Orchids may appear to be exotic beauties, too fragile to survive anywhere but in some faraway jungle or in an expert’s greenhouse.
But fortunately that’s not the case for at least a few orchids that will thrive on the Central Coast. According to Larry Vierheilig, a Nipomo orchid hobbyist who has been growing orchids for 58 years, both phalaenopsis and oncidium orchids can be treated like ordinary houseplants, while cymbidiums flourish outdoors.
The trick to growing these orchids well is to choose healthy plants, then provide the proper doses of the same necessities — light, water and nutrients — that all plants require.
What to Look For
Healthy roots and leaves are key. Most orchids are epiphytes, which means that they cling to other plants or rocks and pull moisture and nutrients out of the air, rather than the soil. Their roots are easy to inspect, since they’re usually exposed in nursery pots.
Phalaenopsis, or moth orchids, bear large, rounded flowers that look somewhat like moths hovering along gracefully arching stems. Vierheilig said their round roots should feel plump and spongy. Their leaves should be firm and dark green.
Oncidiums bear upright sprays of dainty, speckled flowers. Their fine, hairy roots should be white, while their flower spikes should be sturdy and their leaves light green.
“The pseudobulbs, the little bulb things on the bottom where the leaves come out, should be firm and filled out,” Vierheilig said. “There shouldn’t be any wrinkling or pleating because that means they have not been watered properly.”
Cymbidiums bear tall, waxy spikes of large, traditional corsage flowers. Their roots and pseudobulbs should be firm and plump as well. Their long, strappy leaves should be slightly darker than light green, and their buds and flowers should line up uniformly along the flower spike, Vierheilig added.
At home, phalaenopsis and oncidiums need the same treatment: bright, morning light.
“If you have an east-facing window, just plain morning sun and no curtains,” Vierheilig said. “Place the plants about a foot back. They can get direct light, if it’s morning light. That would be ideal.”
Outdoors, cymbidiums tolerate direct morning light as well, but prefer bright, indirect sun or a little shade for most of the day.
“If you hold your hand several inches above a leaf, you would see a dark shadow on the leaf. It wouldn’t be like it would be in full sunlight, but somewhat a gray shadow,” Vierheilig said. “If you have a tree that has a somewhat open canopy, or you get little sparkles of sunlight through, or dappling on the ground, that’s great.”
But don’t plant your cymbidiums in the ground. They’ll rot. Instead, keep them in a pot that has plenty of holes to allow air to circulate through the roots and water to easily drain out.
Watering and Fertilizer
Repress any overwhelming urges to water your phalaenopsis, oncidiums or cymbidiums daily, or even weekly. And letting them sit in water is the kiss of death. Despite what you might think, these orchids do not need frequent irrigation. Instead, they like just a modicum of moisture.
“There’s an art to staying slightly moist,” Vierheilig said. “If I’m uncertain if a plant needs watering, I take a bamboo skewer and insert it down into the medium to the bottom of the pot. I wait about 10 minutes, then ease it back out and feel it. If it feels moist, I don’t water. If it feels like maybe a hint of moisture at the very end of it, then it’s time to give the plant a thorough watering.”
Vierheilig places his greenhouse orchids, one by one, in containers slightly larger than the pots that the orchids are growing in, then pours in water from a reverse osmosis system mixed with fertilizer. The orchids sit in the solution for 10 to 20 minutes. Once the planting medium is good and soaked, he pulls out the plants and lets them drain.
Vierheilig uses reverse osmosis to avoid subjecting his plants to hard water. He said distilled water or rainwater achieves the same result. If you go with regular tap water, he suggests every fourth watering to set the plants in your kitchen sink and run lukewarm tap water through them to leach out any salts that have built up.
As for fertilizer, he recommends applying one-quarter the recommended strength of any balanced, general-purpose product, such as a triple 15, triple 16 or triple 20, every time you water.
“You can use that year-round. You don’t have to switch between bloom and root and growth fertilizer,” he said. “But when you read the label, buy the one that has the least amount of nitrogen coming from urea. Urea takes bacteria to break down so the plants can use it. In a bark mix, there’s not a lot of bacteria. In a sphagnum moss, there’s even less.”
Bark or Moss?
Fir bark has been the dominant planting medium for years. It retains moisture while allowing ample air pockets for the roots. But many mass producers have shifted to sphagnum moss, and Vierheilig doesn’t like it.
“That’s not the easiest thing to grow them in, not for the beginner. It’s easy to keep it too moist. Then if it does dry out, it’s really hard to get it wet again,” he explained. “If I get one of those, after it’s bloomed, I usually pot it in a fir bark-perlite mix. It’s easier to judge whether it’s dry, moist or whatever. Plus, orchid roots like air. You get little air down there in that moss medium.”
It’s time to repot if roots are crowding out the top or squeezing through drain holes in the bottom. Wait until your orchid has finished flowering and new roots have begun to appear. Match the texture of the bark to the size of the roots: fine-textured oncidiums get fine-textured bark; coarse-textured phalaenopsis and cymbidiums get coarse-textured bark. Vierheilig mixes in perlite because the bark tends to break down with repeated watering.
Odds and Ends
With the most perfect of care, some Phalaenopsis orchids hold their flowers for four to five months on the Central Coast, Vierheilig said. He advises cutting off the spent flowering spikes completely. While some folks trim them to the first node below where the bud started, to force another spike, he believes that the technique weakens the plant.
While you can buy a greenhouse-grown Phalaenopsis in bloom just about any time of year, the natural bloom time is spring. To initiate flower spikes, the plants need two months of cool, night-time temperatures with swings of 20 to 25 degrees between nights and days, Vierheilig said.
“Take them outside in the shade at night, when it drops down to 50-ish. I bring mine back and forth every night. People are going to say, ‘Oh brother, I don’t want to do that.’ But if you want a nice flower spike with a lot of flowers, you have to put out a lot of effort there.”
Oncidiums like a dry rest after they finish blooming, Vierheilig said. Cut down their spent spikes, then stop watering for a couple of months.
“After that, ease back into a normal watering schedule, where it’s always slightly moist. They can get waterlogged very easily. You really want to watch the watering on those.”
Cymbidiums take a shorter rest after blooming, Vierheilig added. “But don’t let the medium stay dry for weeks on end.”
Cymbidiums also tolerate fairly cold night-time temperatures. However, if a freeze is expected, Vierheilig advises moving them into your garage or house.
Orchid Show This Weekend
Hundreds of blooming orchids will be on display at the 16th annual Central Coast Orchid Show & Sale, “Orchid Road Trip,” on Saturday, 9 a.m. to 5 p.m., and Sunday, 10 a.m. – 5 p.m., at the South County Regional Center in Arroyo Grande, 800 W. Branch St.
Orchid experts will answer questions, hold potting demonstrations and lead tours of the show. Vendors will sell orchid plants, books and supplies. Ellie’s SLO Down Cafe will offer coffee and lunch.
A preview reception on Friday, 6:30 – 9:30 p.m., will benefit the 5Cities Homeless Coalition.
Seeds of Wisdom
Rotate your windowsill orchids every few weeks. Otherwise, since the light is coming in from only one direction, the plants may begin to lean.
Visit Joan’s website at www.SantaBarbaraGardens.com, or post a comment by clicking on “Leave a Comment” back up at the top.