When it comes to getting orchids to flower, it always comes down to the water.
“Orchids come from a clean, pristine environment, and they need water as pure as rain; they thrive on that,” said Roy Tokunaga, an orchid grower since 1971 and co-owner of H&R Nurseries in Waimanalo. High elevation, morning dew and high humidity are also ideal, he added.
A specialist in Dendrobium orchids, Tokunaga is a frequent lecturer nationally and is a respected judge of plants for the Honolulu Orchid Society and the American Orchid Society. As a member of four Oahu orchid societies, he usually talks about how to be a better grower in different weather conditions. The most common question he gets from home gardeners: Why don’t my orchids bloom?
Usually it’s because of two extremes. People either water the orchids too much so the roots rot, or they don’t water thoroughly enough and the roots dry out. The type of water and its application are the most important — one size does not fit all.
“I wish it was simple, but it’s not,” he said.
Most people rely on water piped in from the city water system. They just wet the plant down briefly instead of letting the water drain out of the pot, but the danger in that lies in the accumulation of salt minerals, found in the water, on the roots and the pot, leaving a telltale white residue.
“You never see (the residue buildup) coming. It’s so gradual, but once the roots are compromised, they can’t pick up proper nutrition. The plant never performs well, and it doesn’t flower,” Tokunaga said. “It’s the salt! That’s the problem.”
The solution is to water longer and allow the excess to drain out. Let the plant dry out for a couple of days, then repeat the watering. For indoor orchids, take it to the sink for a thorough watering, and allow it to drip out before returning it to the display area, he said.
To complicate matters, everyone’s water source and climate are different, and levels of salt in the city system are higher in various parts of the islands, Tokunaga said. To make it simple for those with just a few orchids indoors, Tokunaga recommended buying bottled distilled water — just a light application once a week; there’s no need to allow the water to drain out.
This inexpensive solution worked well for his daughter, who lives in a mainland apartment with the challenges presented by air conditioning or electric heating, depending on the season. (Those filtered drinking water pitchers won’t work because they don’t deionize the water, he said.)
Hobbyists with larger orchid collections that are mostly kept outdoors often use a reverse osmosis water filter to remove ions like the salt minerals. Prices on the simplest water systems start at $125 to produce 100 gallons a day, but can go quite high depending on how many gallons per day are needed.
“The reverse osmosis is for serious growers who want the best for their orchids. We grow the plants for competition and money. A few hobbyists grow special orchids that can only survive on rainwater. Several of them are my lifelong pets,” said Tokunaga, who has long grown many hybrids from seeds in his laboratory. He fondly calls these favorites “pets” because he said he gets personally attached to the plants from giving them constant attention over the years.
The use of rain or reverse osmosis water will extend the life of the potted plants and the flowers will bloom longer. Rainwater is the cheapest, the best and has always been encouraged by the Board of Water Supply. It’s not easy to collect, though it sounds simple, he said. It takes a few hardware supplies to divert water from a gutter into holding tanks, and there can be problems with mosquitoes, ocean salt spray on the roof, or seasons without rain.
“It always goes back to the water,” he said, no matter the water source or climate. The trouble and expense are, however, worth it to avid growers who spend thousands of dollars a year on their orchids to get them to produce larger blooms more frequently and with more disease resistance.
“You can’t put monetary value to the pleasure plants give when they perform,” he added.
IMPORTANT ORCHID TIPS
>> Fertilize lightly: Tokunaga recommends Island Supreme Orchid Special fertilizer, which sells for about $18 for four pounds in most garden stores, with a 13-2-13 NPK (nitrogen, phosphorus, potassium) ratio of macronutrients. Dissolve 1/2 teaspoon per gallon of water; fertilize once a month for indoor and outdoor plants, and more often in the summer depending on the amount of sunlight outdoor plants receive.
>> Doses of sunshine: Most orchids prefer semi-shade under trees, about 50% to 70% shade for four to six hours a day. Tokunaga takes his indoor orchids outside, even while in bloom, for a couple of days of sun after sitting in the house for a week.
“I feel orchids are solar powered and need recharging after a week,” he said, though if this isn’t possible, indoor plants would do best near southern windows.
Is there a gardening topic you’d like to read about in the Garden Variety column? Email Pat Gee at pgee@staradvertiser.com with your request.
