Orchids are known for their vibrant, exotic colors and diverse variety, with over 30,000 species and 200,000 hybrids. Once only available to the rich, orchids can now be cultivated almost anywhere and have become popular houseplants. Most orchids found in nature are epiphytes, which are plants that grow anchored to other plants. Although they can be found anywhere except Antarctica, the vast majority are native to the tropics, where they thrive in the wet, humid environment. Below is an overview of several categories of orchids.
- Epiphytes: Approximately 70% of orchids are epiphytes, and are largely confined to the tropics or subtropics. They are not parasitic, as they do not derive nutrients from the host plant.
- Terrestrial orchids: Like the name suggests, terrestrial orchids grow in the soil. Some have roots, but most grow from pseudobulbs.
- Phalaenopsis hybrids: Also called moth orchids, these orchids are suited to beginners due to their showy blooms and ease of maintenance.
- Dendrobium hybrids: This variety of orchid is one of the largest of all orchid groups, comprising nearly 2000 species. In nature, they are primarily epiphytes. Native to southeast Asia, they are found in a wide range of climates – from hot wetlands to high-altitude cold mountains. Some species are found in the deserts of Australia.
Conditions for Growing Orchids
Caring instructions differ depending on their variety. In general, orchids grow best when their environment mimics their natural habitat, which can sometimes be extrapolated based on their appearance. If the plant has leathery leaves, it is likely that it will need a high-light environment. If the leaves are soft and limp, then they are light averse and should not be placed in an overly sunny spot. If it has large pseudobulbs, which store water, then they should be watered less than those with no pseudobulbs.
Light: Orchids need a moderate amount of light. The ideal location is a lightly shaded south or east facing window. Avoid placing them in direct sunlight, which can burn the leaves. If you are having trouble finding a good location, you can use artificial lights for your orchids. Some varieties, such as cymbidiums, should be grown in the maximum amount of light. Phalaenopsis can tolerate low light and do well under grow lights placed about a foot from the plant. Occasionally rotate your plants to keep growth equal.
Soil: The potting material for orchids should be well draining and provide good air circulation. Since most orchids are epiphytes that grow on trees, they require growing mediums that mimic their natural environment, which consists of bark and moss. Common growing mediums include peat moss, fir bark, dried fern roots, perlite, and coconut fiber. You can buy an orchid potting mix or make your own using a combination of peat moss, perlite, or fir bark.
Although most gardeners grow orchids inside, orchids can be grown outside if the climate is suitable. Most orchids cannot tolerate temperatures below 50°F, with ideal nighttime temperatures being 60 – 70°F. Avoid planting them in places with total shade or direct sun, except for moth orchids, who should be given shade. Epiphyte orchids cannot be directly planted into the ground, but you can grow them in containers or raised garden beds filled with well drained orchid mix. They can also be grown in hanging baskets or mounted slabs in a greenhouse-type environment.
Water: In general, most indoor varieties should be watered once a week. Overwatering can be detrimental to their roots and cause them to become waterlogged. Orchids with large water-storing pseudobulbs have a high drought tolerance, and should be watered sparingly. To prevent overwatering, let the plant completely dry before watering again.
Orchid roots are surrounded by a tissue called velamen, which absorbs water, adheres to rough surfaces, and promotes the exchange of minerals and salts. It can indicate if orchids need watering, as dry velamen is white or silvery, while freshly watered velamen is green or mottled in color. There are several factors that affect the watering frequency, including potting mix, species, temperature, humidity and airflow. If your potting mix has a higher water retention, water your plants less. Greater airflow tends to dry them out quickly, so increase watering when necessary.
Temperature and Humidity: Dendrobium orchids prefer warm climates with a temperature above 60°F. Moth orchids prefer temperatures between 75 – 85°F, although they can adapt to 65 – 70°F. Almost all orchids do best when the humidity ranges from 40% to 70%.
There are several ways to increase humidity levels, which are especially low during the winter months. You can add ferns or other houseplants to the area. In addition, you can also use humidity trays. Fill the tray with gravel and pour water until it is half way full. You can also use a humidifier or mist your orchids at their roots. To improve air flow, set a fan next to your orchids, making sure it is facing away from them.
Fertilizer: Orchids need fertilizer as the potting mix they are planted in do not provide adequate nutrients. During the growing season, apply a weak orchid fertilizer following label instructions. Fertilize Phalaenopsis orchids twice a month or once a month after its blooms have dropped. Fertilizer should be applied only during the active growing months, which means they should not be fertilized in mid-winter, or immediately after they have been repotted.
How to Repot and Propagate Orchids
Repotting: Orchids need repotting when you notice the growing medium has been broken into smaller chunks, or white roots are growing out of the container. If you have an orchid that grows pseudobulbs, repot it after blooming and before the roots begin to grow. For other orchids, you can repot them anytime, although you should not disturb them when they are flowering.
To repot, choose a pot that is an inch or two bigger than the previous one. Remove the orchid from its pot and loosen the roots, using a clean scissor to remove dead or rotting roots. Place the orchid over the pot, and fill it with the growing medium you are using.
Propagation: It is difficult to propagate orchids from seed. The most common methods are stem cuttings or plant division. To grow from stem cuttings, choose a stem that is healthy and at least 10 inches long, with a good aerial root system attached. Cut off the stem above a node, or leaf joint. Divide the stems into smaller pieces with at least two nodes and place them in a tray of damp sphagnum moss. After a few months, you should see new root and leaf growth.
In division, the rhizomes of the orchid are separated. You should use this method if your orchid is a few years old and has finished flowering or is too large for its pot. Make sure the orchid you are propagating has many healthy pseudobulbs. Remove the orchid from its planter and loosen the roots, dividing the clumps into sections with 3 – 4 actively growing bulbs. Plant them in a growing medium and wait for the roots to develop.
Orchids can also be grown from back bulbs, which are old pseudobulbs furthest from the growing lead. Some of them have active eyes that can be treated similarly to a division. If they do not have an active eye, then plant them in small pots, making sure the eyes are resting above the potting media. Spray the bulb and leaves frequently, but don’t soak the soil. The bulbs may suddenly burst into activity within a few weeks, or can lay dormant for two years.
Finally, monopodial orchids can also be propagated through offshoots along the stem, known as a ‘keiki’. Orchids from the following varieties can be propagated through keikis: Phalaenopsis, Epidendrum, Oncidium and Dendrobium. They can be allowed to mature before being separated from the main plant. The keiki should have at least three leaves and roots that are 2 – 3 inches long. Remove the keiki and repot it using a well-draining orchid mix, fir bark, or peat moss. Mist the plant daily, keeping it away from direct sunlight. Once it becomes established, you can move it to a brighter area.