^ Zhang, Guo-Qiang; Liu, Ke-Wei; Li, Zhen; Lohaus, Rolf; Hsiao, Yu-Yun; Niu, Shan-Ce; Wang, Jie-Yu; Lin, Yao-Cheng; Xu, Qing; Chen, Li-Jun; Yoshida, Kouki; Fujiwara, Sumire; Wang, Zhi-Wen; Zhang, Yong-Qiang; Mitsuda, Nobutaka; Wang, Meina; Liu, Guo-Hui; Pecoraro, Lorenzo; Huang, Hui-Xia; Xiao, Xin-Ju; Lin, Min; Wu, Xin-Yi; Wu, Wan-Lin; Chen, You-Yi; Chang, Song-Bin; Sakamoto, Shingo; Ohme-Takagi, Masaru; Yagi, Masafumi; Zeng, Si-Jin; et al. (2017). "The Apostasia genome and the evolution of orchids" (PDF). Nature. 549 (7672): 379–383. doi:10.1038/nature23897. PMID 28902843.
Here again, the type of potting mixture will be a major factor in determining how often you should water your orchid. You should also pay attention to the condition of the potting mixture, as aged growing medium that has broken down into finer particles will hold more water and take longer to drain than fresh medium, thus requiring less frequent watering.

The term "botanical orchid" loosely denotes those small-flowered, tropical orchids belonging to several genera that do not fit into the "florist" orchid category. A few of these genera contain enormous numbers of species. Some, such as Pleurothallis and Bulbophyllum, contain approximately 1700 and 2000 species, respectively, and are often extremely vegetatively diverse. The primary use of the term is among orchid hobbyists wishing to describe unusual species they grow, though it is also used to distinguish naturally occurring orchid species from horticulturally created hybrids.
The potting mixture, or growing medium, for a phalaenopsis orchid should be good at both absorbing water and providing airflow to the roots of the plant. Therefore, consider using media such as tree bark, coconut coir, clay pellets, perlite, pumice pebbles, and sphagnum moss, either on their own or blended together. If you live in a humid climate, choose a courser potting mixture that dries quickly and provides the best drainage. On the other hand, those who live in a dry climate should use a finer medium that will dry more slowly and hold more moisture. 

The Epidendroideae subfamily is the most widespread subfamily. It represents more than eighty percent of orchid species, and includes over 10,000 types of orchids. Although members of the Epidendroideae subfamily are present in temperate regions, they are most prevalent in the tropics of the Eastern and Western hemispheres. There orchids typically have single anthers with sub-erect structures.
The medial petal, called the labellum or lip (6), which is always modified and enlarged, is actually the upper medial petal; however, as the flower develops, the inferior ovary (7) or the pedicel usually rotates 180°, so that the labellum arrives at the lower part of the flower, thus becoming suitable to form a platform for pollinators. This characteristic, called resupination, occurs primitively in the family and is considered apomorphic, a derived characteristic all Orchidaceae share. The torsion of the ovary is very evident from the longitudinal section shown (below right). Some orchids have secondarily lost this resupination, e.g. Epidendrum secundum.
Another type of orchid you can grow at home is what I call the “Thai restaurant orchids.” These types of orchids are Dendrobium hybrids and can be found at Thai restaurants that decorate their tables with freshly-cut flowers. They come in many colors (white, green, purple, pink, yellow and more) and require a fairly warm environment. In fact, they could loose their leaves in the winter when the ambient temperature drops below 60°F (15°C) or so. But the “Thai restaurant orchid” is really just one small group of hybrids within the Dendrobium genus. Dendrobium is actually one of the largest orchid genera.

The orchid family is an incredibly large and diverse plant family, with more than 25,000 different species and more than 150,000 registered hybrids. The variation within a single species can be significant, let alone across the entire family. But with a little practice, knowledge, and observation, almost anyone can identify the most common types of orchids. Identifying one orchid from the next will be helpful in understanding what conditions they prefer and how to grow and flower them well. Happy growing!

Make sure the pot has drainage holes. You can't properly water an orchid unless it has holes through which the water can drain. Water sitting in the pot will cause the roots to rot, so it needs to be able to drain through the bottom. If you bought an orchid that came in an ornamental pot without holes, repot the orchid in one with adequate holes in the bottom. Use an orchid potting mix instead of regular potting soil.
Below are orchid species listed alphabetically, you can go from species to species by scrolling to the top or bottom of any page to find another alphabet bar such as this one below. All names are listed alphabetically including synonyms, so if you see your plant name without a link, there will be a reference there to procede to the name that is on this list with a link to the picture as well as cultural information for your species.
Water your orchid early in the morning. This insures complete water evaporation on the foliage as well as the crown by nightfall. If your home is very warm or has low humidity you will most likely need to water more often. The best place to water your plant is in the kitchen sink. Use lukewarm water (do not use salt softened or distilled water) and water your plant for about 15 seconds and be sure to thoroughly wet the media. Then allow the plant to drain for about 15 minutes. It may appear dry but it has had enough water. After the plants are watered, they should be placed so that the pots do not stand in water. Some people like to place the pots on "humidity trays" or in trays or saucers of gravel or pebbles and water. The pot is placed on the pebbles above the water line. This helps to insure that the base of the pot is not immersed in water, increases humidity for the plant, and provides some air circulation under the pot.
About 30,000 species of orchids come from all over the world, on every continent except Antarctica. As you can imagine, they come from a wide range of habitats and each type of orchid has different care requirements. Their incredible diversity also means you can always find another interesting orchid type to grow, which is one of the principal reasons the orchid hobby is so addictive!
The Lycaste orchid genus, similarly to its relative Anguloa, likes intermediate-to-bright light, intermediate-to-cool temperatures, and high humidity. The flowers look rather different, though; they are more-or-less triangular in shape because the sepals point outward while the petals point forward. These orchids are very fun to grow, and will thrive if you get their care right.
In orchids that produce pollinia, pollination happens as some variant of the following sequence: when the pollinator enters into the flower, it touches a viscidium, which promptly sticks to its body, generally on the head or abdomen. While leaving the flower, it pulls the pollinium out of the anther, as it is connected to the viscidium by the caudicle or stipe. The caudicle then bends and the pollinium is moved forwards and downwards. When the pollinator enters another flower of the same species, the pollinium has taken such position that it will stick to the stigma of the second flower, just below the rostellum, pollinating it. The possessors of orchids may be able to reproduce the process with a pencil, small paintbrush, or other similar device.

Using the molecular clock method, it was possible to determine the age of the major branches of the orchid family. This also confirmed that the subfamily Vanilloideae is a branch at the basal dichotomy of the monandrous orchids, and must have evolved very early in the evolution of the family. Since this subfamily occurs worldwide in tropical and subtropical regions, from tropical America to tropical Asia, New Guinea and West Africa, and the continents began to split about 100 million years ago, significant biotic exchange must have occurred after this split (since the age of Vanilla is estimated at 60 to 70 million years).

Also called the Lady’s Slipper orchid, this type of flower is easy to grow and is great for the beginner flower-grower. They come in a wide variety of colors, including cheery colors such as pink, white, and yellow, as well as more somber colors such as brown, burgundy, and near-black tones. In addition, many of the varieties include petals that have bristly hairs, freckles, and even stripes, with an added bonus of specks on some of the varieties’ leaves.

Orchids are some of the most beautiful flowers in the world, but they’re also one of the most finicky flowers. as in they require very specific and attentive care. Orchids needs the right type of soil, the right amount of sun, and just the perfect amount of water. Today we’ll show you how to water orchids correctly, how MUCH water to give them, and WHEN to water them. Watering orchids can seem complicated at first since they’re so high maintenance, but these steps will make it super easy to understand and you’ll have beautiful, thriving orchids in no time!
The sizes of the plant and its pot are also major factors to take into account in determining watering frequency. A smaller pot holding less potting mixture dries out more quickly than a larger pot holding more potting mixture. Meanwhile, a smaller plant takes up water less rapidly than a larger plant. Careful observation is, once again, the best way to know how to water your phalaenopsis orchid.
Orchids are an incredibly unique and fascinating group of plants. Many people can identify a Phalaenopsis (moth orchid) or Cattleya (the old corsage orchids), but the question often is asked, “What makes an orchid an orchid?” Orchids have some morphological (physical) traits that make them stand out from other plant families. In orchids, many of their floral parts come in groups of three. There are three sepals, which are the outer petals; these are what you see when you look at an unopened bud. There are also three petals, but in orchids one of the petals has been specialized into a labellum, or lip. This is usually the bottommost petal, and it helps to attract the pollinator to the reproductive organ. In orchids the reproductive organ, known as the column, combines both the male and female parts in one structure.
Epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis, called a velamen, has the function of absorbing humidity. It is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes.

Check your water. For a long time, serious growers insisted that orchids could only be watered with rainwater. Nowadays, most people just use tap water, and this is fine. However, be aware that treated water may have higher salt content, and some water is high in calcium. If you see deposits forming on your plants, you should seek out a new water source.

This is not a type of orchid you’ll want to place on your windowsill, because the stems grow up to four feet high. Phaius orchids have large, strappy leaves, and they usually produce petals that are yellow, purple, or white. Also known as the Nun’s Cap orchid, it is a winter bloomer and makes a great addition to anyone’s garden, regardless of what else is planted there.
Some orchids have water-storing organs, and some do not. If you have a type of orchid that has the ability to store water, such as cattleyas or oncidiums, you should allow the orchid to completely dry out before watering. If you have a type of orchid that does not have water-storing organs, such as phalaenopsis or paphiopedilums, you should water the orchid before it is entirely dry.
Many neotropical orchids are pollinated by male orchid bees, which visit the flowers to gather volatile chemicals they require to synthesize pheromonal attractants. Males of such species as Euglossa imperialis or Eulaema meriana have been observed to leave their territories periodically to forage for aromatic compounds, such as cineole, to synthesize pheromone for attracting and mating with females.[10][11] Each type of orchid places the pollinia on a different body part of a different species of bee, so as to enforce proper cross-pollination.
Orchid stems are also specialized into what are called pseudobulbs. These are basically expanded stems that allow the plant to store excess water and food. The roots of epiphytic (tree-dwelling) orchids have a special outer layer of dead cells called velamen. Because orchids metabolize slowly in order to not outpace their resources, the roots also absorb slowly, meaning that they need help catching water as it passes by. The velamen cells catch and fill with water as it passes by so that the true root (the core of the root structure) has ample time to access as much water as it can. Velamen is silver-white in color, but becomes transparent when wet, so that when the root is wet it turns green as you are able to see through to the inner structures of the root that contain chlorophyll.

My favorite type of orchid is the lady slipper orchid because of their strange appearance. They are like no other types of flowers and have pouch-shaped lips. The mostly terrestrial and lithophytic slipper orchids include four genera—Paphiopedilum, Phragmipedium, Cypripedium and Selenipedium. But most Cypripedium and Selenipedium are not plants for the beginner because they can be quite difficult to grow under cultivation unless you live in temperate regions with Cypripedium growing wildly in your back yard!

The type of potting medium being used can also affect your plant's water requirements. Bark has a tendency to dry out more rapidly than sphagnum moss, for instance. It is important to remember, however, that even when the surface of your pot is dry, the root area may remain moist. Poke your finger or a regular wooden pencil an inch into the pot; if it feels moist to the touch or if the pencil looks moist, do not add additional water. The potting medium should always be damp, but not soggy—neither should it be allowed to get extremely dry.
Asking me what types of orchids there are is like asking me what types of people there are. Well, there are tall and short people, smart people and not-so-smart people, introverts and extroverts, people with different skin colors, and people from different parts of the world. Likewise, you will find many different types of orchids—different colors, species and hybrids, miniature and standard-sized, all different genera from different parts of the world. So I will narrow the question a bit, and look at it in terms of the orchids you will likely to buy and grow.

The Cypripedioideae subfamily is known for its lady slipper orchids, which are named after their slipper-shaped pouches that trap insects and help the flowers get pollinated. There are 5 genera in this subfamily: Cypripedium, Mexipedium, Paphiopedilum, Phragmipedium, and Selenipedium. Cypripedioideae orchids have two lateral, fertile anthers, which is unusual in most other orchids.