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Getting Ready for Winter

Getting Ready for Winter

Marilyn H.S. Light
Adapted from material first published at in September 1998

There are few places on Earth where the climate is unchanging year round. Even in the tropics, there are usually wet and dry seasons and times when the weather is either cooler or hotter than average. Those of us raising orchids in temperate climes inevitably have to deal with winter which may be very or not so very cold, damp or dry, but always with shorter days and weaker sunlight. We want to ensure that our orchids are healthy going into this season and that they emerge at the end, robust and ready to take advantage of the lengthening days and summer.
I - For those hobbyists having plants outdoors and intending to bring them indoors:
1 - Make sure that the orchids are as healthy as possible before bringing them indoors.
2 - Check for slugs, sow bugs, earwigs and similar pests which could damage orchids.
II - For those hobbyists who maintain their orchids indoors year round either on a window sill, under lights or in a greenhouse:
1 - Give your orchids a 'fall check-up'. Divide, re-pot, cull as needed. Look for pests that may have flourished while you were on summer vacation.
2 - Identify pests and treat as required. Employ 'indicator' plants such as Patience Plant (Impatiens) to become quickly aware of spider mite infestations if they occur.
3 - Adjust watering and fertilizer schedules to accommodate reduced light, lower humidity as appropriate.
4 - Reduce the frequency of fertilization or stop fertilizer application altogether if plants are becoming dormant.
5 - Monitor temperature, humidity and air movement in all parts of the growing area. Beware of stagnant air pockets.
6 - Examine your collection at least weekly for signs of disease and pests. Have a 'hospital bench' to isolate sick plants.
7 - Protect orchids against sudden changes in temperature and humidity. Shelter cold-sensitive plants from cold condensation droplets falling from a greenhouse roof or from hot and cold drafts.
8 - Increase or supplement light to maintain plant vigour.
9 - Day length affects many orchids, triggering them to either bloom, grow or rest. Vary the artificial day length in harmony with the season; 8-12 hours in winter versus up to 16 hours in summer. Verify that windowsill or greenhouse plants are not being illuminated by outdoor or indoor lights at night during winter since this may interfere with their growth pattern.
9 - Lay down a supply of rain water or use another source of mineral-free water for winter use.
10 - If using a gas heater, verify that it is vented properly. Install an alarm system to guard against heater failure. Have the heater checked annually to forestall crises. Plan for a back up if sudden loss of power or heater breakdown will put your collection at risk.

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