Orchids grow much like any other flower: Seeds are produced via pollination, the seeds germinate, seedlings grow and mature, flowering occurs and the plants reproduce. Still, there are some things that make orchids unique in how they grow, such as the fact that orchid seeds in the wild will not germinate without the help of a specific fungus. In addition, there is a wide variety of differences in growth stages across the thousands of different species of orchids. For example, some orchids bloom for months, while others, such as the ghost orchid, produce just one bloom one time per year.
Orchid growth begins with a seed. The seeds are tiny and light, because most orchids are air plants. Thus, the seeds are made to float in the air and land on the branches and trunks of trees. Orchids produce hundreds of thousands of seeds. However, the seeds do not have endosperm, and once they have landed, they need to be invaded by the mycorrhiza fungus in order to germinate. This is why most orchid seeds do not sprout. If the fungus does invade the seed, however, it will provide the nutrients needed for germination, while the seed provides the fungus with a home.
Once the seed has germinated, it may take a long time to grow into a young plant--up to seven years for some species. Most orchids, like the Cymbidiums, will develop a rhizome, then a pseudobulb. The pseudobulb develops from the rhizome, which is a horizontal, underground stem. The role of the pseudobulb is to store nutrients and water for the orchid.
From the pseudobulb will eventually develop a flower stem, which will grow vertically. Again, this can take anywhere from a few months to several years, depending on the species of orchid. Once the stem develops, leaves appear shortly thereafter. This foliage will use up the nutrients in the pseudobulb, causing it to shrivel up and die, while a new one forms further along the rhizome.
With the right conditions, including humidity, lots of sunlight, variations in temperature and proper watering, flowers will bloom on the orchid and pollination will occur. Most orchids are pollinated by insects, just like other flowers and trees. A few self-pollinate, such as the Ceratandra globosa. After several weeks, the ovules will develop seeds that can be as small as a grain of dust, and the cycle begins again.