Can a Phalaenopsis orchid's withered and yellowing buds still be saved? Here's how to remedy it
The most heartbreaking thing about growing flowers is when the flower buds you have been looking forward to suddenly wilt. Below, let's talk about the causes of and solutions for wilted and yellowing buds on Phalaenopsis orchids (moth orchids).
1. Environmental Causes
Temperature
Phalaenopsis orchids love a constant environment of 25-28°C during the day and 18-20°C at night. In winter, a heated room that swings between hot and cold, or direct air-conditioning airflow, will quickly turn the buds yellow from the chill; in summer, a balcony with blazing sun above 30°C will shrivel the buds directly. It is advisable to keep a thermometer and hygrometer on hand, keep the plant away from doors and windows in winter, and make sure the air conditioner does not blow directly on it in summer.
Light
If a Phalaenopsis orchid is placed in a bedroom corner or beside a cabinet where it gets no sun, the buds will gradually drop. It is advisable to place it on an east- or west-facing windowsill for bright indirect light in spring and autumn; in summer, a gauze curtain must be drawn to avoid the scorching sun from 10 o'clock to 16 o'clock, otherwise the buds can easily develop black spots from sunburn.
Humidity
In heated rooms in the north and air-conditioned rooms in the south, the air is dry, and Phalaenopsis buds lose water quickly and easily become shriveled and yellow. The easiest solution is to turn on a humidifier and keep the humidity at 50%-70%; or place a basin of water under the pot and prop the pot up on a few stones. Note! Do not spray water directly on the buds, or they will rot.
Repotting
Do not rush to repot a Phalaenopsis orchid you just bought online. Leave it in its original pot in bright indirect light to acclimatize for 7-10 days, during which do not fertilize and only water the surface sphagnum moss. Moving it around frequently or changing it into a pretty pot will cause the buds to wither directly because of the sudden change in environment.
2. Plant-Related Causes
1.Root rot
If the sphagnum moss stays wet all the time and, when you pull it apart, you see roots that are black and smelly, immediately take the plant out of the pot, cut off the rotten roots, apply carbendazim to the wounds, and repot it in fresh sphagnum moss. Remember! Never repot during the flowering period; if you absolutely must, keep the root ball intact, and after repotting water it to settle the roots, then let it rest.
2. Nutrition
Phalaenopsis orchids need a great deal of nutrition to bloom. If you do not fertilize for a long time, or only water with tap water, the buds will certainly shrivel. During the bud stage, water once a week with monopotassium phosphate (1 gram diluted in 1 liter of water); for routine care, sprinkle a dozen or so granules of slow-release fertilizer on the pot surface each month, and apply light, frequent feedings.
3. Pests and diseases
Mealybugs: dense little white spots on the undersides of the leaves; wipe them clean with a cotton swab dipped in alcohol
Spider mites: yellow spots on the leaves, plus webbing; spray with abamectin diluted in water, 3 weeks.
Anthracnose: if black spots appear on the buds, cut them off immediately, spray thiophanate-methyl to sterilize, and open the windows every day for ventilation.
3. Points to Note
Watering: water thoroughly only after the sphagnum moss turns white; water less in winter, and water in the morning and evening in summer
Ventilation: open the windows 1 hour a day, but do not let cold wind blow directly on the plant
First aid: if you notice the buds have wilted, first move the plant to bright indirect light, cut off the withered buds, stop fertilizing and observe for 3 days
Prevention: drench the roots with carbendazim once a month to prevent both pests and diseases