Houseplant care basics

Look at the spot before the plant

The first step to keeping plants alive is not buying one you like but knowing what light your home gets. Even at the same window, the amount of light varies greatly with the direction, the buildings opposite and your curtains. Sort your spots into those with direct sun for part of the day, bright places without direct sun, and darker places far from a window. Then choose plants that suit each spot, and failures drop sharply. When buying, ask the seller how much light the plant likes and how often to water it, and keep the label so you can look things up later.

Water by the soil, not the calendar

Indoor plants die from overwatering more often than from thirst. Roots need air too, and soil that is always wet damages and rots them. So the rule is to water by the state of the soil rather than on a fixed schedule like once a week. Push a finger into the soil to feel how deep it has dried, and if it is dry, water thoroughly until water runs out of the drainage hole. Empty the saucer straight away. Plants differ in how dry they like it: thick-leaved succulent types should dry out completely, while thin-leaved plants want water a little sooner.

• Check soil dryness with a finger
• When you water, water until it drains out the bottom
• Empty any water left in the saucer
• Lifting the pot to judge its weight also works

Pots and soil

A pot with no drainage hole collects water at the bottom and leads to overwatering. If you want to use a decorative pot without a hole, plant in a pot with a hole, set it inside, and tip out any water that collects in the outer pot after watering. A pot that is far too big for the plant stays wet for a long time and damages the roots, so a pot slightly larger than the root ball is right. Use free-draining indoor potting mix rather than garden soil. When roots poke out of the drainage hole, or water runs off the surface instead of soaking in, it is time to repot.

Signals from the leaves

Plants tell you about problems through their leaves first. But one symptom can have several causes, so look at your watering interval and the plant's position together rather than jumping to a conclusion. The list below shows common tendencies only, so treat it as a guide.

• Lower leaves yellowing and soil always wet: suspect overwatering
• Leaves drooping and soil bone dry: too little water
• Stems growing long and thin and leaning one way: not enough light
• Brown scorched patches on leaves: strong direct sun or cold draughts
• Tiny spots or stickiness under leaves: check for pests

Adjust with the seasons

Most indoor plants grow in the warm months and slow down in the cold. While they are not growing they drink less, so space out watering in winter. Window sills get colder at night than you might think and can chill leaves, so move plants back a little, and keep them out of the direct blast of heaters and air conditioners. In humid spells such as the rainy season, soil dries slowly, so water less and pay attention to ventilation. Feed only in the growing season, lightly and according to the product instructions, and it is safer not to feed plants that are struggling or during winter.

Pests and hygiene

Indoor pots can attract small flies hovering over the soil or pests clinging to the undersides of leaves. Constantly damp soil encourages the flies, so adjusting your watering interval is the first fix. Keep new plants apart from the others for a few days and check under their leaves to stop pests spreading. Dust on leaves blocks light, so wipe them occasionally with a damp cloth. Lots of plants can raise indoor humidity, so if your home is already damp, keep up with ventilation.

Common misconceptions and cautions

It is best not to expect a few plants to make your indoor air noticeably cleaner. Plants lift your mood and bring a space to life, but they do not replace ventilation. Also, some plants often recommended as easy to grow are harmful if cats, dogs or young children chew or swallow the leaves. Lilies in particular are known to be dangerous to cats. If you have pets or children, check whether a plant is safe before bringing it home and keep it out of reach. If a pet shows signs such as vomiting or lethargy after eating a plant, contact a vet without delay.