Vivi's Orchid Corner

July 2003 - Volume 8, Issue 6

"Sun Protection"

Dear Orchid Friends:

Summertime is a wonderful time of the year. Outdoor activities beckon, vacation adventures delight and we put on hold the usual routines. We frolic carefree in the hot sun. Ouch, feel that burn. Don't forget the sunscreen!

The sun is intense during the summer months and high temperatures and bright sunshine can burn your orchids quickly. Orchids, like humans, require extra care during the summer. Orchids easily become parched, dry and suffer similar symptoms of sunburn. With higher temperatures, orchids require more frequent watering to prevent dehydration. It is easy to forget your orchids during the active summer months…gatherings, activities take precedence. But don't forget your orchids or they will suffer!

• Yellowing of plants and leaves
• Withering of leaves
• Leathery appearance to leaves
• Shriveled pseudobulbs
• Tips of leaves are browned
• Roots are dry, brittle and lack velamen
• Weak or mutant flower production

The amounts of light the orchids receive affect their color. A plant that is yellow or anemic green is getting too much sun. Orchids should be lighter green. Check your plants at various times of the day to determine the amount and intensity of sun exposure. The sun shines at different angles throughout the year. Summer angles are more direct and the sun is closer to the earth which boosts the UV light. The intensity of the UV rays may cause sunburn. Feel the leaves to ascertain their temperature. Leaves that are hot to touch are getting too much sun exposure and are susceptible to sunburn. Higher temperatures cause moisture loss which contributes to withering and dehydration. Observe whether your plants appear desiccated and leathery. Pseudobulbs may look dry with deeper folds. If so, your orchids are experiencing heat stress and burn.

• Move the orchids into a shadier location or change their location. If your orchids are housed outdoors, move them to shadier branches.
• Water more frequently and thoroughly wet roots and plant. Keep your orchids well hydrated. It may be necessary to water daily.
• Observe how much sunlight the orchids are receiving at various times of the day. Many orchids find the summer midday sun too intense.
• Provide good air movement. Air movement helps to cool the plant.
• Mist leafy plants daily to increase humidity and reduce the ambient surrounding temperatures.
• Spray surrounding benches, floors, ground to decrease the ambient temperatures.
• Consider using a shade cloth for extra protection.
• Have someone care for your orchids while you are away on Holiday or vacation.
• Notice how your environment may affect your orchids: have you recently trimmed back tree branches, removed a hedge, etc.

Sunburned orchids are in distress. Root and leaf tips brown off, flowers spikes shrivel and flowers may not be as full, strong or vibrant. Sunburned orchids are susceptible to infestation and disease. Be especially alert for scales on the pseudobulbs and undersides of cattleya leaves. Viruses are more apt to invade when orchids are stressed. Sunburned orchids take a while to rebound. Thus, take care with fertilizers as this may burn orchids even further. Fertilizer salts are hard on dehydrated plants.

Protect your orchids from the blazing sun. It is worth the extra effort to have healthy plants. Water and shade are their sun block protectors. Just as you reapply sunscreen throughout the day and hydrate, be sure your orchids are protected as well. Enjoy the summer activities and your orchids. But don't forget the sunscreen!

Vivi