Have your orchid flowers (or flower buds) fallen off suddenly, and you’re not sure why? I can share your frustration! Even though I work at a garden nursery that supplies garden centers, this has happened to me. So, I made it my mission to find out why! I am fortunate enough to be able to speak to specialist orchid growers who gave me the low down on why flowers drop off.
In this article, I share with you everything I have been taught about maintaining orchid flowers and how to prevent them from dropping off…
Orchid flowers and flower buds fall off because of a sudden change in temperature or humidity. Orchid flowers and buds fall off due to low humidity or if the temperature increases or decreases suddenly, most often because of indoor heating in Winter or dry air from air conditioning.
I should highlight that orchids naturally drop their flowers after 6-10 weeks as part of a natural cycle.
As there are several reasons for this, Here I have summarized the most common reasons orchids drop flowers or develop flower buds:
|Reasons for Orchid Flowers and Flower Buds Falling off:
|Flowers fall off after 6-8 weeks:
|Most orchids have flowers that last 6-8 weeks (with optimal conditions) before falling off.
|Orchids prefer a temperature range of 66°F to 86°F (19°C to 30°C) during the day and 61°F to 66°F (16°C to 19°C) at night. If the temperature fluctuates significantly outside of the orchid’s typical range, this causes flowers to fall.
|Most houseplant orchids (Phalaenopsis or ‘Moth; orchids) require a humidity of at least 30% but preferably 40% or more. If the humidity is too low the orchids dry out, and the flowers and flower buds drop off.
|Orchids should be watered every 7 days with a good soak when in flower or when flower buds are developing. Underwatering dries out the orchids and causes the orchid to drop its flowers to conserve resources.
|If the potting medium is too damp from overwatering or the medium itself retains moisture for too long, the orchid’s roots can die back, and the flowers fall off.
|Repotting at the wrong time:
|Orchids should be repotted during Spring or Summer when the orchid is not in bloom. Repotting temporarily causes the roots to draw up moisture less efficiently from the potting medium, causing the flowers and flower buds to fall off.
Please keep reading to learn why orchids drop their flowers and how to prevent this from happening to your orchids…
1. Orchid Flowers Fall Off Naturally After 6-10 Weeks
The most popular houseplant orchids (Phalaenopsis, also known as ‘moth’ orchids) typically flower once per year (although they can flower more often in optimal conditions), and the blooms usually last for 6-10 weeks as long as the conditions are favorable.
Moth orchids can flower at any time of the year but typically form new flower spikes in the cooler Winter months, and the flowers are displayed in the Spring.
When the temperature cools at night, this signals to orchids that it is the right time to flower in their natural environment in time to display flowers for Spring and Summer.
Orchid flowers can drop 6-10 weeks or so as the orchid reacts to the changing seasons with differing levels of light and temperature. This is part of the orchid’s natural cycle and I can assure you it does not necessarily indicate a sign of stress.
Pro tip: Prune back the flower spike to about half an inch above an emerging node as orchids do not flower again from the same stem.
This helps to stimulate the orchid to grow a new flower spike from which to display more flowers. For exactly how to do this, watch this helpful YouTube video below:
(If your orchid is not flowering, then read my article, why is my orchid not blooming? for how to help stimulate more flowers).
Once the flowers have dropped from the stem (also known as a flower spike), they can turn yellow and dry, in which case, prune the stem back to the base of the orchid. Read my article, orchid stem turning yellow?
2. Fluctuation in Temperature- Orchids Flowers and Buds Dropping
One of the most common reasons for orchid flowers and flower buds dropping is because of a sudden fluctuation in temperature that is outside of the orchid’s usual temperature range.
This happened to me due to indoor heating in Winter, which suddenly increases the temperature, causing my flowers to drop.
Orchids can live in a range of 66°F to 86°F (19°C to 30°C), which is suitable for most indoor environments. However, orchids tend to get accustomed to specific environmental conditions.
A sudden change in temperature (whether it is hot or cold) outside of the orchid’s usual temperature range can cause enough stress for the orchid to sudden drop all its flowers or drop the flower buds before they have opened.
Sudden increases or decreases in temperature that affect orchids are most often caused by:
- Air conditioning.
- Sources of heat such as fires, central heating, and forced air.
- Drops in outdoor temperature can affect orchids on window sills or conservatories.
One of my orchids was too near my front door, and it got a cold blast of air every time I opened the door, which resulted in the flower buds dropping!
Orchids also prefer a cooler temperature in the evening than during the day, as this mimics the natural temperature cycle in their native environment.
We need to consider that typically, in houses, the temperature increases at night (particularly in Winter when indoor heating is on), which is contrary to the orchid’s preferred conditions.
The preferred temperature range at night for moth orchids (Phalaenopsis) is between 16-19°C (61-66°F). So it is important to find an area of the house that is out of the way of draughts and away from direct sources of heat.
Place your orchid slightly back from a cold window sill as if the leaves or flowers are in contact with the window at night; the cold temperature can cause the flowers to drop. This is a classic mistake I see often.
With consistent temperatures, the orchid flowers should last 6-8 weeks before falling off.
(Read my article, how to rebloom orchids indoors).
3. Low Humidity Causes Orchid Flowers and Buds to Drop
To understand why our flowers and flower buds drop off, we should consider how orchids grow in the wild…
Orchids are tropical plants that are native to forests in Asia, where the humidity tends to be in the range of 50% to 80%. The humidity in houses tends to be much lower at around 10%. The difference in humidity causes the orchid to lose water too quickly, and the orchid drops flowers as a sign of stress.
Whilst orchids are tropical plants, the popular Phalaenopsis (‘Moth’) orchids (these are the ones you see everywhere) have been cultivated so they can tolerate somewhat lower levels of humidity of around 30%, which is lower than its natural environment, but the orchid still requires more humidity than the air in most houses.
The humidity in houses can fluctuate fairly drastically for reasons such as:
- Air currents from air conditioning, forced air, draughts, and convection currents are caused by sources of heat.
- Central heating or indoor fireplaces lowers air humidity significantly.
Flowers dropping is one of the first signs that the orchid is stressed from low humidity, but low humidity also saps moisture from the leaves, aerial roots, and flowers, stressing the orchid so that the leaves can also wilt or turn brown as a sign of drought stress.
This happens to me because I live in a climate where I use indoor heating in the winter (which dries out the air) and air conditioning in the summer (which saps moisture from the leaves and flowers).
How to Solve it:
To prevent orchid flowers from dropping, we need to replicate the orchid’s preferred natural higher levels of humidity in the house by creating a humid micro-climate, which reduces drought stress and creates favorable conditions for orchid flowers to last longer.
I keep the orchid away from draughts, air currents, and sources of heat as this is contrary to the natural conditions.
There are three effective ways to create a humid micro-climate in your home that I have tried:
- Mist the orchid’s leaves flower and ariel roots every day.
- Place the orchid in a tray of water filled with pebbles (the pebbles keep the bottom of the orchid’s pot above the waterline so that moisture can escape from the bottom of the pot after watering to prevent root rot).
- Use an indoor plant humidifier that allows you to set the level of humidity exactly to the orchid’s preferred range.
For most houses, I recommend a combination of misting the leaves or placing the orchid on a tray of water filled with pebbles (the water evaporates around the orchid, which increases the humidity).
However, if you live in a particularly arid climate, then the best option is a plant humidifier (available at garden centers and on Amazon), as they are particularly effective at recreating the optimal conditions for orchids.
I also have a lot of success growing orchids in my bathroom as they love the higher levels of humidity!
Once the orchid is in a more humid environment, it can hold its flowers for longer, and any developing flower buds can emerge without the increased risk of dropping off.
4. Drought Stress Causes Flowers and Flower Buds to Drop
Orchids drop their flowers and flower buds if they experience drought stress due to low humidity and a lack of watering. The low humidity saps moisture from the leaves, roots, and flowers, and if the potting medium dries out completely, the flowers and flower buds drop.
From my conversations with specialist growers, they told me that Orchids require at least 40% humidity and should be watered at least once a week when in flower or while the flower buds are developing.
I discovered that what happens is the flowers drop off quite suddenly after a period of drought stress as the orchid cannot sustain them and drops the flowers to conserve its resources, so it can increase the chance of immediate survival.
Always water orchids with a generous soak so that excess water runs from the drainage holes in the base and all of the potting medium is evenly moist.
Pro tip: What I like to do is place my orchid’s pot in a basin of water for a few minutes as a different method of watering, as this is an effective way of ensuring the potting medium is evenly moist.
If the orchid is watered too lightly, then only the top inch or so of the potting medium becomes moist, and the water does not reach the roots properly where it is required.
This is assuming that the orchid is planted in a pine bark-based potting medium formulated specifically for orchids, as this has an aerated structure and emulates the growing conditions of the orchid’s native environment.
5. Watering Too Often- Orchid Dropping Flowers
Orchid roots are sensitive to overwatering as too much water excludes oxygen from the potting medium, which can interfere with the orchid’s ability to draw up moisture and nutrients. This causes dying roots and results in the flowers and flower buds falling off.
What I learned was that if the orchid’s roots are dying, then the orchid drops the flowers and flower buds to conserve its resources as it tries to survive and maintain the essential plant tissue, such as the remaining roots, leaves, and pseudo-bulbs, which often turn yellow as a reaction to overwatering.
Orchids typically require watering once every 7 days during Spring and Summer and once every 10 days in Winter (read my article, how to water orchids to learn how often to water orchids at different times of the year).
The top inch or so of the orchid potting medium should dry out slightly between bouts of watering.
Pro tip: I feel the potting medium with my finger to establish when the top inch has dried, as I have found this to be a much more reliable method than using a moisture meter.
If you are watering more often than once a week, then I can confirm you are overwatering your orchid, and this is likely the reason the orchid loses its flowers.
In addition to watering, what Iv’e found is the right potting medium is essential to create the optimal balance of moisture for your orchid.
Pine-based potting mediums are my favorite for orchids as they recreate the aerated, well-draining conditions in which orchids grow in their natural environment.
Orchids are epiphytic (grow in trees rather than in the ground) and quickly die back if they are planted in potting soil, as this excludes oxygen from around the roots and retains too much water, causing a dying orchid with flowers falling off.
(Read my article, how to revive a dying orchid).
I advise Repotting your orchid every 2-3 years as the pine bark or moss decomposes, causing it to retain too much moisture and less oxygen.
Once you have established the right water regime and repotted into pine bark the orchid should be able to keep its flowers if it flowers again.
6. Transplant Shock- Orchids Flowers Falling off
Have you repotted your orchid and found all the flowers have dropped off?
Repotting orchids whilst flower buds are developing can cause the flowers or flower buds to drop. I discovered that this is because repotting an orchid interferes with the root system’s ability to draw up moisture and nutrients from the potting medium. If the roots cannot draw up moisture efficiently after repotting, the flowers drop, which is a sign of stress.
The experts told me orchids should be repotted every 2-3 years as the potting medium decomposes over time (which retains too much moisture and reduces oxygen around the orchid’s roots). Still, repotting should be avoided if the orchid is in bloom or the flower buds are developing.
If the orchid experiences any kind of stress whilst it is flower or the flower buds are developing then the orchid prioritizes survival and drops any flower buds as flowers and flower buds require considerable energy and resources from the plant.
Stress from repotting usually is because the roots are disturbed from their established potting mix and cannot draw up water efficiently when they are repotted.
It is also best to repot orchids in pine bark-based potting mediums as they have the optimal structure to create the balance of moisture for orchids to thrive.
If the orchids are repotted into a moss based potting medium, then the contrast between the well draining pine bark and the comparatively higher moisture retaining moss often causes the flowers to fall off and dying roots.
It is possible to repot orchids at any time of the year, but the best time to repot orchids is in the Spring or Fall after they have flowered.
- Orchid flowers drop because the humidity is too low or the temperature is too high. Orchids are tropical plants that prefer high humidity levels and temperatures between 61°F and 86°F. Orchids drop their flowers if the temperature is too high or the air is too dry from indoor heating or air conditioning.
- Orchid flower buds fall off if there is a sudden change in temperature and humidity or if the orchid is underwatered or overwatered. If the potting medium dries out completely between bouts of watering, then orchids drop their flower buds as a sign of stress.
- Orchid flowers fall off if the potting medium dries out completely. If the orchid is not watered often enough or lightly watered, the flowers fall off as the orchid tries to conserve moisture. Water orchids every 7 days when in flower to prevent the flowers from falling off.
- Orchid flowers can fall off if they are watered too often. If the potting medium is consistently damp, then this excludes oxygen from around the roots and interferes with their ability to transport moisture and nutrients around the plant to support the display of flowers, which results in the flowers dropping off.
- Orchid flowers fall off if the orchid is repotted whilst in bloom. Repotting interferes with the orchid’s established root system and can temporally prevent the orchid from drawing up water efficiently. If the roots cannot draw up water properly after repotting, the flowers should drop to help conserve the orchid’s resources.
- Orchid flowers typically last 6-10 weeks before falling off. This is a normal part of the orchid’s cycle throughout the year and does not indicate anything is wrong with the orchid.