Keep your orchid happy

Repotting made easy

Adrian Higgins / The Washington Post /

Buying a moth orchid

Orchids can become stressed if mishandled or improperly kept. Orchids in grocery stores tend to be too cold and displayed close to produce. Nearby apples, bananas or other fruit give off ethylene gas, which causes the orchid blooms to age prematurely.

Look at the plant's general health and for fleshy, live roots. The leaves should be green, turgid and the central growth stem upright. Avoid plants with yellowing tips to the flower stem or with buds that are falling off. Choose an orchid that has begun to flower, not just in bud. When stressed, the buds will be small or fail to open.

Repotting

Moth orchid roots are meant to wander out of the pot. But if the plant is potbound at the base or if the growing mix has broken down and smells musty, repot the plant. This is best done after flowering in late spring.

Remove all the old mix, cut off shriveled, dead roots and use fresh mix. The roots should occupy about three-quarters of the volume of the new pot, typically about an inch bigger in diameter than the old pot. Placed in a pot that is too big, the orchid will suffer root rot. If your orchid is part of a larger florist's arrangement, wait for the plant to finish flowering and then pot it individually in a container of the correct size.

Moth orchids do not grow by rhizomes and do not need to be divided like other orchids.

Temperature

Typical room temperature is fine, but go no lower than 60 degrees. Raising humidity in winter is a boon to orchid and orchid grower alike, but correct watering is more important than high humidity. Misting is unnecessary and may damage the blooms.

Light

Moth orchids like bright, indirect light. Direct sunlight will turn the leaves pale green or yellowish green and stress the plant. Insufficient light will cause the upper leaves to be smaller than the ones below them — they should be larger.

Watering

Forget the dainty watering can. Take the orchid to a sink and run water through the pot thoroughly. This will saturate the medium and wash out old fertilizer salts. Test dryness with your finger and learn to judge the watering need by the weight of the pot.

Repotting made easy

1: To repot an orchid, first look for constricted roots and moss that has broken down into a mass.

2: Remove the old moss by hand, wearing gloves. Dead or dried roots can be cut off; take care not to damage healthy roots.

3: Place a clump of fresh sphagnum peat moss beneath the plant before repotting.

4: The new pot should be an inch or so wider than the old one. Fill spaces with fresh moss, then water the orchid.