Swiss cheese plant

Light and exposure

The Monstera wants bright but filtered light. A spot a metre from an east or west-facing window suits it perfectly. Avoid the direct midday sun in summer, which scorches the leaves and leaves dry brown patches. In too deep a shade, the plant survives but its leaves stay small and solid, without the cutouts that make all its appeal.

At our latitudes, winter light is weak and short from November to February. Move the pot closer to a south-facing window then and turn it a quarter turn each week, otherwise the plant stretches towards the glass and leans to one side.

Watering

Let the first three to four centimetres of substrate dry out before watering again. In practice, that amounts to one watering a week in spring and summer, then one every ten to fifteen days in winter, when growth slows. Push a finger into the soil rather than following a fixed calendar.

Always empty the saucer after watering. Roots soaking in stagnant water rot fast, and that is by far the leading cause of death of the Monstera in a flat. Tap water is fine in most regions, but if your leaves get covered in white deposits, yours is hard: let it stand overnight, or collect rainwater.

Soil and repotting

The Monstera hates compact substrates that hold water. Mix a potting soil for green plants with a good handful of orchid bark and some perlite to keep it all aerated. A pot with drainage holes is essential.

Repot in spring every two years, or as soon as the roots come out through the drainage holes. Choose a pot barely larger than the previous one, because too large a volume of soil stays moist too long and rots the roots.

Temperature and humidity

The ideal range is between 18 and 27 degrees. Below 12 degrees, growth stops; below 10 degrees, the leaf margins blacken. Keep the Monstera away from scorching radiators as well as from cold draughts near doors and single-glazed windows.

The real problem is not the cold, it is the air dried out by heating throughout the heating season. Leaf tips that brown and dry out betray air that is too dry. Set the pot on a bed of moist clay balls, or run a humidifier in the room; misting, for its part, only lifts the humidity for a few minutes.

Pruning and upkeep

Give the Monstera a moss pole as soon as it grows: it is a climbing plant, and a support helps it produce larger and better-cut leaves. Guide the aerial roots towards the pole or into the pot.

In spring, cut the stems that have grown too long just above a node. Do not throw away these pieces, they are easy to propagate. Regularly wipe the dust off the leaves with a damp cloth so the plant can breathe and catch the light better.

Pests and diseases

Mealybugs, small cottony clusters in the leaf axils, and red spider mites, which weave fine webs under the foliage, appear mainly when the air is dry in winter. Remove them with a cotton pad soaked in diluted methylated spirit and increase the humidity of the room.

Leaves yellowing en masse almost always signal excess water and the start of root rot. Take out the rootball, cut off the soft brown roots, and repot in fresh, dry substrate.

Propagation

The Monstera is very easy to propagate in spring or summer. Spot a node, that little bump from which a leaf and often an aerial root emerge, and cut the stem just below it. Place the cutting in a glass of clear water, change the water every week, and wait for roots of a few centimetres to form before repotting in soil.

A cutting without a node will never make roots, even if it stays green for several weeks. It is the node that matters, not the leaf.

Toxicity

The whole plant contains calcium oxalate crystals. Chewed, a leaf causes a strong irritation of the mouth and throat. Keep the Monstera out of reach of cats, dogs and young children.

Month-by-month care calendar

Green Hub tips

• The leaves only fenestrate with age and good light. A young plant with solid leaves is nothing abnormal, you just have to give it time.
• Never cut off the dangling aerial roots: guide them towards the pole or plunge them into the pot, they feed the plant.
• A Monstera that leans is seeking the light. Turn the pot a quarter turn each week so it grows straight.
• To take cuttings with certainty, always keep a node below the cut. No node, no roots.