Prayer plant

The prayer plant grows across the forest floor of Brazil, spreading sideways in deep shade under a canopy that keeps the air damp and the light low. The leaves are patterned like nothing else in a house, with dark blotches either side of a pale midrib and, in the best known form, red veins running out to the edge. It is a close relative of the calathea and wants the same three things: shade, humidity and water without chlorine in it. It is a little more forgiving than its cousin, which makes it the better place to start.

Light

Medium indirect light. It grew under a canopy and it shows: direct sun through glass fades the red veins and bleaches the dark patches to a flat green within a fortnight, and that damage does not reverse on leaves that already exist. A north window in the northern hemisphere or a south one in the southern is right, or a few metres back from a brighter window.

If you are choosing between too bright and too dark, choose too dark. This plant keeps its markings better in a dim room than a sunny one.

Water and humidity

Keep the compost lightly moist, watering about every five days in summer and every nine in winter. Let the surface dry slightly between waterings, and never let the pot dry all the way through. Water at the base, let it drain, and empty the saucer.

Use rainwater or filtered water if you can. Like the calathea it is sensitive to chlorine and dissolved minerals, which accumulate at the leaf edges and burn them brown, and the difference shows on new growth within a season.

Humidity is the other requirement. A bathroom or kitchen suits it well, and elsewhere a tray of wet pebbles and a group of neighbouring plants both help. Keep it well away from radiators and air conditioning, which dry the air around a plant faster than the room as a whole.

The nightly movement

At dusk the leaves rise and fold together like hands, and at dawn they lower again. A small hinge of swollen tissue at the base of each leaf stalk, called a pulvinus, changes shape as the light goes, and the whole plant repeats the movement every day. It is worth watching for its own sake, and it is a useful health check: a prayer plant that has stopped folding is usually too cold, too dry at the root or standing in water.

Feeding and repotting

Feed at a quarter to a half strength, monthly through spring and summer, and nothing in winter. Overfeeding shows as brown leaf edges and is easily mistaken for a watering fault.

Repot in spring into a shallow pot rather than a deep one, because the roots run sideways and a deep pot simply holds wet compost below them. One size up is enough. Use a compost with coir and a little perlite so it holds moisture without going heavy.

Pruning and propagation

Cut tired or damaged leaves out at the base of their stalks. A plant that has gone leggy and bare in the middle can be cut back hard in spring and will fill out again from the base within a couple of months.

Cuttings root readily. Take a piece of stem with two or three leaves, cutting just below a node, and stand it in water; roots appear in two to three weeks and it can be potted once they are about three centimetres long. Division at repotting works too and gives a fuller plant more quickly.

Ailments

Brown edges are dry air or tap water. Curling leaves are thirst and open again within a day of watering. Faded markings mean too much light. Yellow lower leaves with a wet pot mean the roots are drowning. Spider mites take hold when the air is dry, so the cure for them is the cure for most of the rest. The ledger below has the detail.