Avoid overwatering which leads to the demise of many more orchids than underwatering. Constant wetness will cause the roots to rot, which leaves the plant without a means for taking up nourishment which then causes the leaves to droop and will eventually kill the plant. The classic advice is to water the day before the plant dries out. If you have to let the plant go dry to figure out what a dry plant weighs, it will not kill the plant and will make you a better grower. Another measure is to use the pencil trick (the point of a sharpened pencil, when inserted into the medium, will darken with moisture if the plant has enough water). And, there's always the old standby - put your finger in the mix. If it feels wet, it is wet. If you aren't sure whether it is time to water, wait one more day.
This site is compiled from photos collected from growers or photo collectors around the world and I rely on them to try to be sure of their identification. As we all know, however, many plants are mislabeled and growers and collectors can't know all species in every genera, so please be advised that to the best of our knowledge the following ID's are correct. I have hundreds of references, thanks to you all, but often many species are not well represented. I try to the best of my capabilities to be correct but as the adage goes, "To err is human". Many species herewith have been scrutinized by taxonomic experts and will be correct, but this may not be true of all the species described. If you have any questions as to the veracity of any species described in this encyclopedia please e-mail me, Jay Pfahl, at jfal@sprynet.com and we will work at correcting the mistake. As to the text it is compiled by culling notes from hundreds of books and publications [See Bibliography and source books] but it too can be wrong in part due to my mistake or in the often conflicting reports on various orchids.
Orchids of all types have also often been sought by collectors of both species and hybrids. Many hundreds of societies and clubs worldwide have been established. These can be small, local clubs, or larger, national organisations such as the American Orchid Society. Both serve to encourage cultivation and collection of orchids, but some go further by concentrating on conservation or research.
The variety of orchid plant types is amazing. Some bloom for weeks at a time, while others keep their flowers an amazing four months or more. Always check the tag that comes with the plant to determine the optimum temperature for your orchid. Choose one that fits in with your normal indoor environment, rather than trying to change your environment to fit the orchid.

Did you know there are more than 20,000 types of orchids in the world? That’s more than four times the number of mammal species! While most are found in tropical rainforests and grasslands in far off places, a fair amount are also native to the United States. A favorite in homes worldwide, the “Orchidaceae” family features blooms that are vibrant, tropical and fragrant.

With ageing, the pseudobulb sheds its leaves and becomes dormant. At this stage, it is often called a backbulb. Backbulbs still hold nutrition for the plant, but then a pseudobulb usually takes over, exploiting the last reserves accumulated in the backbulb, which eventually dies off, too. A pseudobulb typically lives for about five years. Orchids without noticeable pseudobulbs are also said to have growths, an individual component of a sympodial plant.

A majority of orchids are perennial epiphytes, which grow anchored to trees or shrubs in the tropics and subtropics. Species such as Angraecum sororium are lithophytes,[24] growing on rocks or very rocky soil. Other orchids (including the majority of temperate Orchidaceae) are terrestrial and can be found in habitat areas such as grasslands or forest.
Catasetum orchids, along with the other members of the Catasetum alliance, have big, thick pseudobulbs with an attractive fan of thin leaves along their length. The flowers can be very showy, but are unisexual, so that male and female flowers look different. Lighting affects which kind appears. They need a dry rest after flowering when the leaves drop.
A study in the scientific journal Nature has hypothesised that the origin of orchids goes back much longer than originally expected.[14] An extinct species of stingless bee, Proplebeia dominicana, was found trapped in Miocene amber from about 15-20 million years ago. The bee was carrying pollen of a previously unknown orchid taxon, Meliorchis caribea, on its wings. This find is the first evidence of fossilised orchids to date[14] and shows insects were active pollinators of orchids then. This extinct orchid, M. caribea, has been placed within the extant tribe Cranichideae, subtribe Goodyerinae (subfamily Orchidoideae). An even older orchid species, Succinanthera baltica, was described from the Eocene Baltic amber by Poinar & Rasmussen (2017).[15]
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.
Dendrobium species live as epiphytes and lithophytes in New Guinea, Southern China, Thailand, Japan, Australia, New Zealand, Tahiti and more. As a result, it’s hard to generalize how to care for these types of orchids. Some of them require cool nights of 50 to 59°F (10 to 15°C) while some of them require warm temperatures in the 80s°F (27°C). That’s why it’s so important to understand their natural environment so that you can make them happy. Learn more about Dendrobium orchids.
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.
Run the orchid under water. The easiest way to water an orchid is to hold it under a faucet and run it under room temperature water. If you have an attachment that allows you to diffuse the water, rather than just running it in one strong stream, that's better for the orchid. Water the orchid this way for a full minute, allowing the water to seep through the pot and come out the holes in the bottom.[3]
Always water early in the day so that your orchids dry out by nighttime. The proper frequency of watering will depend on the climatic conditions where you live. In general, water once a week during the winter and twice a week when the weather turns warm and dry. The size of your orchid container also helps determine how often you need to water, regardless of climate conditions. Typically, a 6-inch pot needs water every 7 days and a 4-inch pot needs water every 5 to 6 days.
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.
Phragmipedium: Phragmipedium orchids are interesting in that they are one of the few orchids to produce vibrant flowers in an intermediate environment. You see, normally it is the extremes of climate that produce the most interesting colors. But this type of orchid is great for you if you have a temperate and mild climate but desire bright blossoms. 

If your Catasetum orchid leaves begin to yellow and drop off, do not despair; this deciduous orchid loses its leaves naturally during winter dormancy. There is much variation in appearance between Catasetum species, but one feature they all have in common is the trait of producing male or female flowers, which bear little resemblance to each other. The male flowers have an anatomical trigger that forcefully ejects pollen onto visiting bees.
Cymbidium carry tall stems with many flowers that have a more typical orchid shape. They are easily identified by their grassy leaves, and they readily form large clumps. Most common are the cool-flowering types, which need to experience a cooler winter (nights in the 40s for some time in the fall) in order to initiate flowering. Once the flowers open, they can last for up to two months or more, especially in a cool environment. These are very showy and rewarding plants, and a plant in a six-inch pot can carry three stems with 15 or more flowers each, depending on the type.