The difference between an underwatered orchid and an overwatered orchid is that the roots turn brown, with a rotting texture and a bad smell due to root rot, because of overwatering, whereas underwatered orchid roots shrink in size and have a shriveled, gray appearance.
Moth ‘phalaenopsis‘ orchids (the most common species of houseplant orchid) store moisture in their leaves and roots, so when the orchid is underwatered, the orchid draws upon these moisture reserves causing the roots to shrivel and the leaves to wrinkle.
Here is a reference table for the key differences between over and underwatered orchids:
|Healthy Orchid Appearance:||Overwatered Orchid Symptoms:||Underwatered Orchid Symptoms:|
|Roots: The roots of healthy orchids are green after watering and fade to a light gray color in between bouts of watering. The roots should feel plump and firm.||Roots: Overwatered roots turn brown, with a mushy texture, rotting appearance, and a bad smell. Eventually, the roots die back and turn papery and hollow.||Roots: Underwatered orchid roots start to shrivel in appearance and turn gray but they do not have an unpleasant smell. Severely underwatered roots die back and turn papery and hollow.|
|Leaves: The leaves appear plump, firm, dark green, and should be fairly upright, rather the horizontal or drooping.||Leaves: Overwatered leaves droop and turn yellow, often with brown spots, which indicates fungal disease.||Leaves: Underwatered leaves appear wrinkled at first and eventually also wilt and turn yellow.|
|Flowers and flower buds: Orchids can display flowers, at any time of year if the conditions are favorable, but they often flower more in the Spring and Summer.||Flowers and flower buds: Flowers drop off overwatered orchids, prematurely due to stress.||Flowers and flower buds: Flowers also drop off underwatered orchids prematurely due to drought.|
Note that growth slows down considerably if the orchid is underwatered, whereas growth tends to stop and the orchid deteriorates more quickly due to root rot, caused by overwatering.
It is much easier to revive an underwatered orchid than an overwatered orchid.
Keep reading for how to avoid over and underwatering orchids and how to fix your orchid…
How to Tell if an Orchid is Overwatered
Symptoms of an over-watered orchid are: The roots are brown soft and mushy with a bad smell, and the leaves turn yellow and brown with a wilting appearance. With consistent overwatering the roots turn from brown and mushy to shriveled and papery white, which indicates the roots have died back. The buds and flowers may also fall off.
There is a lot of overlap between the symptoms of overwatered and under-watered orchids, so the key way to tell whether your orchid is overwatered rather than underwatered is to look at the roots and feel the potting medium.
Healthy orchid roots appear green or light grey, feel firm, and do not have a notable smell.
When orchid roots are in overwatered or boggy soil, they develop root rot and fungal diseases, which turn the roots brown and soft with a rotting appearance and a bad smell.
As the roots rot and die back they turn shriveled and to a papery, gray white color, which indicates the root is dead.
If the orchid’s roots are dying then they can no longer uptake water or nutrients to transport around the plant to the flowers, stems, and leaves which causes the leaves to turn yellow and wilt with a dying appearance.
The leaves often turn yellow with brown spots, which usually indicates fungal disease, as a result of overwatering.
The flowers are also very likely to fall off if a significant number of the roots are dying.
Orchids should only be watered when the potting medium has been allowed to dry slightly. Typically this means orchids should only be watered every 7 days.
If you are watering your orchid more often than 7 days and the potting medium is always damp, then you are overwatering your orchid.
It is important to highlight that overwatering alone may not be the only cause of the orchid dying.
A good watering schedule needs to be in conjunction with good drainage. It is imperative that moth orchids are planted in a special orchid potting mix, composed of pine bark.
This recreates the typical drainage conditions of the orchid’s native environment, allowing water to drain easily after watering and allowing air to circulate around the roots.
The problem is organic potting mediums decompose over the years which turns the pine bark pieces into compost, which retains too much moisture and restricts airflow around the orchid’s roots, resulting in an over-watered, dying orchid.
It is also important to plant orchids in pots with lots of drainage holes in the base and to empty any saucers and trays, underneath the pot regularly to avoid the symptoms of overwatering.
How to Fix Overwatered Orchids
To fix overwatered orchids, reduce the frequency of watering, cut away any dying brown roots with a sharp pair of pruners, repot the orchid into a new pot with an orchid potting medium to improve drainage, and mist the leaves.
- Reduce how often you water your orchids to about once every 7 days. The potting medium should dry out slightly between each bout of watering. Once the top inch of the potting medium feels dry, give the orchid a generous soak. This soak-and-dry cycle of watering replicates the conditions in its native environment and meets the orchid’s water requirements, without risking root root rot fungal disease.
- Take the orchid out of its pot and inspect the roots. Roots that have just been watered are green and they should be slightly gray but yet still feel firm during their watering cycle. If the roots are brown, smelly and clearly rotting, then snip the roots back with a sterile pair of pruners back to healthy growth or back to the base of the plant. Wipe the blades with a cloth soaked in disinfectant between each snip, to prevent potentially spreading fungal pathogens from diseased, rotting roots to roots that are otherwise healthy.
- Repot the orchid in a special orchid-based potting medium. Pine bark-based potting mediums are best for moth orchids, as they absorb enough moisture from the orchid’s roots, yet create a porous well-draining soil structure to allow excess water to drain away easily. It is important to replace the potting medium if the roots are rotting.
- Mist the orchid’s leaves roots and stems frequently after repotting. Orchids are native to tropical climates so misting the leaves can increase the humidity and reduce stress on the orchid after repotting.
- Repot your orchid every 2 or 3 years to mitigate the effects of overwatering. Orchid potting mixes decompose over time which makes the potting medium more compact and increases moisture retention, whilst decreasing the amount of oxygen around the roots and results in the symptoms of an overwatered orchid. Repot your orchid in a new potting medium in the Spring, when the orchid is at its most resilient.
- Ideally plant your orchid in a clear plastic pot with lots of holes in the base and side of the pot. Clear plastic pots allow you to see the roots, so you can see when they are healthy (green to light gray with a firm texture and plump appearance) and see if they are looking overwatered or underwatered. The holes in the side of the pot also help with air circulation, to keep the roots healthy. You can then place the plastic pot inside a larger, outer decorative pot.
- Avoid allowing saucers, trays, and outer pots to cause water to pool around the bottom after watering. Empty anything underneath the orchid’s pot to avoid root rot due to overwatering.
(Read my article, How to Care for Orchids)
Do not remove any yellow leaves as they are likely to die back and fall off on their own. Removing them when the leaf is still attached can cause additional stress to the already overwatered orchid.
Transparent plastic pots also have an additional benefit for saving the overwatered orchid. Moth orchids are very unusual in that their roots can also photosynthesize (provide energy for the plant through sunlight) which is usually the function of leaves. (Read my article, choosing the best pots for orchids).
As overwatering can cause leaves to turn yellow and die back, they can no longer photosynthesize.
The roots of the orchid in their clear plastic pot can attain enough light and therefore energy which allows for new green leaves to emerge so that the overwatered orchid can be saved.
(Read my article, how to water orchids).
How to Tell if an Orchid is Underwatered
Symptoms of an underwatered orchid are: The growth is stunted, and leaves start to wrinkle with a wilting appearance. The flowers and flower buds drop off or do not develop at all. The orchid’s roots shrink, and turn white and papery.
However the key difference between an underwatered and overwatered orchid is that underwatered orchid roots shrivel up, and turn papery but they do not turn brown or feel mushy or rotten.
Brown, rotting roots is exclusively as a result of overwatering and poor drainage.
Therefore if the orchid’s roots have turned from a plump, firm appearance to a shriveled appearance, but do not show any signs of rotting, turning brown, or smelling foul, then your orchid is underwatered.
Orchids store moisture in their roots, which is why they should feel firm if properly watered.
An underwatered orchid draws upon the moisture reserves in the roots causing them to shrivel, which is why shriveling, gray roots are usually the first sign of an underwatered orchid.
Orchids should be watered when the potting medium is slightly dry. If the potting medium dries out completely between bouts of watering, then your orchid is definitely underwatered.
Orchid may also be watered with the right frequency (around every 7 days) but still suffer from underwatering if it is watered too lightly.
Orchids should be watered with a generous soak, so that the potting medium is evenly moist.
If the orchid is watered too lightly, then only the top inch or so of the orchid’s potting medium becomes moist and the orchid’s roots cannot access the moisture they require which results in an underwatered orchid with shriveled roots.
Underwatering can also be compounded by other factors such as:
- Low humidity (orchids need high humidity and should be misted or placed in a humid room, such as the bathroom).
- High temperatures (orchids prefer a temperature range of 55°F (12°C) at night and 75°F (23°C) during the day, if the temperature is too warm the potting medium dries out too quickly and the orchid displays symptoms of underwatering).
- Draughty areas or air flow from air conditioning or forced air (strong air currents can sap moisture from the orchid leaves and potting medium and result in an underwatered orchid).
How to Fix and Underwatered Orchid
To revive an underwatered orchid, give the orchid a good soak so that the potting medium is evenly moist. Mist the leaves and aerial roots to increase the humidity and snip back any roots that have turned white and died back.
- Place the orchid in a basin of water for 10 minutes, ensuring the roots and potting medium are submerged. If the orchid has been chronically underwatered, this is the best way of immediately hydrating the roots and ensuring the potting medium is able to absorb water. The roots should start to plump up and turn green.
- Mist an orchid’s underwatered leaves, stems, and ariel roots to increase the humidity. Mist the leaves every day whilst the plant is visibly underwatered. Increasing the humidity with misting replicates the humid conditions of the orchid’s native environment to counteract dry indoor air and to stop the orchid from losing moisture through the leaves. Or you can buy a plant humidifier which can benefit other indoor tropical houseplants.
- Snip away any roots that have turned hollow and papery with a sharp pair of pruners. Slightly underwatered orchid roots shrivel and turn gray, whereas dead roots are papery and white and do not recover. Whilst not essential, it is best practice to snip these dead roots off as they do not support the orchid and it is best that they do not decay in the potting medium.
- Place your orchid away from any direct sources of indoor heating. Whether it is the dry air current of forced air, air conditioning, or near radiators, place the orchid on the other side of the room. Orchids often tolerate room temperature, but high temperatures create dry conditions which is contrary to their preferred tropical conditions.
- Always water orchids with a thorough watering to ensure the potting soil is evenly moist. Watering orchids with a good soak is essential to ensure that the roots can access the moisture they require. One of the most common causes of underwatered orchids is watering too lightly, so always use enough water, so that excess water trickles from the drainage holes in the base.
- Water the underwatered orchid when the top of the potting medium has started to dry out. Typically this means watering around every 7 days. It is important to wait until the top of the potting medium is dry, to avoid going from one extreme to another, with overwatering.
It is much easier to save an underwatered orchid, rather than an overwatered orchid. Keep misting the leaves, and roots diligently every day to promote recovery. Underwatered orchid roots should turn from shriveled to a plump texture.
The leaves can often revive once a good watering schedule has been established and misted regularly, turning plump again from a wrinkled appearance.
Sometimes some individual leaves turn yellow and drop off which isn’t necessarily an indication that the orchid is dying as new leaves can emerge during active growth once the orchid has more favorable conditions.
Avoid using any orchid fertilizer whilst the orchid is underwatered as this can promote growth when the orchid is already stressed.
(Read my article, how to revive a dying orchid).
- The best way to tell if your orchid is over or underwatered is by looking at the roots. Underwatered orchid roots turn gray and shrivel in appearance, whereas overwatered orchid roots turn brown, soft, and mushy, with a rotting appearance and an unpleasant smell.
- To save an underwatered orchid, give the potting medium a thorough watering, mist the leaves roots, and leaves every day to increase the humidity, and keep the orchid away from sources of indoor heating or air currents from air conditioning and draughts.
- To save an overwatered orchid, snip back any brown mushy roots with a pair of pruners, replace the potting medium with a pine bark-based potting mix, and only water the orchid when the surface of the potting medium is dry.