Or, at the very least, get poor results…
1. Water it only with ice cubes. Some orchids sold at box stores come with instructions recommending watering with ice cubes. This is meant to discourage overwatering the plant and make looking after it sound super easy; however, ice cubes do not contain enough volume of water to thoroughly moisten the potting mix, and as the orchids in question are tropical plants, they don’t appreciate having ice and ice-cold water on their roots!
2. Allow the pot to sit in water. The easiest and fastest way to kill most orchids is to grow them too wet. Keep the pot sitting in water, and you will have a rotten plant before long. When in doubt, don’t water; always use pots that have drainage holes; and use a potting mix designed for orchids.
3. Ignore it for long periods of time. Orchids are not particularly high-maintenance plants, but every time you water (which is normally at least once per week), it is a good idea to inspect your plants for any insects or diseases, which are always easier to deal with early on.
4. Never fertilize it. Coming from habitats where nutrients are scarce, orchids are not heavy feeders. However, like all living things, they do require food to survive, and the potting media they grow in contain essentially no nutrients. Therefore, orchids should be fertilized once per week at half strength while in active growth. Failure to fertilize will eventually result in weak plants that will not flower, or will produce poor flowers.
5. Fertilize too heavily and too frequently. Orchids need fertilizer in light doses. Fertilizing heavily can result in burning of the roots and leaves, lack of flowering, and in some cases even stunted growth.
6. Put it in a dark area. Many orchids (in particular the ever-popular Phalaenopsis) grow well in low light situations. However, placing your plants in a dark corner away from windows and relying on ambient lighting from lamps is not sufficient for them to grow and flower. Orchids should be grown in a windowsill, near a large window that is unobstructed, or under grow lights.
7. Put it in direct afternoon sun in the summer. Most orchids are plants of the jungle, growing beneath a thick forest canopy. As such, while many enjoy bright light, direct afternoon sun in the summer will scorch their leaves and leave you with a cooked plant very quickly!
8. Expose it to freezing temperatures. Tropical orchids, as you might expect, will not tolerate freezing temperatures and can go into shock when temperatures drop below 8°C. If you are growing in a windowsill, make sure the leaves never touch the window in the winter, or you may get cold damage.
9. Expose it to extreme heat. When temperatures rise above 32°C, orchids begin to stress, and will start transpiring at a greater rate, meaning they will need plenty of moisture and humidity, as well as air movement, to keep them from collapsing. It is best to keep temperatures below this threshold to avoid damaging or killing your plants.
10. Never repot it. One of the most important parts of looking after an orchid is repotting it on a regular basis. Potting media decompose over time, losing their ability to drain and keep air around the roots. In turn, the roots will begin to suffocate and rot. Repotting should be done every 1-3 years, depending on the type of orchid and the type of potting media.