Orchid
Orchids (family Orchidaceae) are one of the largest families of flowering plants, spanning more than 25,000 species and countless hybrids. The group includes epiphytes that grow on trees, lithophytes that cling to rocks, and terrestrials that grow in soil. For home growers in the United States, the most common orchids are Phalaenopsis (moth orchids), Cattleya, Dendrobium, Oncidium, and Cymbidium. These modern hybrids are bred for dependable bloom cycles, longer-lasting flowers, and tolerance of typical indoor conditions. Because care varies by genus, this profile gives practical ranges and notes the most important exceptions so you can adjust with confidence.
🌱 Taxonomy and origin
Orchids occur on every continent except Antarctica, with centers of diversity in tropical Asia and the Americas. Many houseplant orchids descend from species native to warm, humid forests where they anchor to tree bark and receive bright but filtered light and regular moisture with fast drainage. Hardy terrestrial orchids occur in temperate regions, including the North American lady’s slipper group (Cypripedium).
🌸 Bloom time
Bloom timing depends on the group. Phalaenopsis typically flower from late fall to spring and can hold blooms for two to three months. Cattleya often bloom in spring to fall with showy, fragrant flowers that last two to four weeks. Oncidium can flower once or twice a year, often in fall. Cymbidium spike in winter to early spring and last three to six weeks. Cooler nights and a modest day to night temperature drop help set buds in many genera.
📏 Height and spread
Most indoor orchids grow 8 to 36 inches tall including their flower spikes. Phalaenopsis leaves form a low rosette 8 to 18 inches wide, with arching spikes up to 30 inches. Sympodial orchids such as Cattleya and Oncidium form clumps of pseudobulbs that slowly enlarge to 12 to 24 inches across over several years. Cymbidium can reach 2 to 4 feet with strappy leaves.
☀️ Light
Bright, indirect light is the baseline. Place Phalaenopsis near an east window or a shaded south window where the leaves look medium green. Too little light gives very dark leaves and no flowers. Too much light causes yellowing or reddish patches. Cattleya, Dendrobium, and Oncidium accept stronger light, even gentle morning sun. Cymbidium need the brightest light of the common groups and can grow outdoors in light shade in mild climates.
💧 Water
Water thoroughly, then let the potting mix approach dryness before the next watering. Most indoor orchids prefer a three to seven day rhythm depending on season, pot size, and airflow. Use room temperature water and avoid letting water sit in the crown or between leaves. Flush monthly with clear water to reduce fertilizer salts. Consistent overwatering is the main cause of root rot
🌍 Soil and pH
Use an orchid mix that drains fast and holds air around the roots. Typical ingredients are medium-grade fir bark or pine bark, sphagnum moss, perlite, and charcoal. Many mixes test slightly acidic, roughly pH 5.5 to 6.5, which is suitable for epiphytic orchids. Terrestrial orchids need a fine, humus-rich, well-drained mix. Never use regular garden soil in a pot.
❄️ USDA hardiness
Most popular indoor orchids are grown as houseplants and are not assigned outdoor hardiness zones. A few terrestrials are hardy in the ground: Bletilla striata in zones 5 to 9 with mulch, and many Cypripedium hybrids in zones 3 to 7 with excellent drainage and protection from hot summer sun. Cymbidium tolerate light frost and can summer outdoors in zones 9 to 10.
🌼 Propagation and longevity
Sympodial orchids divide easily. When a clump has 6 to 10 pseudobulbs, separate healthy fans with at least three pseudobulbs per division and repot in fresh mix. Phalaenopsis sometimes produce keikis, which can be removed once they have several roots 2 to 3 inches long. Seed propagation requires sterile lab conditions and is slow, taking years to reach flowering. With steady care, modern hybrids live for decades and improve with each repotting cycle.
👃 Fragrance
Fragrance ranges from none to intense. Many Cattleya and some Oncidium and Dendrobium lines are notably fragrant during the day. Phalaenopsis are often lightly scented or unscented, though exceptions exist. Scent strength can vary by temperature and time of day.
⚠️ Toxicity and pet safety
Orchids used as houseplants are generally considered non-toxic to cats and dogs, including Phalaenopsis. Ingestion may still cause mild stomach upset, so place plants out of reach and avoid using pesticide sprays where pets might lick leaves. Keep floral wires, clips, and stakes away from children and pets.
🌿 Vase life
Cut cymbidium spikes last 2 to 3 weeks with clean water, cool rooms, and a trim of the stem every few days. Phalaenopsis sprays often last 1 to 2 weeks. Keep cuts away from direct sun and ripening fruit, change water regularly, and use a commercial flower food for best results.
🐛 Pests and diseases
Common pests include mealybugs, scale, aphids, spider mites, and thrips. Inspect leaf axils, undersides, and the junction of roots and bark. Start with mechanical removal and insecticidal soap or horticultural oil, repeating weekly until clear. Root rot, bacterial soft rot, and leaf spots arise from poor drainage or stagnant air. Remove infected tissue, improve airflow, and adjust watering. Viral diseases cause distorted growth and mosaic patterns and are not curable; discard infected plants to protect the collection.
Orchid Flower FAQs
How often should I water an orchid?
Water when the mix is nearly dry. In most homes this is every three to seven days. Lift the pot: it should feel light. Roots should look silvery green between waterings and bright green right after you water.
Why is my orchid not blooming?
Insufficient light is the top reason. Move the plant to a brighter spot with filtered sun and ensure a day to night temperature drop of about 5 to 10°F. Avoid excess nitrogen and repot if the mix has broken down.
Do orchids need special pots?
Any pot with generous drainage works. Clear nursery pots help you see root health and moisture. Decorative cachepots are fine as long as water cannot pool at the bottom.
When should I repot?
Repot every 1 to 2 years, or sooner if the bark breaks down, roots crowd the pot, or the plant wobbles. Best time is just after flowering when new roots begin.
Can I grow orchids outdoors?
Yes in mild climates and during summer in many regions. Provide bright shade, good airflow, and bring plants inside before nights drop below 50°F (10°C).
Leaves are wrinkled or accordion-like
Usually erratic watering or very low humidity. Water thoroughly and stabilize your schedule. Increase humidity with a tray of pebbles and water, without letting the pot sit in water.
Roots are brown and mushy
Classic overwatering and exhausted mix. Trim dead roots, repot in fresh bark, and water less often. Ensure the pot and saucer cannot hold standing water.
Buds turn yellow and drop
This is bud blast. Causes include sudden temperature swings, drafts, or ethylene gas from ripening fruit. Move the plant to a steadier spot away from the kitchen.
Sticky residue on leaves
Likely sap from scale or aphids. Wipe leaves with a damp cloth, then treat with insecticidal soap or oil. Repeat weekly for several cycles.
Interesting tips
- Aim for 10 to 20°F cooler nights in fall to encourage spikes on Phalaenopsis and Cymbidium.
- A small fan on low near, not at, the plants improves bud set and reduces disease pressure.
- Fertilize weakly, weekly during active growth using a balanced orchid fertilizer at one quarter strength.
- Use rainwater, distilled, or filtered water if your tap water is very hard to prevent salt buildup.