Orchid care: how to keep a moth orchid flowering

By Sophie Sparkes · October 2026 · 6 min read

The orchid you find in supermarkets and garden centres is almost always a moth orchid, Phalaenopsis. It has a reputation for being fussy, but it is really one of the easiest flowering houseplants there is, as long as you stop treating it like a normal pot plant. It grows on trees in the wild, not in soil, and nearly every problem comes from forgetting that.

Short answer: keep a moth orchid in bright, indirect light at normal room temperature, out of draughts and direct midday sun. Water about once a week in summer and every 10-14 days in winter by soaking the pot for 10-15 minutes, then let it drain completely. Never leave it standing in water. When the flowers drop, cut the stem just above a node, or at the base if it has gone brown, and give it a few cooler nights in autumn to encourage new flowers.

Where to put an orchid

Moth orchids want bright light without hot sun. An east-facing windowsill is ideal; a south or west window works if a sheer curtain or a metre or so of distance softens the afternoon sun. Leaves tell you how it is going: a healthy plant has firm, mid-green leaves. Dark green leaves mean it needs more light. Yellowish leaves or pale scorched patches mean too much.

They are happy at ordinary room temperatures, roughly 18-27°C by day and not much below 16°C at night. Keep them away from radiators, which dry the air and the roots, and from cold glass and draughty doors in winter.

How to water an orchid

Orchids grow in chunky bark, not compost, so they need watering differently.

1. Check first. Look at the roots through the clear pot. Silvery or grey roots are dry and ready for water. Green roots are still wet, so wait.
2. Soak, don't sprinkle. Lift the inner plastic pot out of any decorative pot and stand it in a bowl of room-temperature water for 10-15 minutes so the bark can absorb it.
3. Drain completely. Let every drop run out before putting it back. Water collecting in the bottom of a decorative pot is the most common way orchids die.
4. Keep the crown dry. Avoid getting water into the centre where the leaves meet, and dab it out if you do, since water sitting there can rot the plant.

In practice this is about once a week in a warm summer room and every 10-14 days in winter. Ice cubes are popular because they are hard to overdo, but they water unevenly and soaking is more reliable.

Roots growing out of the pot

Those fat roots climbing out of the pot are aerial roots, and they are completely normal. In the wild they cling to bark and catch rain. Leave them alone; cutting healthy roots only weakens the plant. The clear pot it came in is deliberate, since the roots photosynthesise and it lets you check them.

Feeding

Use an orchid feed at the strength on the label (or weaker) every two to three weeks while the plant is growing new leaves or roots, and roughly monthly in winter. Orchids are light feeders, and too much fertiliser burns the roots.

What to do when the flowers drop

A moth orchid's flowers usually last two to three months. When the last one falls, look at the flower stem:

• If the stem is still green, you can cut it about 2cm above the second or third node (the small bumps along the stem) below where the lowest flower was. A side shoot often grows from that node and flowers within a few months.
• If the stem has turned brown or yellow, cut it off close to the base. The plant will then put its energy into new leaves and roots, and send up a fresh stem later.

Cutting back to the base gives the plant a proper rest and usually a stronger flowering next time, so do that if the plant has few leaves or looks tired.

How to get an orchid to flower again

Most moth orchids will flower once or twice a year if they have enough light and leaves. The thing that triggers a new flower stem is a drop in night temperature. In autumn, a few weeks of nights several degrees cooler than the days, around 16°C, often does it. A windowsill in a room where the heating goes off at night is usually enough. If yours has not flowered for a year, the usual cause is a spot that is too dark or always warm.

Repotting

Repot every two years or so, after flowering, when the bark has broken down and stays soggy, or roots have filled the pot. Use orchid bark mix, never ordinary compost, and a pot only slightly bigger than the root ball. Trim off any dead roots (brown, mushy or papery) with clean scissors, keep the firm ones, and wait about a week before watering to let any damaged roots heal.

Orchid questions

How often should I water my orchid?

About once a week in summer and every 10-14 days in winter, but check the roots rather than going by the calendar. Water when they look silvery and the pot feels light.

Why are my orchid's leaves turning yellow?

One old leaf at the bottom yellowing now and then is normal. Several yellow leaves usually mean overwatering and root rot, so check the roots and the drainage. Yellow leaves with pale or brown patches can be sunburn from direct sun.

Why are my orchid's leaves wrinkly and limp?

The plant is dehydrated. Either it has been too dry, or, very often, the roots have rotted from too much water and can no longer take any up. Check the roots: firm and green or silver is healthy, brown and mushy is rot.

Should I cut off the orchid flower stem?

If it is brown, yes, cut it at the base. If it is still green, you can either cut above a node for a quicker second flowering or cut it at the base to let the plant rest and build up strength.

Are orchids safe for cats and dogs?

Moth orchids are listed as non-toxic to cats and dogs, which makes them one of the safest flowering houseplants for pet owners. See our guide to houseplants toxic to cats and dogs for the ones to avoid.

Can I put my orchid in normal compost?

No. Ordinary compost holds too much water and suffocates the roots, which rot quickly. Always use a chunky orchid bark mix.