Looking after orchids

How to water

Overwatering is the most common way to kill orchids. To avoid giving your plant too much water, always lift the pot first to check if it feels heavy - water only when it feels light. If your moth orchid is in a transparent pot, look at the roots. Don’t water if these are green - wait until they look silvery. Feed with orchid fertiliser from spring until autumn.

Get the light right

Stand orchids where they’ll receive bright but indirect light. An east- or west-facing windowsill is perfect. Too much light can scorch the leaves, causing damage that will last for many years. If your orchid gets scorched, don’t detach the damaged leaves unless the plant has several additional healthy leaves.

Boost humidity

Most indoor orchids come from humid, tropical regions, so these plants appreciate a humid atmosphere. In most centrally heated homes the air is dry, so mist the foliage every two to three days using tepid water, but avoid spraying the flowers, as the petals can get marked by water. Alternatively, stand the pot on a tray of damp gravel.

Encourage flowering

With moth orchids, once all the flowers have fallen, cut off the stem just above a visible joint (node). This may stimulate the production of another flower stem. If no shoot appears and original stem turns straw-coloured, then remove it at the base. Most other orchids won't flower twice on the same stem, so cut off spent stems immediately.

Potting on

Unlike most other pot plants, orchids don’t need regular re-potting and often thrive when root-bound. However, after two or three years it’s worth taking them out of their pots and removing as much of the compost as possible. Replant in the same pot with fresh orchid compost or choose a slightly larger pot if the plant won’t fit.

Treat pests

The most common orchid pests are scale insects and mealybugs. Signs of infestation include stickiness on the leaves or nearby surfaces, or black sooty mould. Scale insects can be found on the leaf surfaces (above and below) and flower stalks, while mealybugs prefer new leaves. Remove pests by hand or spray with a systemic insecticide.

Check the label

Always keep the plant label, as different types of orchid need slightly different care. For example, showy Vanda orchids - which are often grown in glass vases without compost - require a specific watering regime. Fill the vase with water daily in summer, then empty it after half an hour. Vandas also need direct sun, which would scorch a moth orchid.

Plant feature by Dr Ross Bayton.