• Orchids with pseudobulbs are entering dormancy. If they sport swollen stems like those in the first photo below, they may only need water once or twice per month over winter. Too much water can cause rot, or mess up the plant’s flowering schedule. Cut back on fertilizer, too.
• Orchids without pseudobulbs, like Phals, Paphs, and Masdevallias, don’t go dormant. However, with seasonally lower light levels and cooler temps, it’s best to reduce their water and fertilizer slightly.
• All orchids need good humidity, but home and office heating can dry the air like an arid desert. Low humidity can cause blooms to wilt, and invite pests like spider mites, mealybugs, and scale. Find helpful tips to raise humidity here.
• Consider adding extra light to compensate for the weak winter sun.
• Members of the Cattleya family, like the red and yellow hybrid in the second photo below, may be affected by too many hours of artificial light. They require long, dark nights to trigger flowering. Keep them away from any artificial light at night.
• Remove dead leaves or flowers. This helps limit hiding places for unwelcome pests or disease.
• Don’t panic if a few older leaves wither and drop. Some varieties of Dendrobiums, like the cool grower in the final photo below, lose all their leaves. Other types, like Cycnoches, Epipactis, and Thunia, are also deciduous. Continue to give them bright light and good humidity. Water when their pseudobulbs start to shrivel, only once or twice per month.

One trick to help Cymbidiums bloom is to give them nightly temperature drops of 15-20°F (8-11°C,) especially in autumn. Without this day/night temperature difference, they won’t form flower spikes. Here on the coast, they can grow in full sun. However, growers in warmer areas should provide morning sun and afternoon shade. Plants need enough light so that leaves are light green, not dark green. Cymbidiums enjoy regular fertilizer, and they love compost. They can survive a light frost, although temps below freezing usually damage flowers.

For orchid growers in warmer climates, miniature Cymbidiums like warmer temps. These small varieties are best for growers where summertime temps stay above 70°F (21°C) at night.

• Bring warm growers indoors before temps fall too much. Take the opportunity to remove any leaf or flower debris. Check for pests, paying attention to leaf undersides and the potting media. A little prevention now can save a lot of headaches later, so I always spray with insecticidal soap before bringing orchids inside.
• Increase light levels to compensate for fall’s weakening sunlight and shorter days. Consider adding artificial light as a supplement. For all varieties, even lower-light Phals and Paphs, providing some direct morning sun can keep them happy until spring. Make any light increase gradually over 2 weeks to avoid burning leaves.
• As home and office heating systems switch on, they dry the air. Pay extra attention to maintaining high humidity. Dry air invites pests.
• Many orchids are moving into a dormant stage. Slowly reduce watering for Cattleyas, Cymbidiums, Dendrobiums, Epidendrums, Miltonias, Odonts, Oncidiums, Vandas, and any other variety with pseudobulbs. Begin to cut back on fertilizer as well.

To grow this variety, place in bright light with some direct sun. Water every other day (more if it’s warm,) and keep in cool, breezy conditions. They enjoy regular fertilizer or a good dose of compost. Keep them drier during winter dormancy.

This species is native to the Andes of Peru, Ecuador, and Colombia, where it grows at elevations up to 10,500 ft. (3200  m.) At those dizzying heights, it’s no surprise that it prefers temps below 80°F (27°C.) It can survive freezes down to 25°F (-4°C,) but it’s best to avoid such cold temps for plants in cultivation.

Don’t let Cyrtochilum’s name scare you; pronouncation is easier than you might think. Say “sear tow KYE lum” to rhyme with “dear go by him.” Botanists have been debating this beauty’s place in the orchid family tree for years, so it’s sometimes labeled as an Oncidium.

This species is native to elevations of 8000 – 9000 ft. (2438 – 2743 m.) from only a single valley near Cochabamba, Bolivia. That’s the largest city in Chapare Province, which provides the species name Masdevallia chaparensis. Its cloud forest home in that narrow band of the Andes is similar to this mild climate about 5 miles from the Golden Gate. Since there’s no rain here during summer, I water daily until winter rains resume. It loves a good shot of compost, but growers who use artificial fertilizers should only use weak doses.

By the end of May, San Francisco’s rainy season has usually given way to the dry season, but this year’s weather seems anything but typical. Fortunately we’ve had nothing like the violent storms in other parts of the country. Instead, a cool, wet spring is keeping the garden well hydrated. The light rains and mild temps have eased my watering duties, allowing me to concentrate on other seasonal chores:

• The end of winter dormancy means regular and thorough watering. Cymbidiums, Paphs, Masdevallias, and Miltonias need daily watering, but for others, there’s no single formula for how often to water. New leaves and roots, longer hours of light, and warm days all require extra water.
• Only the most sun-loving Vandas and Epidendrums should remain in direct midday or afternoon sun. Many orchids will enjoy morning sun. All need extra shade during hot summer days.
• Fertilize regularly. Standard orchid advice is “weakly, weekly,” which means a dilute solution repeated on a regular schedule.
• Most orchids need repotting every 2 – 3 years. Spring is the ideal time, as flowers fade and new leaves and roots start to grow. Check here to see if you need to repot your orchid.

• Overwatering — This is a quick, easy, and common assassination method. Excess water rots the potting media, and eventually suffocates the roots. To speed things up, allow the flower pot to sit in a tray of water. This will quickly cause the orchid roots and potting media to rot. Death within a week. The tray of water and rotting roots may stink and attract flies, so you get a bonus.
• Underwatering — Just forget to water. This method is very effective, however, during winter dormancy it may take months for orchids with pseudobulbs to die. If you’re trying to escape suspicion, you may want to dribble a few drops on the plant. Whatever you do, do not give the plant and potting media a thorough soaking, even if water runs out of the holes at the bottom of the pot. This will greatly delay death by underwatering.
• Temperature extremes — It’ll help to identify your orchid so you know its proper temperature range. Armed with that knowledge, you can be creative. Open a window next to a Phal when it’s near freezing outside. Keep a Masdevallia in a warm kitchen (closer to the stove is better.) Place an orchid next to a heating vent which is blasting hot air. Take a warm grower, like a Vanda, and stick it outdoors in Calgary in February.
• Strong sunlight — While this may have no effect on some varieties like Vandas or Cymbidiums, except to make them bloom, direct sun will burn Phals, Paphs, Masdevallias, and Miltonias. It works best in summer, but may not work at all in winter. Modern car windows filter some sunlight, but the added bonus of the car heating up in the sun can kill an orchid during the time it takes to do a little shopping, or eat lunch. It’s multitasking.
• Low light — This is your best option if you want a very slow death for Phals and Paphs, since they tolerate some degree of low light. For Cymbidiums, Dendrobiums, Oncidiums, and Vandas, it will be quicker, since they need bright light or full sun to thrive. When you want to kill by low light, find a dark corner, and place the orchid victim in it. Keep it away from any windows. Do not supplement its light in winter. Some orchid varieties may surprise you by lasting for months or even years in low light. Don’t worry; they won’t bloom before they finally perish.
• Stale or dry air — Stale, stuffy air can cause health problems for both people and orchids, so if you choose this method, you probably shouldn’t spend too much time with your victim. Stale air encourages nasty microorganisms and pests, and they’ll overwhelm your orchid eventually. To cut off air movement, lock the plant in an unused room, or overcrowd it with other plants. Keep it away from fans or windows. Dry air will quickly make flowers drop, and wilting leaves will soon follow. Dry air also invites pests, especially spider mites. Do not provide humidity or good air movement, or you’ll drive the pests away. If you don’t have dry air already, heating and air-conditioning systems usually dry the air efficiently.
• Too much fertilizer — A single excessive fertilizer dose can burn an orchid’s roots and leaves, but probably won’t kill it. Rather than the orchid maxim “weakly, weekly,” which teaches that orchids prefer a weak nutrient solution, try “fertilize forcefully.” Heavy doses of fertilizer given at frequent intervals will stop that orchid from ever bothering you again.

Autumn arrives in the Northern Hemisphere with a chill, shorter days, and some orchid chores. As temperatures drop, bring warm growers inside. Remove any dead leaves or weeds. Check for pests, especially those hiding on the undersides of leaves. I spray orchid plants and potting media with mild insecticidal soap or rubbing alcohol before bringing plants indoors. Many growers use Neem Oil or other insecticidal oils, which have the advantage of protecting leaves for several weeks.

If your Phals aren’t in bloom, cooler nighttime temps can initiate flower spikes. Cymbidiums also respond to cooler nights with new flower spikes. Most varieties won’t bloom if they’re kept too warm at this time of year.

Users of high nitrogen fertilizer, like 30-10-10, should switch to a low nitrogen formula, like 10-30-30. No matter what fertilizer you use, start to taper off with weaker solution or less frequent doses. Many orchids are heading into dormancy. Start to reduce watering for orchids with pseudobulbs, like Cattleyas, Cymbidiums, Dendrobiums, Epidendrums, Miltonias, Odontoglossums, Oncidiums, and Vandas. Good humidity is always necessary, especially to counteract the dry air of home and office heating.

If lower leaves turn yellow or drop, don’t panic. Some Dendrobium varieties will completely shed their leaves in the next couple months, but they’re just dormant, not dead. Continue to give them bright light and good humidity, and they’ll come back to life in the spring.

Also known as the False Ladyslipper, the Stream Orchid is not an air plant. It’s a terrestrial orchid that lives in moist soils along streams, on cliff faces, and in mountain bogs. The plant dies back during winter, and re-emerges from underground tubers the next spring.

Many terrestrial orchids are difficult to grow, requiring highly specialized conditions (yet another reason why you should NEVER remove wild orchids from their natural homes.) However, Epipactis gigantea is relatively easy to cultivate, and adapts to a wide range of conditions. I keep mine in regular potting soil, and keep the pot in a tray of water so it never dries out. It loves a good dose of compost fertilizer, which has helped my plant grow into a vigorous specimen. Certainly it seems right at home.

Nectar spurs are long, narrow tubes with a drop of nectar at the bottom, and they’re good clues that this orchid is fragrant. One arcs down behind each flower. During daytime, it has little scent, but starting in the evening, it puts out a strong fragrance that reminds me of tuberose.

Related to Darwin’s Orchid and Oeoniella, Jumelleas can grow into large, attractive plants. The leaves form a fan pattern, and healthy specimens can grow 2 ft. (0.6 m) tall. Jumelleas enjoy conditions like Dendrobiums, with bright light, regular water and fertilizer, and winter dormancy.