Moth orchid care guide

The moth orchid is the orchid sold at every grocery store. Its flowers last for months, and it blooms again every year with the right care. It grows on trees in the wild, not in soil. That one fact explains most of its care.

Light

Give it bright, indirect light. An east window is ideal. A north window works. A south or west window needs a sheer curtain.

Healthy leaves are medium green. Dark green leaves mean too little light. Yellow-green or red-tinged leaves mean too much.

How to water an orchid

Water when the bark is almost dry. Look at the roots through the clear pot. Silver-gray roots are dry and ready for water. Green roots are still wet.

1. Take the plastic pot out of the decorative pot.
2. Set it in a bowl of room-temperature water for 10 to 15 minutes.
3. Let it drain all the way. No water should sit in the cover pot.
4. Keep water out of the crown, where the leaves meet. Dab it dry if water lands there.

That is about once a week in most homes. Some stores sell orchids with ice cube directions. A full soak wets every root, so it works better for most people.

Soil and potting

Moth orchids grow in orchid bark or sphagnum moss. Potting soil smothers the roots.

Repot every one to two years after it blooms, when the bark breaks down or roots fill the pot. Trim any brown, mushy, or hollow roots. Set it in fresh bark in a clear plastic pot with holes. See how to repot a houseplant step by step.

Aerial roots

Roots that grow up and out of the pot are normal. They take in water and air. Leave them be. Do not cut healthy aerial roots or force them into the bark.

Humidity and temperature

Average room air is fine. More humidity keeps the flowers fresh longer.

Keep it between 18 and 29°C (65 and 85°F) in the day. Keep it away from cold windows, drafts, and heat vents.

Feeding

Feed every two weeks with orchid fertilizer at half strength while the plant grows new leaves or roots. Flush the pot with plain water once a month to rinse out salts.

After the flowers fall

You have two choices once the last flower drops.

• Cut the spike above a node. Find the second node below the lowest flower and cut 2 cm (1 in) above it. A side spike may grow from that node and bloom in a few months.
• Cut the spike at the base. The plant rests and puts its energy into new leaves and roots. It blooms again next year, often with a stronger spike.

A spike that turns brown or yellow is done. Cut it off at the base.

Getting it to bloom again

Moth orchids set new spikes after a few weeks of cooler nights in fall. Nights 5 to 8°C (9 to 15°F) cooler than days do the trick. A spot near a cool window in October and November works well in most Canadian and northern US homes. Keep the leaves off the cold glass.

New spikes look like a root with a mitten-shaped tip. Stake the spike as it grows, and do not turn the pot once buds form.

Propagation

Sometimes a baby plant, called a keiki, grows on the flower spike. Wait until it has two or three leaves and roots 5 cm (2 in) long. Cut it off with a bit of spike and pot it in small bark.

Problems

What you see	Most likely cause
Wrinkled, limp leaves	Too dry, or roots rotted and cannot take up water
Brown, mushy roots	Too much water or old, broken-down bark
Lowest leaf yellows and falls	Normal aging, one leaf at a time
Buds drop before opening	A move, a draft, or ripe fruit nearby
No new spike for over a year	Not enough light, or nights too warm in fall
Black, wet spot in the center	Crown rot from water left in the crown

Pests

Mealybugs and scale hide under leaves and on flower spikes. Dab them with rubbing alcohol on a cotton swab. Fungus gnats can live in old, wet bark. Read how to get rid of fungus gnats in houseplants.

Pet safety

The ASPCA lists moth orchids as non-toxic to cats and dogs. They are a safe flowering plant for a home with pets.

Varieties

• Standard moth orchids have spikes 60 to 90 cm (2 to 3 ft) tall.
• Mini moth orchids stay small, with spikes about 30 cm (1 ft) tall.
• Multiflora types grow several branching spikes with smaller flowers.
• Spotted, striped, and two-tone flowers are common.
• Blue moth orchids are dyed. Their next flowers come in white.