To many people, a home is not a home without potted plants. But there’s more to it than aesthetics. Keeping potted plants inside the house is a breath of fresh air….literally. Studies done by NASA scientists researching ways to create healthy environments on the space station have shown that plants purify indoor air through photosynthesis, which is when they absorb carbon dioxide and release oxygen. They also remove air-borne toxins – up to 87 percent of volatile organic compounds (VOCs) every 24 hours, according to NASA research. Plants pull contaminants into soil, where microorganisms convert VOCs into food for the plant. And plants release roughly 97 percent of the water they take in. Place several together and you can increase the humidity of a room – especially helpful during dry winter months. Studies at the Agricultural University of Norway tell us that houseplants help prevent dry skin, colds, sore throats and dry coughs.
“Improper watering is the most common culprit when it comes to killing houseplants,” says Scott Cronin, our retail greenhouse manager. Soil that is too wet or too dry will lead to poor growth – or death of the plant.
Plants can be watered from either the top or the bottom of the pot. If you water from the top, keep as much water off the foliage as possible. Water until it runs out through the pot’s drainage. Toss any water that remains beneath the pot one hour after watering.
To water from the bottom, put the pot in a pan or saucer filled with water. When the top of the soil is moist, remove the pot and allow it to drain. “Never allow plants to wilt, and never let a potted plant sit in water for any length of time,” says Scott. “Wet feet will cause leaves to yellow or drop, flowers to collapse, and roots to rot.”
Not enough – or too much – light ranks right up there with improper watering as a frequent cause for a plant’s demise.
Plants are generally divided by light needs: low, moderate and bright. Only a few plants can tolerate dim light. Most foliage plants do well with light at a north window, daylight with no direct sun, or sunlight diffused through a lightweight curtain. Plants that require full sunlight should be put in a south window.“If you’re not sure how much light a plant needs, just ask us,” says Scott. “We want you to choose a plant that will grow in your environment.”
A good monthly feeding is usually enough for most houseplants. Water-soluble fertilizers formulated for houseplants – like Miracle Grow – are applied when you water. Slow-release fertilizers – like Osmocote or feed “stakes”- require less frequent application than liquid forms. Whichever you choose, follow directions carefully and don’t exceed amounts suggested by the manufacturer’s directions.
Plants just purchased should not need repotting. And a plant must make adjustments to its new environment; repotting immediately can cause unnecessary strain. A time for repotting is when the plant becomes pot-bound. A rule of thumb is to go just one pot size up. Use a high quality potting mixture formulated for house plants. Garden soil shouldn’t be used; it’s too heavy.
When repotting, handle the plant gently, and be careful not to damage the roots. Firm the fresh potting mixture gently around the root ball and water well.
Insects and Diseases:
The three most common houseplant pests are spider mites, scales and mealy bugs. If detected early, these problems can usually be fixed before serious damage is done. “If you’re unsure of what’s attacking your plant, bring us a cutting that shows the symptoms,” advises Scott. “We’ll help to diagnose the problem and offer advice on what you can do to clear it up.”
During the summer, many houseplants can grow outside. But don’t rush to put them out too early in the spring; late May is usually soon enough. At first set the plants in a sheltered spot, out of direct sun. After a week or so, they may be moved to a more exposed spot for the rest of the summer. Potted plants dry rapidly outdoors; during the hottest periods you should check them daily. Fertilize monthly, and check occasionally for insects or diseases that may attack the plants outdoors. Move plants indoors by mid-September before cool weather returns.