The indoor types of orchids, including cattleya and phalaenopsis orchids, produce flowers that last months at a time. When these houseplants start blooming, the flower show continues for a long window—from four to 16 weeks. Cymbidium orchids produce up to 35 flowers per blossom spike, and each spike lasts up to eight weeks. Phalaenopsis orchid flowers can linger from 80 to 120 days.  
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.
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.
With over 1,000 pure species and many hybrids, this type of orchid is petite and attractive. They need a lot of bright light in order to grow and thrive, and if grown indoors, you may even need artificial lighting of some type. The Epidendrum orchid comes in colors such as pink and dark orange with yellow throats, and if treated right, it will bloom year after year.
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. 

Sympodial: Sympodial orchids have a front (the newest growth) and a back (the oldest growth).[5] The plant produces a series of adjacent shoots, which grow to a certain size, bloom and then stop growing and are replaced. Sympodial orchids grow laterally rather than vertically, following the surface of their support. The growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. While a new lead is developing, the rhizome may start its growth again from a so-called 'eye', an undeveloped bud, thereby branching. Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil.

Pollinators are often visually attracted by the shape and colours of the labellum. However, some Bulbophyllum species attract male fruit flies (Bactrocera spp.) solely via a floral chemical which simultaneously acts as a floral reward (e.g. methyl eugenol, raspberry ketone, or zingerone) to perform pollination.[8] The flowers may produce attractive odours. Although absent in most species, nectar may be produced in a spur of the labellum (8 in the illustration above), or on the point of the sepals, or in the septa of the ovary, the most typical position amongst the Asparagales.
Orchid flowers are all bilaterally symmetrical with three petals and three sepals. Their seeds develop in capsules and are extremely tiny, sometimes mistaken for dust or spores. Because the seeds are so small, they don’t contain enough nutrition to grow a new plant themselves, so they develop a symbiotic relationship with fungus, which provides the nutrients for them to grow.
Oncidium, perhaps more accurately the oncidium alliance, are a group of plants from South America that span a wide range of habitats. Inside the oncidium alliance there are a number of genera that hybridize freely to create what we call intergeneric oncidium hybrids. These can come in all sorts of shapes and sizes but are generally characterized by large quantities of small to medium flowers borne on a branched stem that generally forms a Christmas-tree shape. The most commonly identified Oncidium are the yellow “dancing lady” type.
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.
Orchids have become very popular houseplants in recent years, with their delicate blooms adding elegance and allure to any room. But for beginners, knowing how to water orchids may seem a bit daunting, since they are unlike other common houseplants. This article is going to focus on how to water phalaenopsis orchids. These are also called moth orchids, and are one of the most popular and widely available varieties of orchid.
Once you develop more than a passing interest in orchids, you will quickly notice how diverse this exotic plant family is. Encompassing genera that yield both the vanilla you love to bake with and fragrances you love to wear, each flower has unique characteristics and care requirements. Compare your plants to some of the most commonly cultivated orchids to help you determine what type of orchid you are growing.