Winter weather adversely affectsgrowing conditions for houseplants in Iowa. Proper care during thewinter months can help insure the health of houseplants.
Most houseplants grow well with daytime temperatures of 65 to75 F and night temperatures of 60 to 65 F. Temperatures below 50 For rapid temperature fluctuations may damage some plants. Keephouseplants away from cold drafts, radiators, and hot air vents.Also make sure houseplant foliage doesn't touch cold windows.
Many houseplants prefer a humidity level of 40 to 50%.Unfortunately, the relative humidity found in many homes during thewinter months may be only 10 to 20% -- a level too low for manyhouseplants. Humidifiers are an excellent way to increase therelative humidity in a single room or throughout the entire home.Simple cultural procedures can also increase the relative humidityaround houseplants. Group plants together. The water evaporatingfrom the potting soil, plus water lost through the plant foliage(transpiration), will increase the relative humidity in theimmediate vicinity of the houseplants. Another method is to placethe houseplants on trays (saucers) filled with pebbles or graveland water. The bottoms of the pots should be above the waterlevel.
Misting houseplants is not an effective method to raiserelative humidity. Misting would have to be done several timesdaily to appreciably raise the humidity level and is simply notpractical.
In general, houseplants require less frequent watering duringthe winter months than in spring and summer. Actively growingplants need more water than those at rest during the winter months.
Plant species also affects watering frequency. Ferns preferan evenly moist soil and should be watered relatively frequently.Cacti and succulents, on the other hand, should not be watereduntil the potting soil is completely dry. The majority ofhouseplants fall between these two groups. Most houseplants shouldbe watered when the soil is barely moist or almost dry to thetouch.
When watering houseplants, water them thoroughly. Watershould freely drain out of the bottoms of the pots. If the excesswater drains into a saucer, discard the water and replace thesaucer beneath the pot.
Houseplants need to be fertilized periodically when activelygrowing in the spring and summer. Fertilization is generally notnecessary during the winter months because most plants are growingvery little or resting. Indoor gardeners can begin to fertilizehouseplants in March or April as growing conditions improve and theplants resume growth. Fertilizers are available in numerous forms:liquids, water soluble powders, tablets, spikes, etc. Regardlessof the fertilizer type, carefully read and follow label directions.
Dust and grease often accumulate on the leaves of houseplants.The dust and grease not only makes them unattractive, it may slowplant growth. Cleaning houseplants improves their appearance,stimulates growth, and may help control insects and mites.
Large, firm-leafed plants may be cleaned with a soft sponge orcloth. Wash the foliage using a very mild solution of dishwashingsoap and tepid water. Another method is to place the plants in theshower and give them a good "bath". Be sure to adjust the watertemperature before placing the plants under the shower head.
This article originally appeared in the December 8, 1993 issue, p. 167.