REPEAT AFTER ME: “Only the healthy houseplant is decorative, and only the decorative plant is worthy of display.” Ferns with brown, withered fronds, geraniums with sick, yellowed foliage, and pitiful vines bearing only a few leaves at their very tips can’t possibly enhance the mood of a room. And here are seven rules that will keep your potted friends looking their decorative best:
1. Give them bright light or sun. The old adage “foliage plants require light; flowering plants demand sun,” is still a good rule to follow, but there are exceptions. Impatiens, wax begonias, cyclamen and primula can bloom with almost no sun at all, and certain green-growers, including ferns and vines, can benefit from direct sun in winter. But no growth is possible in darkness; plants require light to manufacture food.
2. Aim for cool temperatures. The same jasmine that blooms in a 50-degree greenhouse is sure to fail in your 70-degree living room. Thus, strive to keep temperatures on the cool side. Coolness is particularly desirable for plants that bear fragrant flowers. I removed the storm sashes from a few of my windows in order to provide my heliotrope, primroses, freesia (above) and other aromatic growers with the chilly conditions they prefer. Tropical plants, too, prefer a cool, humid room to one that is hot and dry. To keep all of my plants happy, I never raise my thermostat higher than 65 degrees, and I always lower it five or ten degrees at night.
3. Provide humidity. When the tips and/or edges of leaves turn brown, or when leaves turn yellow and drop, or when flower buds fall off before opening, a too-dry atmosphere is usually to blame. (Dry air is also an invitation to the red spider, who will weave tiny webs around leaves.) Most plants enjoy relative humidity in the 40 to 60 percent range, a definite challenge in winter. For when the furnace is running, humidity plummets. If you suffer from dry skin and a scratchy throat during the heating season, just imagine how miserable your plants are! (Air-conditioning also produces a dry environment.)
To boost humidity, set your pots on a pebble-filled tray. When plants are watered, surplus will drip into the tray, and produce humidity as it evaporates. More water, poured daily into the tray, will insure a steady source of evaporation. The pots, of course, must rest on the pebbles, above the level of water. Pebble-filled saucers are a useful alternative to trays.
4. Water only when necessary. Monday may be laundry day, but it is impossible to schedule such a routine for watering your houseplants. Daily inspection is the best policy. When a clay pot appears light in color, or when the top soil approaches dryness, go ahead and water. Make a thorough job of it, too, by completely soaking the root mass until water drips from the drainage hole. Then, unless the plant rests on a humidifying bed of pebbles, immediately empty the saucer. Few plants beyond the primrose and cyclamen will tolerate standing water at their roots.
5. Remember to feed. I give my plants a small amount of food with every watering. Those grown in windows receive a quarter-teaspoon of food, dissolved in a gallon of room-temperature water. Plants that grow beneath fluorescents in my kitchen and study receive more food, because they work such long hours each day regardless of the season or weather. I give them a half-teaspoon of formula per gallon of water.
6. Freshen the air. A daily dose of fresh, humid air will greatly increase a plant’s resistance to disease. During the mild weeks of late spring and early fall, provide ventilation by opening every window in your home. In winter, open a window in an adjoining room for a few minutes each day. This will permit the air to warm as it travels to your plants.
7. Loosen the top soil. Over time, regular top-watering causes the surface soil in a pot to become so hard and compacted that air can not pass through. This is particularly dangerous for plants grown in nonporous plastic or glazed pots. Once each month, loosen the top soil with a kitchen fork. Poke about gently, however, to avoid damaging roots that may lie near the surface.
You might want to print out this post, and tape it to your refrigerator. Then, if your petunia peters out, or your heliotrope looks haggard, you can easily review these seven essentials for health and beauty. In any event, let me know how your houseplants are doing by posting a comment below.
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