My Oncidium is Not Blooming

Sunlight

• Flowering oncidium orchids need bright light. Any location that allows the plant to receive sunlight from above the plant rather than from the side will help with flowering. If growing in the house, a bright sunny window where the plant will get at least five to six hours of sun will encourage flowering. Once the orchid flowers, the plant can be placed in an area with more shade to protect the flowers. Oncidium plants prefer to be outside from June to October.

Temperatures

• Oncidium plants will tolerate night temperatures 10 to 15 degrees Fahrenheit lower than daytime temperatures. As the growing season comes to an end and the temperature difference narrows to less than 10 degrees Fahrenheit during the day and night, the plant needs to be placed indoors. Once brought indoors, keep night temperatures about 55 to 60 degrees Fahrenheit and raise the temperature at least 10 degrees Fahrenheit during the day. The oncidium needs the temperature change to thrive and flower.

Water

• Using a drainage tray underneath the oncidium indoors will provide the needed 50-percent humidity. The excess water from each watering will drain out the drainage holes and sit in the tray to provide the humidity. Outdoors, you won't need the drainage tray. The plant needs water when the bark mixture is dry just below the surface. If the plant is rootbound, growing in a bright light, it will need water every five days. Oncidium plants need moist medium, but not soggy, to thrive and flower.

Repotting

• Repotting is done once a year or when you see the rhizomes and roots protruding on the surface of the medium. Repotting is ideal after the flowers die or just after you see new growth on the plant. Use a commercial orchid potting mixture that has bark in it. The new container should be at least 1 to 2 inches in diameter larger than the old container.

Fertilizer

• Oncidium plants need fertilizer for flowering and growth. A well-balanced fertilizer, such as 20-20-20, will work well for orchids. Use 1 tsp. mixed in 1 gallon of water. Apply the fertilizer every two to three weeks throughout the year.