Why did my Vanda orchid suddenly become weak this fall?
Vanda are native to humid forests in tropical Asia. They are epiphytic plants, that is to say they grow in fast-draining pockets of debris on trees. Vanda and related orchids are adapted to warmth, moisture and strong, filtered light with loose, fast-draining, growing medium.
Sudden decline in late fall is not uncommon in the northeast. As the hours of daylight shorten and the air is increasingly cold and dry, it becomes difficult to maintain natural light and humidity levels that fall in in the orchid's comfort range. Test the light and humidity in the environment and re-establish the correct equilibrium of light, humidity, warmth and nutrition, using a humidifier and supplemental artificial light if necessary. Continuing to water generously without adequate light can overwhelm the plant and lead to root and stem rot.
Your Vanda orchid needs:
- extended bright to very bright light to remain vigorous and produce flowers. In the New York City area, a south-facing window is best for all Vanda types.
- a minimum of 65% relative humidity, whereas an average home in the northeast may have humidity as low as 25%. You can use a simple hygrometer to assess the humidity and keep it in the 70 to 80% range that Vanda prefers. Vanda may fail to flower without adequate humidity.
- generous water at its roots and may be watered as often as daily if air circulation is good (for instance plants grown with exposed roots). From November through February, be sensitive to the change in light your orchid is receiving and reduce watering accordingly.
- day temperatures between 70 and 85°F., with night temperatures between 60 and 70°F. all year long.
- balanced, powdered fertilizer (20-20-20), at ¼ to ½ of the recommended strength on the label, every time you water. Reduce frequency in the winter. Occasional feeding in summer with a high-phosphorous, organic fertilizer will support flowering.
For complete care information, see our Guide to Vanda Culture.
Courtesy of NYBG Plant Information Service
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