If you’re occasionally at a loss about how to keep your houseplants as beautiful as they were the day you bought them, you’re not alone. We’ve compiled some of the most common indoor-plant questions and answered them for you.
Q. How often should I water my houseplants?
A. Plants tend to thrive when they’re watered as needed, rather than on a strict schedule. To determine how often and how much to water your plants, keep in mind their native habitats, as most plants have genetically programmed water requirements.
For example, foliage plants from tropical areas obviously have a much greater water requirement than desert cacti and succulents. That said, natural conditions are very different from those in your home, and the local environment is the primary factor in your plants’ immediate water needs. Artificial heat can cause rapid drying, which means plants situated near a heat source need to be watered much more frequently than those in a more temperate location. Because plants in low-light conditions grow more slowly than those in full sun, they require less water. And almost all plants prefer to spend winter on the dry side while they take a rest, but there are no absolutes. Observe your plants carefully to see how their environment affects them. Check the soil frequently, touching it and even gently digging down an inch or so to check how dry it is before automatically watering the plant every few days or weeks. Pick up the pot. Does it feel heavy and saturated with moisture? Is it light and dried out? Far more plants die from overwatering than underwatering. When in doubt, wait another day or two before watering, and then reassess.
Q. Which plants will flower indoors?
A. African violets are among the most reliable and beloved flowering houseplants. They bloom profusely year-round when exposed to bright, diffuse light, spending just a few weeks recuperating between periods of blossoming. African violets are members of the Gesneriad family.
Many of the violet’s relatives share its propensity to blossom repeatedly and are just as easy to grow, among them Cape primrose (Streptocarpus), lipstick plant (Aeschynanthus), and goldfish plant (Nematanthus). Peace lily (Spathiphyllum) is another beautiful workhorse, displaying long-lasting white flowers most of the year. The key to abundant blooms is keeping the plant happy and stress free. If it is struggling to stay alive, it won’t spend precious energy on flowering. To maintain a dramatic display of flowers, treat yourself to the seasonal flowering plants you see in nurseries, such as cyclamen, orchids, primroses, cineraria, azaleas, and hydrangeas. If kept in cool, bright spots, their displays should last up to several weeks.
Q. Can I grow herbs indoors?
A. We like to say that “no plant is native to your house.” This means that a plant’s native needs are not met in common indoor conditions. This is especially true of herbs. Many culinary herbs—basil, rosemary, thyme, and oregano—are native to the Mediterranean region, where they enjoy bright sun, cool breezes, and warm soil. Most homes simply don’t let in enough light to grow these plants inside, but it’s worth trying if you have large, unobstructed windows facing south or east. You probably won’t grow enough basil to make pesto, but chances are you’ll be able to harvest a sprig or two, which will make a welcome addition to almost any dish, especially in the middle of winter.
Q. What is the best spot for growing houseplants?
A. As with watering, it’s hard to generalize. Your home’s sun exposure and heating system drastically affect its light and temperature, two variables crucial to creating the ideal climate for a plant’s healthy development.
Windowsills are common plant perches, but the light is often better a few feet from the window, so don’t neglect nearby coffee and side tables. Direct indoor light may be too bright for some plants. If a plant is drying out too quickly, try a different location.
Areas that are not in direct sun but are still bright throughout the day are ideal for many popular houseplants, including begonias, orchids, and most tropical foliage plants. If a plant doesn’t do well in one spot, try different places, leaving the plant in a given location for at least a month at a time, until you find a place that suits it. Temperature and humidity are also important factors. In winter, most plants thrive in a climate that’s cooler and more humid than most homes. To compensate, mist tropical plants frequently. And keep them in a location that has a low temperature at night (ideally 55° to 60°F). Your plants will appreciate it.
Q. What types of plants can I grow in rooms that receive only average or low light?
A. All plants need light in order to photosynthesize, but some are better than others at dealing with minimal light. Aspidistra, a common landscape plant in the South, is known as the cast-iron or barroom plant— accurate and descriptive terms for this undemanding favorite.
Sansevieria, commonly referred to as snake plant, also tolerates low or artificial light, as does Aglaonema, or Chinese evergreen. Spathiphyllum, or peace lily, is another option, but it may not flower in very dark conditions.
Don’t purchase these plants with high expectations; they tend not to grow as quickly or as large as their sun-basking counterparts.
Q. There are small insects flying around my plants. What are they? Are they doing any harm?
A. What you have are probably fungus gnats. These small insects are common and harmless, but they can be a bit of a nuisance and may signal an overwatered plant. Moist soil is the ideal place for their tiny, wormlike larvae to develop, so fungus gnats tend to conglomerate around plants when they lay their eggs. The larvae are harmless, too; they eat bits of fungus that live in the soil, not plant roots. To get rid of fungus gnats, simply cut back on watering, since the larvae are unable to survive in dry soil. You can go a step further by covering the soil surface 1/2– to 1–inch deep with a mulch of small pebbles or decorative glass.