Humidity

• Oncidiums such as the Twinkle Star don't need as much humidity as other orchids. Thirty to 60 percent humidity is sufficient, according to the University of Tennessee's "Growing Orchids in the Home." As showers can increase humidity levels in the bathroom to 70 percent or more for several hours, bathrooms may give Twinkle Star orchids too much humidity.
  
  

Problems with Steam

• Bathroom steam is beneficial for some orchids, but too much humidity can lead to fungal diseases. This is especially true if you shower at night, increasing humidity levels before leaving Twinkle Star orchids in the dark, unable to dry. Wet foliage may then lead to fungal growth or rot. Air flow helps prevent these problems, but only bathrooms with windows receive air movement.
  
  

Other Factors

• As Oncidiums, Twinkle Star orchids require more light than other orchids, and bathrooms tend to be too dark. Oncidium orchids need at least one full hour of sun a day, but several hours in a brightly-lit window is healthiest. The University of Tennessee recommends a south-facing window. Twinkle Stars also need to dry thoroughly between waterings; steamy bathrooms prevent this.
  
  

Alternatives to the Bathroom

• Instead of placing your Twinkle Star orchid in the bathroom, you can increase humidity to lower, healthier levels by placing it near a humidifier or on a tray filled with damp gravel. You can also place it in a room next door to the bathroom, letting it soak in the secondhand bathroom steam as it drifts out of the bathroom. To avoid fungal disease or rot, water or mist the Twinkle Star in the morning and let it dry by nightfall.