I wish I could tell you exactly how often to water your phalaenopsis orchids and how much water to give them and be done with this post. Unfortunately, there is no one size fits all answer. When it comes to watering any plants there are lots of factors to consider that’ll make the amounts and regularity vary. I’ll go over all those factors so you can see what will be the best for your own situation. 

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 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.
Special thanks to David Banks of Australia, Christian Kirsch; Dr. Rudolph Jenny, Peter O'Byrne***, Eric Hagsater***, Lisa Thoerle***, Mario Blanco***, Mark Whitten***, Adam Karremans, Hakan Halander****; Daniel Jimenez***, André Schuiteman***, Dr. E.F. de Vogel, Jaap Vermeulen, Rick Barry, Dr. Guido Braeme, Rogier Van Vugt; Rene Dishong, Tom Ballinger, Mac & Helen Rivenback; Dr Rubin Salueda; Rafael Govaerts***, Padre Pedro Ortiz, Dr Leslie Garay, Vena Read, Charles Lamb, Donald Tan of Malaysia, Joseph Dougherty, Dalton Holland Baptista, Rick Cirino; Prem Subrahmanyam, ROMAN MARUSKA Czech Republic, Michael Coronado, Alejandro Taborda, Greg Butler and Oak Hill Gardens, Bill Bergstrom and Bergstrom Orchids, Donna Nash, Oliver Lenhard, D. E Vermeullen, Americo Docha Neto, Richard Korber, Carl Withner, Mark Nir, Ekkehard Schwadtke; Dr Eric Christenson, Dave Alford, Igor Zhuravlev, Tony Watkinson, David Hunt, Jean Marie Vanderwinden, Glen Ladnier, Jeffrey W. Tucker, Jorge Alejandro Paulete Scaglia, Scott McGregor, Wilella Stimmell, Eric Thiessen, Geert Volckaert, George and Kathy Norris***, David Alford, Eric Hunt, Peter O'Byrne, Allen Black, Helen Milner, Al Pickrel, Greg Riemer, Marcia Whitmore, Phillipe Musschoot, Wilford Neptune, Jean-Claude George, Tony Walsh, Greg and Kerri Steenbeeke and their Orkology Kreations Website, Jim Hamilton, Robert Fuchs and RF Orchids, Gene Monier and JEM Orchids, Jerry Bolce, Andy's Orchids, Stephen Jones, First Ray Orchids, Robert Weyman Bussey, JEM Orchids, Carlos Hajek and his Peruvian Orchid Page, Bill Morden, David Morris, Noble Bashor, Patricia Harding, Nina Rach, David Haelterman; Craig Cooper, Rocky Giovinazzo, David Friedman, Bill Pinnix, Troy C. Meyers, Linda's Orchid Page, Pierre-Alain Darlet*, Guy Cantor, Tropical Orchid Farm in Maui, H&R Nursuries, Lois Greer, Ichiro "Haru" Ohsaka and his Bulbophyllum Page, Mauro Rosim from Brazil, A World Of Orchids, Bruce Norris of Canada, Nick Doe, Neville De La Rue, Nelson Barbosa Machado Neto, Jeff Aguillon, Dale and Deni Borders, Eka Mulja Tjipta, Rick Barry, Manfred Schmucker, Uri Baruk, Mike and Candy Joehrendt, Dan and Marla Nikirk, Walter Orchard, Christer Carlson; Guillerrmo Angulo, M. Max, Paula Vagner, Tennis Maynard, Greg Allikas, Malcolm Thomas, David Morris, Jacques Deschenes, Lourens Grobler; Gary Yong Gee; José Castaño Hernández; Judd and David Janvrin* for their photo and text contributions.
Phalaenopsis, the Moth Orchid, is one of the most commonly available and easiest to grow orchid genera. It is an especially good choice for beginners to orchid growing. They have large, showy flowers that come in a wide variety of colors. Most species have several flowers per stem, but some have more, and others have as few as one or two. There are a great many hybrid varieties on the market.
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 over 300 species, this type of orchid is well-known but not as common as people think, in part because only a few of the species consist of showy flowers that catch people’s attention. The ones that do, however, come in colors such as yellow with white tips and dark red edges, or dark red with wide white stripes. They contain three separate lobes and beautiful, narrow leaves that perfectly complement the petals.
The seeds are generally almost microscopic and very numerous, in some species over a million per capsule. After ripening, they blow off like dust particles or spores. They lack endosperm and must enter symbiotic relationships with various mycorrhizal basidiomyceteous fungi that provide them the necessary nutrients to germinate, so all orchid species are mycoheterotrophic during germination and reliant upon fungi to complete their lifecycles.
^ Guillaume Chomicki; Luc P.R. Bidel; Feng Ming; Mario Coiro; Xuan Zhang; Yaofeng Wang; Yves Baissac; Christian Jay-Allemand & Susanne S. Renner (2015). "The velamen protects photosynthetic orchid roots against UV‐B damage, and a large dated phylogeny implies multiple gains and losses of this function during the Cenozoic". New Phytologist. 205 (3): 1330–1341. doi:10.1111/nph.13106.
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.
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. 
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