A Beginner's Guide to Keeping Houseplants Alive

Houseplants can brighten a room and are rewarding to care for, but many first-time owners lose a few. Most problems come from the same causes: too much water and too little light. With a few basics, you can keep plants healthy.

Key takeaways

• Match the plant to the light available in your home.
• Overwatering is a more common killer than underwatering.
• Check the soil before watering, not the calendar.
• Use pots with drainage holes and a suitable potting mix.
• Start with forgiving plants while you learn.

Start with easy plants

Some species tolerate beginner mistakes. Good starters include pothos, snake plant, ZZ plant, spider plant and peace lily. Succulents and cacti suit sunny, dry spots. Check the plant label or a reliable guide for each plant's light and water needs, and keep in mind that some plants are toxic to cats, dogs or children, so check before buying if you have pets.

Understand light

Light is food for plants. Notice how sunlight moves through your home. A south- or west-facing window in the Northern Hemisphere usually gives bright light, an east window gentler morning sun and a north window the least light. Plants labelled low light still need some light. If a plant stretches toward the window with long, thin stems, it may need more. If leaves look scorched or bleached, it may be getting too much direct sun.

Watering wisely

Most houseplants prefer to dry out slightly between waterings. Push a finger about two to three centimetres into the soil: if it feels dry, water thoroughly until water runs out of the drainage holes, then empty the saucer. If it is still damp, wait. Succulents need to dry out more, while ferns prefer moist soil. Watering needs change with the season, since plants use less water in cooler, darker months.

Pots and soil

Pots should have drainage holes so excess water can escape. Decorative pots without holes can be used as outer covers around a plastic nursery pot. Use a potting mix labelled for indoor plants, as garden soil can be too heavy and may carry pests. Cacti and succulents do better in gritty, fast-draining mixes.

Feeding and repotting

Plants need little fertiliser. During the growing season, spring and summer, a diluted balanced houseplant fertiliser every month or so is enough for many plants, following the label's directions. Repot when roots grow out of the drainage holes or the plant is crowded, usually every year or two, into a pot only slightly bigger.

Troubleshooting

• Yellow lower leaves: often overwatering, though old leaves also naturally yellow.
• Brown, crispy tips: low humidity, underwatering or fertiliser build-up.
• Drooping: can mean thirst or too much water, so check the soil first.
• Small flying insects: fungus gnats often come from constantly damp soil.
• Sticky leaves or cottony spots: may signal scale or mealybugs. Isolate the plant and wipe pests off, or follow product guidance.

Habits that help

Dust leaves gently, rotate plants for even growth, group plants away from cold draughts and heaters, and observe weekly. Learning your plants' signals takes time, and a few losses are a normal part of learning.

Light levels with examples

Plant labels talk about low, medium and bright light, which can be confusing. Bright light means a spot within a metre or so of a sunny south- or west-facing window, with some direct sun. Medium light is a few metres from a bright window or near an east-facing window. Low light is a corner or a north-facing room, where you can still read comfortably but no sun reaches. Snake plants, ZZ plants and pothos tolerate low light, though they grow more slowly. Many ferns and peace lilies like medium light. Succulents, cacti and many herbs need bright light with direct sun. A simple test is to hold your hand above the plant and see how sharp the shadow is, because a crisp shadow suggests bright light.

Watering techniques

Besides watering from above, you can try bottom watering. Stand the pot in a bowl of water for about twenty minutes and let the soil soak it up through the drainage holes, then let it drain. This encourages deep roots and avoids splashing leaves. Self-watering pots and wicking systems can suit people who travel. A moisture meter or a wooden skewer pushed into the soil helps you judge when to water. Most houseplants prefer water at room temperature, and tap water is usually fine, although letting it stand for a day lets chlorine dissipate for sensitive plants.

Propagation

Plants are easy to multiply. Pothos, philodendron and tradescantia root readily from stem cuttings placed in water or damp compost, with a node, the point where a leaf joins the stem, below the surface. Succulents can be grown from leaves, and spider plants produce baby plantlets that can be potted. Large clumps, such as peace lilies and snake plants, can be divided at repotting time. Propagating gives you free plants and a back-up if the parent suffers.

Pests in detail

Common houseplant pests include spider mites, tiny sap-sucking creatures that leave fine webbing and speckled leaves, mealybugs that look like white cottony fluff, scale insects that form brown bumps, and fungus gnats that hover around damp soil. At the first sign, isolate the plant so pests do not spread. Wipe leaves with a damp cloth, and treat with insecticidal soap or an appropriate product according to the label. Letting the soil dry out more between waterings helps control fungus gnats. Check new plants carefully before putting them with others.

Pets and the air-quality myth

Some popular plants are toxic to pets. Lilies are especially dangerous to cats, and others, such as pothos, peace lily and philodendron, can irritate the mouth and stomach. Check lists from veterinary or animal welfare organisations before buying, and place plants out of reach. You may have heard that houseplants purify indoor air. A 1989 NASA study found that plants removed chemicals in small sealed chambers, but later reviews suggest that you would need huge numbers of plants to make a real difference in a normal home, where ventilation is far more effective. Plants are worth having for their beauty and the pleasure of caring for them.

Frequently asked questions

How often should I water?

It depends on the plant, pot, light and season. Check the soil instead of following a fixed schedule.

Do plants need misting?

Misting has a short-lived effect. Grouping plants or using a humidifier works better for humidity-loving species.

Can I use tap water?

Usually yes. Some sensitive plants prefer rainwater or water left to stand.

How often should I repot a houseplant?

Most plants need repotting every one to two years, or when roots circle the pot or poke out of the drainage holes. Choose a pot only one size larger, use fresh potting mix and repot in spring when plants are growing.

Do houseplants really clean the air?

Not enough to matter in a typical home. Studies in sealed laboratory chambers showed some effect, but opening a window or using ventilation is far more effective. Plants may help mood and wellbeing, which is a good reason to keep them.

Can I keep plants in the bathroom?

Yes, if there is enough light. Many ferns, peace lilies and orchids like the humidity. A windowless bathroom is too dark for most plants unless you add a grow light.

Sources and further reading

• Houseplant (Wikipedia)
• Royal Horticultural Society: House plants