Oncidium Care: Location, Watering, Fertilizing

Oncidium — the "Dancing Ladies Orchid" — produces dense yellow spikes with dozens of small flowers in the fall and winter. Robust, eager to bloom, widely available in commerce. Some hybrids are fragrant: Onc. Sharry Baby smells like chocolate, Onc. Twinkle like vanilla.

The genus was reorganized molecularly by Chase and colleagues in 2009 and 2015. Today, Oncidium s.str. comprises about 330 species — many former Oncidium species have been transferred to other genera (Gomesa, Trichocentrum, Lophiarella). In commerce and among collectors, the collective term "Oncidium Alliance" persists for the entire related group, including multi-generic hybrids (Burrageara, Beallara, Cambria, Vuylstekeara).

Location

Bright to lightly sunny — more light than Phalaenopsis, less than Cattleya. East window or shaded south window is optimal. Bright plant lamps also work.

Lack of light is indicated by dark green leaves and absence of flowering. Sunburn is recognized by yellow-red spots on the sun-facing side.

Watering

Oncidium stores water in the pseudobulbs. Allow to dry slightly before the next watering, but do not let it dry out completely.

• In summer every 5 to 7 days, in winter every 10 to 14 days
• Soaking preferred — 5 to 10 minutes in lukewarm water
• Pseudobulbs become wrinkled or show accordion-like folds on the new shoot with prolonged water shortage — this is a water shortage signal from the growth phase

Temperature and Rest Period

Oncidium needs a short, cool rest period after flowering, usually from October to March. During this time, water less, do not fertilize.

• Growth phase (April to September): 22 to 26 °C during the day, 17 to 20 °C at night
• Rest period (October to March): 16 to 20 °C during the day, 12 to 16 °C at night
• Outdoor summering: from June on terrace or balcony — partial shade, protected from heavy rain

Fragrant Hybrids — the Marketing Stars

Three commercially important fragrant hybrids:

• Oncidium Sharry Baby: dark red flowers with white lip edge, intense chocolate scent. Robust, eager to bloom.
• Oncidium Twinkle: Mini plant with delicate star-shaped flowers, light vanilla scent. Ideal for the windowsill.
• Oncidium Aloha Iwanaga: yellow spikes, light honey scent.

Substrate and Repotting

Pine bark medium (8–15 mm) for standard plants, fine (4–7 mm) for young plants and mini Oncidium. Repot every 2 years, directly after flowering. Substrate comparison · Repotting guide.

Frequently Asked Questions