There are over 25,000 species of orchids in the world, and more than 105,000 manmade hybrids as well. The number continues to increase as new species are discovered and new hybrids are developed. Orchidaceae is the largest and most diverse family of flowering plants (Angiospermae).
Botanists consider orchids to be among the most advanced floral evolution known, because of their symbiosis with mycorrhizal fungi (in root system) and their interactions with pollinators. Some orchids are shaped so only one species of insect can reach the pollen, while others are pollinated by birds. Orchids are found worldwide. Some are terrestrial, many are epiphytes (grows on another plant) and a few are lithophytes (grows on rocks or stones).
Terrestrial orchids grow rooted in the soil, especially in leaf compost on the forest floor. Some species are rhizomatous, forming corms or tubers to store food and water. Terrestrials are mostly found in cool climates.
These plants use trees for support and do not require soil. They normally grow in warm regions. They have modified aerial roots covered with a spongy, water-absorbent surface called velamen. These silver-gray or white roots can be ten feet long, to help them absorb more moisture. In species that have no leaves, the roots also contain chlorophyll.
A few species are lithophytes, growing in and on rocks. They feed off litter, moss, nutrients in rainwater, and sometimes even their own dead tissue.
Best Houseplant Orchids
Since there are so many species, and they grow under very different conditions, you're best to start with orchids ideal for houseplants. Two genera are readily adaptable to being grown as houseplants, paphiopedilum and phalaenopsis.
Paphiopedilum is a genus containing about 77 species native to South China, India, Southeast Asia, and the Pacific Islands. The name is derived from the Greek city Paphos and the word pedilon that means slipper. This type is often called Slipper or Lady's Slipper orchids because of the pouch-shaped labellum of the flower. The pouch traps insects so they're forced to climb up past the staminode to collect and/or deposit pollen.
Phalaenopsis (moth orchid) is a genus of containing about 60 species. The name comes from the Greek words phalaina (moth) and opsis (like). They are often called Moth Orchids, because a cluster of blossoms on a flower spike resemble a group of moths in flight.
- A few phalaenopsis are lithophytes.
- Most phalaenopsis are epiphytic shade plants.
- A healthy plant produces one or two thick, fleshy leaves each year, with the oldest leaves dropping off.
- Phalaenopsis do not produce pseudobulbs (storage organ).
- The blooms can last as long as three months.
Phalaenopsis also have a unique photosynthetic mechanism. In most plants, the flower petals wilt and disintegrate after the plant is pollinated. Phalaenopsis petals turn green, become fleshier, and photosynthesize.
How to Grow Orchids Indoors
The key to growing orchids successfully is to reproduce the conditions of their natural habitats. Hobby growers often end up building greenhouses for their orchid collection!
Domestic orchids are grown in soilless mediums. Sometimes they're grown clinging to bits of wood or wire supports.
- Nutrients are supplied with a range of liquid fertilizers.
- Fertilizers are applied in dilute solutions.
- Light exposure, temperature, and humidity levels are carefully controlled.
Temperature control should be regulated since flower buds can fall away if the temperature changes are erratic. The temperature for orchids can vary according to the species. For example, phalaenopsis must have temperatures during the day between 65° F to 85° F with night temperature above 60° F. Some orchids may require 55° F at night for a couple of weeks to stimulate flower spikes.
On an average, most orchids require high humidity. Depending on the species, that can fall between 50% to 80%. If growing orchids in a greenhouse, you want the leaves to be dry by nightfall, which requires circulating air.
Humidity for Orchids in Home
You can provide the necessary humidity for home orchids by setting the orchid pot in a humidity tray. This tray holds gravel submerged half way in water. You will then place the orchid pot on top of the gravel. This guards the root system from the water, while provide moisture (humidity) for the orchid.
Most people tend to over water orchids. You can tell when your plant needs way when the soil is dry. You can test with your fingertip. If the top layer of soil is dry, you can safely water your orchid. Orchids grown in homes with low humidity will require more frequent watering.
- Always water in the morning to allow time for your orchid to absorb the moisture.
- Water with lukewarm water.
- Never use water that is softened with salt systems or distilled water. Filtered water is preferred over chlorine and chemically treated water.
- Place plant in sink and allow to soak up water for 15-20 seconds.
- Allow plant to drain for 20 minutes in a tray of gravel to allow thorough drainage.
How to Fertilize Orchids
You'll need to feed your orchid a 20-20-20 fertilizer. This balanced fertilizer should contain all of the necessary trace elements your plant requires.
- Apply fertilizer on a regular basis by diluting per manufacturer's directions and apply once a month.
- Water prior to fertilizing for less chance of burning the roots.
- Don't overfertilize your orchid.
- If you prefer more frequent fertilizing, you can dilute one-half to one-fourth the regular dilution ratio.
Some fertilizers are intended to be sprayed onto the entire plant. Check manufacturer's instructions.
Repotting Your Orchid
You will need to report your orchid when it outgrows its pot or if you notice the roots are beginning to die. The latter may not require a new pot, depending if the roots are root bound or simply need for the growing medium to be replaced.
Best Orchid Growing Medium
The best growing medium for your orchid is either a bark and moss mix since it drains well, a clay pebble medium that retains water, or a peat mix that retains water. Some orchids have a recommended medium for best growing results.
Light Requirement for Growing Orchids
The best place to grow orchids is a bright room with east-facing windows or a south-facing windows. Both directions will allow your orchid to receive an abundance of sunlight.
- Avoid direct sunlight since the orchid will easily sunburn.
- You should avoid the west windows since afternoon sun can be too intense and hot for orchids.
- The north direction won't provide enough light for your orchids to survive.
- You can diffuse the sunlight with a sheer curtain if needed.
Pruning Your Orchid
Orchids don't require a lot of pruning. You need to deadhead any faded blooms. You will need to prune brown and yellow spikes all the way to the base of the plant. Green healthy spikes can be trimmed by cutting just one inch above the node located underneath the flower bloom.
Common Growing Problems for Orchids
There are a few common problems that first-time growers have with orchids. Most have easy solutions.
If the orchid leaves begin to shrivel up, wrinkle or take on a rather leathery appearance, you need to determine the cause. There are two possible causes, under or over watering.
Over Watered Orchids
If the roots have a plump appearance and are green and/or white, then chances are you've over watered your orchid. Allow the plant to dry out some and the leaves should revive.
If the roots are dry, you haven't watered your orchid enough. You need to give the plant time to recover, so place it in a spot with higher humidity to allow it to recover. You may need to repot or change out the medium.
Orchids Don't Bloom or Rebloom
This problem is easily solved by providing more sunlight for the orchid. You can gauge the amount of sun your orchid is receiving by the color of the leaves. You want a light green that borders on the side of slightly yellow-green tinge for a sign that your plant has received enough sunlight to bloom. You may need to stimulate reblooming by placing the orchid in cooler temperatures of around 55° F but above 35° F for a few days.
How to Grow Terrestrial Orchids
You can grow terrestrial orchids outdoors either directly in the ground or in pots. Depending on your local environment, you can check the requirements for the orchid species you wish to grow to see if it is compatible with your region.
- Temperatures should be above 55° F, and in some cases 65° F, before planting outside.
- Plant terrestrial orchids where they receive morning and late afternoon sun, preferably not direct sun.
- Potted orchids should never be set on the ground to avoid insects, like ants.
- Water every two weeks and avoid getting water on the plant by directing the water on the ground.
- Plant in a shady spot or an area that only receives morning or afternoon sun.
- Fertilize once every two months if planted in fertile soil.
Growing Orchids in a Hobby Greenhouse
Serious orchid growers invest in a hobby greenhouse. This is a big expense in structure and equipment and is usually undertaken by avid orchid lovers.
An ideal setting for climate control to grow orchids is a greenhouse. Just as planting in a garden setting, your greenhouse should be a north to south direction. This allows the sun to provide the best possible lighting. However, you can always provide light and proper shade if you don't have the ideal greenhouse location.
You will need a good heating system for climates with low temperatures, such as 45° F and below. Some choices include steam heat, forced air and radiant heat. You may need a cooling system for climates with high temperatures.
Humidity Control and Greenhouse Equipment
You will need to invest in an automatic humidifier along with a good air circulator and ventilation systems. This can include roof vents, side vents and fans. You may also need shading options.
Other greenhouse equipment and systems may include:
- Exhaust fans
- Irrigation system on timers
- Fogger systems for misting
- Fans for air circulation
Scientific Classification of Orchids
All species rely on mycorrhizal associations with various basidiomyceteous fungi to reproduce. Some species lack chlorophyll and depend entirely on these fungi for their nutrients. The classification of orchids includes:
- Kingdom: Plantae
- Division: Magnoliophyta
- Class: Liliopsida
- Order: Asparagales
- Family: Orchidaceae
- Subfamilies: Five subfamilies include Apostasioideae, Cypripedioideae, Epidendroideae, Orchidoideae, and Vanilloideae
- Genus: More than 800 genera
Learning to Grow Orchids
You can grow orchids indoors, outdoors or in a greenhouse. Each has specific growing advantages. Whatever way you choose to grow orchids, you're sure to enjoy the elegant beauty these tropical flowers bring to any setting.