How to Care for a Closet Plant

Different varieties of closet plants (Spathiphyllum spp.) brighten shady spots in U.S. Department of Agriculture plant hardiness zones 11 through 12 with exotic white flowers and glossy green foliage. Elsewhere, they're houseplants that double as air purifiers. Also called peace lilies, their greatest drawback is toxicity. Wear gloves when you handle one, and keep leaf-nibbling pets away.

When the top 1 inch of its soil feels dry, water your closet plant until the soil is evenly moist, but not soggy. Use room-temperature water free of chlorine and fluoride. Treat an indoor plant to a weekly misting with soft or distilled water. Preserve the soil moisture around an outdoor plant with a 2-inch layer of organic mulch spreading to the farthest reaches of its leaf tips.

For large, abundant blooms, fertilize your closet plant when its soil is moist from a recent watering. Dissolve 1/8 teaspoon, or one-fourth of the label's recommended amount, of water-soluble 20-20-20 houseplant fertilizer in 1 gallon of water. Fertilize an indoor plant monthly from spring to fall, and an outdoor one twice each year, in spring and fall.

Give an indoor closet plant a spot protected from winds with daytime temperatures between 65 and 75 degrees Fahrenheit and 10 F lower at night. Its growth slows dramatically below 60 F. If it's summering outside, bring it in for the winter when the days are regularly 50 to 60 F. Protect an in-ground plant with a frost cloth at 35 to 40 F. Nothing saves it from a hard frost.

Root rot is the closet plant's most common disease. If your plant remains wilted even in wet soil, lift it from its pot and trim off any decaying roots. Repot it in a clean clay pot with fresh potting mix. In the future, water only when the top 1 inch of the mix is dry and empty its runoff saucer immediately. Always use a pot with at least one drainage hole.

White, waxy mealybugs may colonize closet plant's leaves and stems to feed on its sap. Dab the pests with cotton swabs dipped in isopropyl rubbing alcohol, or spray the plant with ready-to-use insecticidal soap until all its leaf surfaces drip. Repeat the soap treatment weekly, or at the manufacturer's recommended frequency, until the infestation is gone. Wear waterproof gloves, protective clothing and eyewear and a respiratory mask and follow the label's directions when spraying. Spray a houseplant outdoors, if possible.

Too much fertilizer or improper watering may turn your closet plant's leaf tips brown. After correcting the problem, prune the browned leaves so healthy ones can replace them. The white flower bracts deepen to green after about 10 days. They'll last another month, but pruning them encourages new ones. Disinfect your pruning tools by wiping them down with a cloth dipped in rubbing alcohol between cuts.

Closet plants benefit from repotting every one or two years. In February or March, move your plant to a container one size larger than its existing one. For the best results, use a potting medium with equal parts of sand, loam and peat moss.