoms of the pots above the water level. The evaporation of water from the trays increases the relative humidity around the plants.

What are proper indoor
temperatures for houseplants in winter?

Most houseplants prefer daytime temperatures of 65 to 75 degrees Fahrenheit and night temperatures of 60 to 65F. (In winter, day and night temperatures in the lower range of the aforementioned temperatures are fine for most houseplants.) Temperatures below 55F or rapid temperature fluctuations may harm some plants. In winter, keep houseplants away from cold drafts and heat sources (such as fireplaces, furnace vents and radiators). Also, make sure houseplant foliage doesn’t touch cold windows.