The Phalaenopsis orchid, often called the Moth Orchid, is the most common houseplant orchid. These orchids are epiphytes, meaning they naturally grow attached to trees in tropical environments, with their roots exposed to air rather than buried in dense soil. This aerial root structure requires a specialized approach to hydration, emphasizing thorough watering followed by rapid drying. Mastering the proper watering technique is the most important factor in maintaining a healthy Phalaenopsis orchid.
Indicators That Your Orchid Needs Water
The most reliable way to determine when to water is by observing the orchid’s roots, which are typically visible through the clear plastic pot. Healthy, dry Phalaenopsis roots are covered by a spongy outer layer called velamen, which appears a silvery-gray or whitish color. Once the roots are fully hydrated, the velamen becomes saturated, turning the roots a plump, vibrant green. When the roots transition back to that light silvery-gray color, it signals that the plant is ready for a drink.
You should also examine the potting medium itself, which is usually a bark mix or sphagnum moss. If the bark chips feel dry and light, or if the sphagnum moss feels crunchy or springy, it is time to water. A secondary indicator is the “weight test,” where you lift the pot to gauge its moisture level. A recently watered pot will feel noticeably heavier than a dry one, allowing you to quickly judge if the moisture has evaporated sufficiently.
Essential Watering Techniques
The most effective method for watering a Phalaenopsis is a thorough soak, which mimics the deep rain events of its natural habitat. Place the pot into a sink or container and pour lukewarm water over the medium until saturated, or submerge the pot up to the rim for 10 to 20 minutes. This allows the roots and potting material to fully absorb moisture.
After soaking, allow all excess water to drain completely from the pot. Phalaenopsis roots require air circulation, and standing water quickly leads to root suffocation and rot. When top-watering, be careful not to let water collect in the “crown”—the central point where the leaves emerge—as this moisture can cause crown rot, which is often fatal.
Water quality is a consideration; while many orchids tolerate tap water, using distilled water, reverse osmosis water, or rainwater prevents the buildup of mineral salts. Some growers advocate for the “ice cube method,” placing a few ice cubes on the potting medium once a week. Although this method does not immediately harm the orchid, it is inconsistent and does not effectively flush out accumulated salts, which is a benefit of a deep soak.
Adjusting Watering Based on Environment and Season
A fixed watering schedule is unreliable because the rate of water evaporation is influenced by the surrounding environment. During periods of active growth, typically the warmer months, the orchid’s metabolism is faster. Higher temperatures and lower humidity cause the potting medium to dry out quickly, meaning the orchid will need more frequent watering, sometimes twice a week.
Conversely, during cooler winter months, the orchid’s growth slows, requiring less water. The potting medium takes longer to dry, so reduce the watering frequency to prevent the roots from remaining saturated. If you use a humidifier or grow the orchid in a bathroom, the increased ambient humidity will also slow the drying process, necessitating less frequent watering.
The type of potting medium also dictates how often you water.
Potting Medium Considerations
A medium composed primarily of orchid bark chips drains rapidly and holds less water, requiring more frequent watering, perhaps every seven to ten days. Sphagnum moss is highly moisture-retentive and can stay wet for much longer, sometimes requiring water only every ten to fourteen days or more, depending on the environment.
Identifying and Treating Improper Watering Issues
The two most common issues resulting from improper watering are root rot (overwatering) and dehydration (underwatering). Root rot is indicated by roots that are brown, black, and mushy, often accompanied by floppy, listless leaves that look wilted despite recent watering. This occurs because the rotten roots can no longer absorb water effectively.
To treat root rot, unpot the orchid, sterilize a cutting tool, and prune away all the dark, soft, or hollow roots, cutting back until only firm, healthy tissue remains. Repot the plant in fresh, well-draining medium and a clean pot, then withhold water for several days to allow any cuts to heal. Dehydration results in silvery roots that are dry and brittle, along with shriveled or wrinkled leaves.
A dehydrated orchid can often be revived with a deep, extended soak, sometimes for several hours or overnight, to allow surviving roots to fully rehydrate. While the roots will plump up, severely wrinkled leaves may not fully return to their smooth state. The appearance of new, firm leaves signals a successful recovery and a return to a proper watering routine.