How to grow a peace lily

The name 'peace lily' relates to its white flowers, which are thought to look like white flags (a symbol of peace). The peace lily isn't actually a lily but an arum, and belongs to the same family as Zantedeschia and lords-and-ladies (Arum maculatum), as well as less obvious plants such as the Swiss cheese plant (Monstera deliciosa) and dumb cane (Dieffenbachia). Peace lilies are easy to grow, and help to clean and purify the air.

Although the peace lily will grow in poor light, it flowers better in bright, indirect light and will struggle to produce blooms if it is in deep shade. Peace lilies usually begin flowering in early spring, with each flower lasting up to four weeks. If your peace lily hasn't flowered, this may be because it hasn't reached maturity.

Tips for growing peace lily

• Grow peace lily in a bright spot out of direct sunlight.
• Water regularly, keeping the compost moist but not wet.
• In spring and summer, feed fortnightly with a liquid house-plant food.
• Deadhead spent blooms, and dust or wipe the leaves regularly to ensure they photosynthesise well. In dry rooms, you may need to mist around the leaves occasionally to raise humidity levels.
• Bear in mind that, if ingested, peace lily leaves can cause swelling of the tongue or vomiting.

Where to position a peace lily

Peace lilies thrive in spots with bright, indirect sunlight. It does not like cold draughts, so choose a location away from doors and fireplaces. Peace lilies are used to a tropical environment, so a humid room, such as a bathroom or kitchen, is ideal.

How to pot a peace lily

Peace lilies are best potted up in spring. First, check the plant's roots - if they are densely packed, then it needs to be transferred to a bigger pot. Choose a container that is a third larger than the plant's rootball - any larger and the plant may suffer from root rock. Fill it to two-thirds of the way up with peat-free multi-purpose or house-plant compost mixed with perlite to improve drainage. Place the peace lily in the centre, then fill around the rootball with more compost. Gently firm in. Water well and allow excess water to drain.

Caring for a peace lily

Water your peace lily regularly, so the compost never completely dries out but also making sure that it is never waterlogged. As a general rule, wait until the top few centimetres of compost have dried out before watering again. If you don't water peace lilies often enough you'll soon be able to tell as they wilt when dehydrated. Simply water them again and adopt a regular watering regime.

In spring and summer, feed your peace lily fortnightly with a liquid plant food, following the manufacturer's instructions.

Repot your peace lily into a slightly larger pot, with fresh compost, every few years. They do well when their roots are a bit restricted, but recurrent wilting, despite regular watering, is a sign that the plant has outgrown its pot.

Peace lily pests and problem-solving

• Small flies around the compost will likely be fungus gnats. Fungus gnats thrive in moist compost, so try to water less frequently to break their lifecycle. You could also leave home-made traps in shallow dishes to lure and kill them – they're attracted to sweet-smelling diluted cordial, wine and beer. Alternatively, apply the organic pesticide Bacillus thuringiensis (Bt) to the soil to kill the larvae.
• Yellow leaves – the occasional yellow leaf is natural, so snip it off to make room for fresh leaf growth. Overwatering your peace lily may also lead to yellowing leaves, so let the soil dry out a bit to see if that makes any difference.
• Brown edges on the leaves indicate that your peace lily is getting too much direct sunlight. Simply move the plant out of direct sun to somewhere more shaded (ideally to a spot with bright, indirect sun).