Consider your climate. The frequency with which you water orchids is affected by the level of humidity in your climate, as well as the amount of sun the orchid gets and the temperature of the air. Since these factors vary according to region and household, there's no rule for how often to water an orchid. You'll have to develop a routine catered to your specific environment.
Cool growing Colombian Orchids - Photos of Orchids in situ near Bogota' Colombia - #1 Epidendrum sp., #2 Epidendrum polystachyum",#2 Epidendrum polystachyum young plant,#3 Epidendrum excisum in flower, Epidendrum excisum Same plant,#4 Epidendrum secundum., Maxillaria sp., Pleurothallis sp.and Odontoglossum lindenii ,Odontoglossum ramulosum, Odontoglossum ramulosum flowercloseup
The vast majority of orchids grown in the home are epiphytes, meaning they live in nature by clinging to trees or even stones. The roots of these plants are highly specialized organs that differ dramatically from normal plant roots. Of course, it's hard to generalize about anything when it comes to orchids. This is the single largest group of plants in the world, so for every rule, there are 100 exceptions.
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.
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.

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.
My point is, I was always afraid to try these beautiful plants. I thought they would be to hard to grow . Thanks to the internet and great sites like this one you can’t go wrong. I am so happy I bought my first one, I am a complete addict now! Just be sure you look at the roots before you buy, not the flowers and never let the bottom of your inner pot sit on the ‘floor’ of the exterior vase, I line mine with fish tank rock. I live in AZ where humidity is nonexistent so I run a small fan for my flowers as well to help with humidity as well as air flow.
This tribe is fairly large and consists of four genera — Dendrochilum, Pholidota, Chelonistele, and Coelogyne — and over 300 species. They are native to the tropical and subtropical regions of the Old World. Coelogyne is the most popular genus. Its orchids are characterized by a three-lobed lip that is concave at the base, and a hooded or winged column.
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.
The most important thing to know about how to water phalaenopsis orchids is that you should only water the roots, making sure to leave the crown (leaves, flowers, and stem) dry.  Moisture on these parts of the plant can cause problems such as mold, fungus, and tissue rot – especially if water gets trapped in pockets such as those that form where there’s new growth. If you do get water on any part of the crown, use a paper towel to remove the moisture.
^ Thomas J. Givnish, Daniel Spalink, Mercedes Ames, Stephanie P. Lyon, Steven J. Hunter, Alejandro Zuluaga, William J.D. Iles, Mark A. Clements, Mary T.K. Arroyo, James Leebens-Mack, Lorena Endara, Ricardo Kriebel, Kurt M. Neubig, W. Mark Whitten, Norris H. Williams, and Kenneth M. Cameron. 2015. "Orchid phylogenomics and multiple drivers of their extraordinary diversification". Proceedings of the Royal Society, series B (biological sciences) 282(1814):pages??. doi:10.1098/rspb.2015.1553.[full citation needed]
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.
In the wild, Phalaenopsis are epiphytes and grow on trees in a constantly moist environment. They usually have long flower spikes and therefore look very graceful. These types of flowers have the power to add elegance to the home and brighten up a dull atmosphere, even if your boyfriend leaves his socks on the floor. Phalaenopsis are now widely grown as houseplants. Even though they usually bloom only once or twice a year, their flowers can often last for two to three months. Learn more about Phalaenopsis orchids.

Cycnoches orchids have unisexual flowers, meaning they have separate male and female flowers which look different (usually just one of the two types of orchid flowers each time it blooms). The flowers are usually make a very dramatic display. After flowering, the leaves drop off and it enters a dry rest; don't water until it starts to grow again or it will rot.
With a shape that is similar to a dancing lady, the Oncidium orchid is low-maintenance and easy to grow, and it comes in stunning colors such as bright yellow and gold. The variety called Sharry Baby has a chocolate-like scent, and although simple to grow, the Oncidium orchid does require a lot of moisture and humidity to thrive. If you notice any type of deformities in the leaves of this plant, it is likely because this requirement has not been met. They are truly beautiful bloomers.
Dendrobium is a massive genus containing more than (conservatively) 900 species. These range from cool-growing miniatures to huge specimen plants growing in hot conditions year round. The most commonly found types of Dendrobium are the phalaenopsis type (commonly known as den-phals, and named for the species most used in their breeding, which used to be known as Dendrobium phalaenopsis, but which is now known as Dendrobium bigibbum), and the nobile type (named for the species most used in their breeding, which is known as Dendrobium nobile).
So you want to grow an orchid? There are tens of thousands of orchid varieties to choose from, in almost every color of the rainbow. Some exotic versions are rarely seen outside specialty shows, while others are readily available to the novice grower. Unlike the common stereotype, many types of orchids will thrive as houseplants, and don’t need to be kept in a greenhouse. The orchid you’ll choose to grow will depend on the environment in your home, as well as the way the plant looks.
With the different orchid types, it’s important to master the watering schedule. If orchids have pseudobulbs, enlarged stem structures that store water, the orchid potting mix can dry out a little between waterings. Orchid species that are epiphytes and grow on tree branches in tropical rainforests are adapted to receiving water from daily rain, so they need more frequent watering.  
So you want to grow an orchid? There are tens of thousands of orchid varieties to choose from, in almost every color of the rainbow. Some exotic versions are rarely seen outside specialty shows, while others are readily available to the novice grower. Unlike the common stereotype, many types of orchids will thrive as houseplants, and don’t need to be kept in a greenhouse. The orchid you’ll choose to grow will depend on the environment in your home, as well as the way the plant looks.

Some people have very responsibly done research before watering their plant and are confused by recommendations they’ve found elsewhere that say to use only water at room temperature. Here at Just Add Ice Orchids, we love orchids and have tested our theory before offering it to others. We’ve found that those who follow our recommendation meet with orchid success!
Some saprophytic orchid species of the group Gastrodia produce potato-like tubers and were consumed as food by native peoples in Australia and can be successfully cultivated, notably Gastrodia sesamoides. Wild stands of these plants can still be found in the same areas as early aboriginal settlements, such as Ku-ring-gai Chase National Park in Australia. Aboriginal peoples located the plants in habitat by observing where bandicoots had scratched in search of the tubers after detecting the plants underground by scent.[Note 1]
The orchid plant is also unique in its morphology (form or structure). We can begin with the leaves and work our way down to the roots. The leaves of many orchids in cultivation are unique in that they are specifically designed for water conservation (as is true for almost every orchid structure). They have a heavy waxy leaf coating and specialized stomata (openings through which the leaf “breathes”) that help to prevent water loss during transpiration (the act of the plant “breathing”). Many orchids utilize CAM photosynthesis as well, which in essence means that the plants collect materials during the day and then process them at night.