Winter Survival Guide for Houseplants
Pay attention to the details
James Wisniewski maintains more than 300 houseplants.
Photos by Luke Copping
Many plant lovers still grow Great Grandma’s staples: foliage plants such as snake plants, spider plants, and philodendrons. They survived the dim light of Victorian houses and tolerate the smallest of windows in dorm rooms or apartments. Now, new gardeners and home decorators are embracing succulents, bromeliads, and tropical foliage plants.
The styles change. What doesn’t change is that plants need specific conditions and care to survive and look attractive. Different plant groups have different needs. The top reasons that indoor plants fail are poor watering (too much or too little) and insufficient light.
• Water plants when they need it, not according to a schedule. Within the same species, water needs vary depending on the room temperature, light, humidity, whether the pots are clay or plastic, and whether the plants are rootbound or have ample soil.
• Let most plants get dry between watering. Only a few require constant moisture—Anthurium (Peace Lily) is the best example but most thrive on the drier side.
• To feel for dryness, stick your finger an inch into the soil. Or lift the pots: a light pot is dried out.
• Never let plants stand in water in their saucers; always empty the saucer after a thorough watering. (Exception: a few plants, such as African violets, like bottom-watering.)
• Extremely hard water (alkaline, with a high pH) can be a problem for some plants. If your water is hard, let it stand overnight before use, or boil and then cool it before using. A water filter is helpful, but do not use water from a water-softening system.
• Very cold or hot water can shock plants; use warm or room-temperature water.
Johanna Dominguez has made several adaptations to her historic Allentown home to make it hospitable to plants.
Light plants better
Clues to insufficient lighting include legginess (stems stretched out) and pale leaves. The brightest indoor light from windows is usually the equivalent of outdoor shade, so “full sun” plants are unlikely to get the light they need indoors unless you have a conservatory, sun room, or use supplemental lighting.
Light from windows
Southern light is brightest; use those spots for tropical plants or for plants with tags that read “Requires bright light.” Eastern light is similar to all-day dappled shade outdoors and suits many plants very well. Northern light is dim, accepted only by African violets and a few others. Western light—hot in the afternoon—adds lots of sunshine but it’s tricky; some plants burn in the heat that is accentuated by window glass, seen as browned or crinkled patches on the leaves. When in doubt, rotate some plants throughout the season, so that most of them get occasional good doses of sunlight.
Lighting supplies and products have improved over the years, from older-style fluorescents to intense LED lights. With a little research or a trip to the hydroponics store (several choices in our region), you may find products that will work for your plants and you. (See Spree, February 2019.) Lighting the room helps all plants greatly, and significantly improves many people’s moods and spirits, especially those afflicted by Seasonal Affective Disorder (SAD).
However you can, get more water vapor into the air. Additional watering is not the same thing; it does not help. Lower the room temperatures, especially at night. Most plants require at least forty percent humidity. Tropical plants require at least sixty percent, which is much higher than the typical home. Plant symptoms are shriveling leaf tips and browning—palms and ferns the first to go. Use these techniques to increase the humidity around your plants:
• Cluster your plants: together they form a more humid environment. You can increase this effect by placing a clear plastic dome over them. Punch holes in it to let excess moisture escape. (This technique is especially good when you go on a short vacation.) A terrarium provides similar conditions.
• Suspend them over water: place your pots on pebbles or rocks over a large tray. Never let the plants sit in the water.
• Invite them into the shower: bathrooms can be great houseplant rooms, with lots of humidity, if the lighting is right. If your plants can’t live there, at least move a few into the shower from time to time.
• Add humidifiers: whether free-standing or built into the home heating system, humidifiers make most living things much more comfortable.
• Misting requires persistent repetition to make any difference at all. It does benefit plants by washing dust off the leaves but, for humidifying, misting is not enough.
Let them rest
After a lively growing and flowering season, most plants benefit from a rest period. Letting them rest does not mean that you stop all watering, but it does mean that you gradually decrease watering and stop fertilizing when the plant isn’t growing. (An exception: if you want your Streptocarpus, goldfish plant, or geranium to flower in January, keep fertilizing. Give it a rest later.) If you have ceased watering so much that the soil separates from the sides of your pot, you’ve gone too far. Add soil mix and re-soak the plant.
Managing your indoor plants is not an overwhelming chore or challenge. Begin with these few principles, and then pay attention as they declare what is working for them and what is not.