Opened on February 26, 2021. Last updated by The POOG on March 02, 2021.
The orchid family Orchidaceae (for the taxonomy see Classification for Kingdom Plantae Down to Family Orchidaceae) is the second largest family of flowering plants, with about 880 genera and some 26,000 species distributed nearly worldwide. The number of hybrid varieties created adds significantly to this total. They are found from sea level to above tree lines on mountains. Their culture ranges from easy as is the case for the two genera that I grow listed below, to very difficult requiring expertise, such as genus Masdevallia. Propagation by seed cannot be done by the average person as it requires a lab to create special growing confitioms.
The orchid family covers a very wide range of growing conditions that are particular to each species. Many if not most are epiphytic, meaning that they absorb water and nutrients through exposed roots. They need to have air around their roots. If they are planted in soil or any material that is dense and keeps the roots wet or immersed in water, the roots will rot and the plant will die.
The traditional planting material used by orchid growers is chopped pine bark. Chopped coconut husk is now more commonly used since it is more readily available in the retail market. Coconut coir is too finely ground to drain well and allow air circulation around the roots. Consequently, it should not be used for orchids.
I know of at least one commercial grower that uses sphagnum moss. It offers the grower advantages due to its water retention, giving a longer shelf-life for retailers who are not likely to water the plant. They are usually marketed with an instruction to water with one or two ice cubes a week. The reason for this is that it is a very measured amount of water that the plant will receive without saturating the moss and killing the roots. When I buy such a commercial plant I re-pot it within a day or two in coconut husk.
Watering and Fertilizing
Watering should be done when the surface potting material is dry to touch. I place the orchids in a bathtub and give them a shower. For one or two plants, soak them in the kitchen sink. Submerging them for 5 minutes will not hurt them and will allow the potting material to absorb a maximum of water. Drain the pot afterwards until it stops dripping. The moist, coarse potting material will allow air around the roots creating a micro-climate of high humidity. I water every week to 10 days depending on the relative humidity in the house. Lower in winter or dry areas means water more frequently. After I have watered my plants and allowed them to drain, I apply a weak fertilizer solution of a composition recommended for orchids (e.g. 15-30-15). There is a saying among orchid enthusiasts: “water weakly weekly.”
Orchids generally do not like direct sunlight which will burn and kill most species. I use a north-facing window for a lot of my plants and they thrive and bloom for me every year. East windows are good. South and west windows are to be avoided unless a shade cloth is used.
I live in a hardiness zone rated 6b having moved from 5a. I. have an outdoor growing bench covered with a 50% shade cloth which I find insufficient. I’d recommend a 75% cloth if the bench is in sunlight at all. I move my plants outside when the danger of frost is past and the night temperature won’t go below 4 or 5 degrees Celsius in the 2-week forecast (that’s cool I know but works for me). In the fall I bring them inside when the forecast night temperature is going below 4 or 5 degrees Celsius. Frost will kill them.
I find with the outdoor plants, rain is usually sufficient in my area. I’ll water the bench with a hose if we get into a hot, dry period.
A Word on Pests and Diseases
Do not place plants on the ground, even in shade. Slugs and snails will find them I discovered. In our move, I set my plants under some trees for three weeks until I could get the bench set up. It took a month to completely eradicate these pests when I discovered the problem and. I had to throw out more than half my collection.
I fought mealy bugs for three years unsuccessfully. I tried everything including cygon 2e and sevin. In the end, I simply threw out any infested plant that I had not been able to clean up. In the process, I discovered that new plants that I was buying at the supermarket may have been the source of continued infection. Now, if I buy a plant, I isolate it for at least 2 months to see if I got more than what I paid for.
Most diseases are either bacterial, fungal, or viral infections. There are several good sources describing, along with pictures, how to identify and treat the various infections.
Most plants need a change in growing conditions to trigger the flowering/seed production cycle. Usually, some form of stress is a trigger. When the plant feels threatened, it knows it is time to create seed for the next generation. Reducing water is a trigger for some. Shortening daylight period will trigger others. Commercial greenhouse growers use controlled lighting a lot.
A cold period works well for me since, when I bring them indoors, the nights are chilly. Within 2 moths I will see the first new flower spikes forming. To the novice grower it can be confusing when new aerial roots are forming. These have a characteristic tip different from a flower spike in Phalaenopsis orchids.
The flower spike emerge laterally at an angle from a leaf axil and has to be trained by clipping to a stake to get a vertical orientation. I recently bought a miniature Phalaenopsis with 4 spikes, but be happy if you get two. When you buy a plant in bloom you are looking at the blossom. But also make sure the leaves and exposed roots all look healthy too.
If there is one rule to distill this down to, it is practice benign neglect.
The Phalaenopsis (moth orchid, or ‘Phal’ for short) genus, (genus Phalaenopsis), consists of about 60 species native to southeastern Asia and part of Australia. It is the most popular orchid genus for the commercial market, being very easy to grow in the home environment. It has been extensively hybridized and some species are fragrant.
With normal care, the flower spike will continue to produce blossoms off of it for as long as 4 months. Pollination of orchids by hand is difficult and small-flowered varieties require a magnifying device and a steady hands. Although I have successfully pollinated a Catleya species orchid resulting in a seed pod, I did not have access to laboratory conditions to germinate the seeds.
Blossoms in my collection range in width from 4 cm (about 1.5 inch) to more than 11 cm (about 4.5 inches). When the blossoming is finished, the spike may be cut off at its base. A new spike will be grown the next year from a different leaf axil. Alternately, you can leave the spike. If it turns brown, cut it off. If it stays green, it will likely send out new side branches the next year, giving a fuller blossom display.
Phals grow vertically with the newest leaf formic at the base of the current top leaf. This tender new leaf is most appetizing to pests that will attack and destroy it. If the terminal leaf is destroyed when developing, it is unlikely that the plant will be able to grow any more leaves. Throw the plant out. It cannot be propagated from cuttings or by division to my knowledge.
Pests and Diseases
There are a few sites that describe Phal pests and diseases specifically, in addition to the general sites above. If you have only one or two plants with a problem, isolate them and treat them separately from the rest of your collection. For common varieties that you can pick up in the supermarket for $10, don’t spend too many resources on a diseased plant. Throw the diseased plant out and start with a new one. The same goes for plants that are late in their life and their structure or appearance is no longer visually appealing.
Oncidiums form a genus of some 300 species of tropical and subtropical American orchids and are sometimes given popular names such as bee orchid, tiger orchid, and dancing lady.
The plants vary greatly in size and shape, and most species are epiphytic. The plants have pseudobulbs or bulbous-based stems used to store water for dry seasons. The flowers are often yellow or brown and are commonly borne on spikes or in long spray. Blossoms range in width from 6 mm (about 0.25 inch) to more than 10 cm (about 4 inches), depending on the species.
Below is an Oncidium that I grow. It is morning fragrant because in its native environment it has to attract a pollinator active in the early part of the day. The main flower spike has dozens of blossoms a centimetre across. The bloom last 2-3 weeks. This was purchased in a supermarket by making an offer of a couple of dollars to the produce manager since since at that time, it was finished flowering and unsalable. Make sure the plant itself is healthy. Such plants are never identifies by species or variety so these remain unknown.
I grow my Oncidiums with the same culture and care that I use for Phals.
I have grown plants in the Catleya and Cymbidium genera. Cymbidiums are difficult to get to flower but are rewarding with a tall flower spike of large blossoms up to 3 feet or more. They are field grown in nurseries in California. Apart from the difficulty with flowering, I found, due to their culture, pest problems came with them. The other point is that they are a large plant. This works as a single plant in a living-room but limits the size of your collection due to space constraints.
Catleyas, sometimes called the corsage orchid, are among the showiest. Many are fragrant. They require a more careful culture and growing conditions.
- Petruzzello M. List of plants in the family Orchidaceae. Britannica.
- Moth orchid. Britannica.
- Oncidium. Britannica.
- Orchid Pests and Diseases – Orchid Diseases. SAOS.
- Orchid Pests and Diseases. AOS.
- Ryczkowski A. Phalaenopsis Orchid Disease. SFGate.
- Moth Orchid: Pests and Diseases. PhalaenopsisCare.
- Common Phalaenopsis Orchid Diseases (Part 1) November 28, 2012.
- Common Phalaenopsis Orchid Diseases (Part 2) November 30, 2012.
- Blackstone VL. Wilted Leaves on the Phalaenopsis. SFGate.
- Blackstone VL. Pseudomonas Disease in Phalaenopsis. SFGate.
- Bottom S. Orchid Pests and Diseases – Diagnosis, Treatment and Prevention.