Dendrobium phalaenopsis (Cooktown Orchid)

Bloom Information

Dendrobium phalaenopsis hybrids typically bloom one to two times per year. Flowers last several weeks to several months depending on care. Bloom season often peaks in late winter or spring but may vary based on growing conditions.

How to Grow Indoors

(Indoor section is location neutral.)

Light

Provide bright gentle light for most of the day. An east or bright south-facing window with filtered light works beautifully. Too little light results in weak growth and fewer blooms.

Water

Water thoroughly when the potting mix is almost dry. These orchids prefer a wet and dry cycle. Avoid letting the plant sit in water. Use room-temperature water. If you live in an area with Hetch Hetchy water, it is generally safe to use.

Humidity

Aim for 40 to 60 percent humidity for steady growth. Average indoor household humidity is usually enough, though the plant will appreciate slightly higher levels during warm months.

Temperature

Warm growing conditions are ideal. Daytime 70 to 85 degrees and nighttime 60 to 70 degrees encourages healthy new canes and flowering.

Fertilizer

Feed lightly every two to three weeks during spring and summer with a balanced orchid fertilizer at half strength. Reduce feeding during fall and winter when growth slows.

Potting Mix and Repotting

Use a chunky orchid bark mix that drains quickly. Repot every two years or when the media begins to break down. Repot after blooming and when new growth appears.

How to Grow Outdoors in San Francisco

(Outdoor guidance is SF specific.)

Dendrobium phalaenopsis can grow outdoors in protected microclimates in San Francisco from late spring through early fall.

Outdoor Placement

Choose a bright spot with gentle morning sun and afternoon shade. Avoid direct midday sun, which can scorch the leaves. A covered porch or filtered light beneath a tree canopy works well.

Temperature Notes

These orchids prefer warm nights. Keep outdoors only when nighttime temperatures consistently stay above 55 degrees. Bring indoors during cold snaps or foggy stretches that push temps lower.

Watering Outdoors

Water slightly more often outdoors, especially on warm days. Ensure excellent drainage. Outdoor breezes dry pots faster.

Rain Exposure

Avoid prolonged exposure to rain. A quick sprinkle is fine, but repeated wet and cold conditions can cause rot.

Troubleshooting

Wrinkled canes
Usually underwatering or breakdown of old potting mix.

Black patches on leaves
Often sun stress. Move to gentler light.

No blooms
Increase light gradually and ensure the plant experienced a slight temperature drop at night.