The National Garden Bureau, a non-profit organization established to promote gardening, has chosen orchid as its houseplant to promote in 2023. Thus, we now are in the "Year of the Orchid," at least from the perspective of the National Garden Bureau.
When it comes to adding orchids to your houseplant collection, the familiar adage "the fear of the unknown is the greatest fear of all" seems appropriate. Most people consider orchids to be exotic, delicate plants with care requirements well beyond their ability. While some orchids can be challenging, others are not that difficult to maintain and, certainly, are worth the effort.
Orchidaceae, the plant family to which orchids belong, is a diverse and widespread group of flowering plants with exotic blooms that are colorful and often fragrant. Native to every continent except Antarctica, orchids comprise one of the largest families of flowering plants. With more than 28,000 species, there are more orchids species on earth than mammals and birds combined. The first key to success with orchids is to know what type you are growing.
Orchids can be divided into two main types: epiphytic and terrestrial. Most orchids are epiphytic and, in nature, attach themselves to tree branches and take in nutrients from decaying bark and tropical rains. They do not harm their host plant. Epiphytic orchids typically form "pseudobulbs' which are plump, elongated structures just below the leaves. They serve as both as a food and water source for orchids that experience a period of unfavorable weather in nature.
Alternatively, terrestrial orchids anchor themselves in the ground in nature and have root systems more akin to other houseplants. However, terrestrial orchids still prefer a porous, well-drained potting medium, but with greater water retention than potting media used for epiphytic orchids.
Another means of orchid classification is by their growth pattern. Most orchids (e.g., cattleya) are sympodial meaning they grow "sideways" and put on new growth that is a duplicate of the segment before it. Conversely, orchids with a monopodial growth pattern (e.g., phalaenopsis) grow upward and continue to get taller with age.
For the greatest success in growing an orchid, it is advisable to learn about its natural environment and conditions needed to give it the best chance of thriving in your home. The following are considered by many to be the five easiest genera (groups) of orchids to grow as houseplants. Table 1 summarizes their cultural requirements.
Phalaenopsis (group). Commonly known as 'moth orchids' the name Phalaenopsis is derived from the Greek words phalaina, moth; and opsis, appearance. Phalaenopsis orchids are very popular because of their easy care and large, long-lasting blooms. They are an ideal orchid for beginners and perform quite well under the same conditions as African violets.
Cattleya (group). Often called the queen of orchids, cattleya flowers are large and colorful. At one time they were very popular in arrangements and for corsages. Unfortunately, their flowers (which often are fragrant) typically do not last as long as other orchid types. However, their flamboyant appearance makes them a favorite among orchid enthusiasts. Cattleya has been crossed with other genera to produce exquisite hybrids that retain its growth requirements.
Paphiopedilum (group). Easily grown as houseplants, "paphs" are commonly known as the "slipper orchid" due to the slipper shape of their bloom's lower pouch. Rather than growing from a pseudobulb, these mostly terrestrial, sympodial plants instead form fans of six or more leaves. Depending on the species, the flowers are borne either singularly or in multiples.
Dendrobium (group). With more than 1000 species, dendrobium is a very large group of orchids that boast many pastel-toned blooms. Cultural requirements of dendrobium depend upon species. Dendrobium bigibbum var. compactum is a species with phalaenopsis-like flowers that is very popular in commerce and among hobbyists. Flowering usually occurs from spring to mid-summer; as is the case with phalaenopsis, blooms are very long-lasting.
Cymbidium (group). Cymbidium orchids are commonly referred to as "boat orchids" because of the shape of their lip. Flower spikes can last from one to three months with a natural blooming season during the winter. Cymbidium root systems tend to grow down rather than branch out. Most are terrestrial in their native habitat and are semi-dormant over winter, so they can take dry and cool temperatures at this time.
|Orchid||Light (f.c.)||Temperature (°F)||Water||Comments|
|When almost but not totally dry||No direct sun. Do not allow to dry out totally|
|Allow to dry between waterings||Healthy leaves should be medium green color|
|When starting to dry, but not dry||Terrestrial type. Needs porous potting medium|
|Allow to dry after growth period ends||<50° F may result in leaf drop|
|Heavy during growth period||Heavy feeders. Needs cool nights to flower|
Light intensityIn their natural habitat, most orchids receive filtered light under the protection of the forest canopy. However, orchids grown indoors need to receive quite a lot of indirect sunlight to thrive and produce blooms. The best growth activity occurs when the orchid receives 10-16 hours of indirect light. Just be sure to protect them from direct sun as they can easily get sunburned.
Growing mediumTo provide the proper environment for epiphytic orchids in our homes, most are planted in an extremely well-drained growing medium (e.g., coarse fir bark) that provides the aeration needed for the unique epiphytic roots of this orchid class. Terrestrial orchids grow well in a porous, blend of potting amendments such as sand, sphagnum moss, and gravel or fine-grade fir bark.
WateringThe visible roots of orchids can indicate how much moisture they need. If the plant needs more moisture, the roots will look silvery. Severely dehydrated roots look wrinkled and tan. Conversely, dark and mushy roots are overwatered and beginning to rot. The goal is plump roots that are green after watering, turning to a silvery-green color as they dry.
Perhaps the best way to water an orchid is by drenching the root ball in room temperature water to thoroughly wet the growing media. Collected rainwater is ideal; do not use salt-softened or distilled water. Allow the plant to drain well then place the pot in its original location. Never allow orchid roots to sit in water.
Relative humidityAlthough orchids do not like "wet feet", they do appreciate humidity levels in the 50 to 80 percent range. Consider placing orchids on a humidity tray (water-filled tray or saucer filled with gravel or pebbles to hold pots above water level) to help increase the humidity around the plants.
- Orchids love long periods of indirect light. The best growth activity occurs when the orchid receives 10-16 hours of indirect light. A good test to see if the location in question is adequately lit for your plant is to hold your hand up and check the shadow. If the shadow is blurred, light intensity is satisfactory. If the shadow is more distinct, the light level is too high, depending on species.
- Light is key when trying to achieve blooms. If you are struggling to obtain flower spikes, you might want to try to increase the length of indirect light your plant receives during the day. This does not mean that you need to increase light intensity, but rather the amount of time your plant receives light.
- Several aerial roots outside of the pot are a good sign that an orchid is actively growing. Do not trim air roots back unless they are dead. Trimming roots can cause stunt growth.
- When repotting orchids, use clear containers with adequate drainage to allow you to periodically check root health.
- Many orchid types produce spikes as a flower structure. They exist if the plant is in its reproductive life cycle. Once the plant has finished flowering, the flower spike dies. New flower spikes will produce flowers in the future. Therefore, spike trimming is necessary after the flower dies. If the spike is still green, it means that the plant potentially has the energy to push out a new flowering spike from the current spike. It speeds up the process of re-blooming to simply cut the spike back one inch above the highest node, or bump, on the spike. Brown, unhealthy spikes should be cut all the back to the base of the plant.
- Many orchids have a reproductive (flowering) cycle and a vegetative (non-flowering) cycle. Orchids can stay vegetative (non-flowering) for years if they do not receive the right environmental signals to flower.
- Some orchids such as phalaenopsis orchids need a period of cool night temperatures for 4-5 weeks before initiating flower spikes. Temperatures near 65° F at night are a good place to start for home growers. This can be as simple as placing the orchid near a north or east-facing window in winter months.
- Do not get discouraged, orchids can remain non-flowering/vegetative for 6-9 months before producing a new bloom. Patience is an important virtue for success with orchids.
Adapted from an article published by the National Garden Bureau.