Even experienced orchid lovers often only realize that the orchid is rotting when any help comes too late. Diseases such as heart or stem rot prove to be insidious, since an apparently healthy plant suddenly dies away. Read about the signs to look out for in your orchids and how to treat affected specimens. However, since rot almost always leads to death, preventative measures are still the best course of treatment.
Orchid rotting
If the orchid gets soft or even rotten spots, this is usually due to one of the two rotting diseases:
- heart rot
- stem rot
We will show you how to recognize the two types of damage and what you can do to combat the diseases.
heart rot
Heart rot is a typical phenomenon of monopodial growing Orchidaceae such as the popular Phalaenopsis (butterfly orchid) or the equally uncomplicated Vanda. These two species form a single plant sprout, from the center of which new leaves sprout alternately.
causes
Putrefactive diseases are always triggered by excess moisture, which in turn triggers the colonization of fungi or bacteria and the corresponding decomposition processes. These can be different pathogens, only the symptoms and consequences of the disease are the same. If the heart of the orchid begins to rot, standing water between two leaves or between a leaf and the bulb is often the cause. From here, the moisture gets inside, into the "heart" of the plant. Here the usually bacterial pathogens find the best growth conditions and multiply within a short time - the orchid rots from the inside out.
In addition to incorrect watering, these causes can also lead to excess moisture and thus to an outbreak of heart rot:
- too high humidity
- improper/too frequent dipping or spraying
- Condensation, orchid cannot "dry off" in between
- Pouring, dipping or spraying at the wrong time, e.g. B. in the evening
- little fresh air, e.g. B. in the terrarium
damage picture
The disease is characterized by the sudden dropping off of apparently healthy leaves, which detach from the plant at the slightest touch. Often the upper, i.e. youngest, leaves turn yellow first, whereby on closer inspection not only the lower, sometimes still green, leaves also say goodbye, but the cause of the problem can also be seen. The areas affected by the heart rot are
- colored black,
- wet,
- soft to mushy,
- smelling of rot.
If the disease has not progressed too far, only one or a few places are affected. However, the more time the pathogens have for their work, the more the rot spreads to other parts of the orchid - until it is finally completely rotted. The trunk can also be affected.
combat
Heart rot almost always leads to the death of the orchid, treatment is usually only possible at the very beginning of the disease. If only one or more small areas are affected and the roots are still healthy, you can try the following measures:
- Cut away diseased plant parts generously
- Disinfect interfaces
- dust with charcoal powder or fresh cinnamon powder
- keep plant dry
In most cases, however, rot is not recognized until it has penetrated deep into the heart of the plant. The orchid will no longer form any new leaves and will die sooner or later. The plant can no longer be saved and must be disposed of. However, do not throw them in the compost, but in the household waste. The plant pot must also be thoroughly cleaned and disinfected before being used again. Otherwise, there is a risk of other plants being reinfected, since the pathogen remains on the surface and does not die off with the plant.
tip: With a bit of luck, however, so-called stem children will develop, which you can separate and plant as genetically identical offspring. To do this, continue to care for the affected orchid as usual, although you should separate it from other plants. This prevents the pathogen from spreading to previously healthy specimens.
prevention
As always, prevention is the best medicine, so keep these pointers in mind when caring for Orchidaceae:
- water in the morning to allow water to dry off during the day
- Do not water in the evening or at night due to poor evaporation
- avoid high humidity in closed rooms
- air regularly
- do not leave water on or in the orchid
- do not water over the leaves/from above
- Dab off the water between the leaves or leaves and bulbs with paper or cotton wool
stem rot
The stem rot is quite similar to the described heart rot. Here, too, species such as Phalaenopsis or Vanda are primarily affected, which only form one plant shoot and let their leaves sprout one after the other from the middle. This disease is just as dangerous, since the affected plant almost always dies. However, there are some differences with regard to the damage and the causes - and thus, of course, treatment and preventive measures.
causes
The root rot is usually caused by a substrate that is too moist, whereby advanced heart rot can also develop into a trunk rot. Here, too, there is an excess of moisture or even wetness behind the disease, which ultimately leads to a strong proliferation of mostly bacterial pathogens. In addition, other causes lead to the typical damage pattern:
- constantly moist substrate that hardly dries in between
- excess water is in the planter
- Plant is potted too deep
- Trunk remains wet for too long after spraying, does not dry
- Plant does not dry off after diving
tip: In many places, experienced orchid keepers recommend submerging the plants rather than watering them. After that, however, you must drain them well so that excess water does not collect in the pot.
damage picture
While in heart rot the youngest leaf - the so-called heart leaf of the orchid - rots first, in stem rot the lower leaves first turn yellow and then fall off. Again, if the rot is advanced, all the leaves can suddenly be shed at once even with a gentle touch on the plant. Rotting spots are black, soft and damp, especially the trunk, the inside, of the plant.
combat
Rot diseases are insidious, as they are often recognized very late and therefore end in almost all cases with the death of the affected orchids. Stem rot is no exception, as once the inside of the plant has rotted and all the leaves have been shed, it will no longer sprout a new sweetheart. However, you do not have to hand over the specimen in question to the organic waste bin right away, because if the roots still appear healthy, offshoots, the so-called stem children, often form. Dust the rotten spots with powdered charcoal or fresh cinnamon powder, place the plant in fresh, dry substrate and wait a while. With a bit of luck, after a few weeks or months you will have a healthy, genetically identical offspring.
prevention
Since the treatment of rotting Orchidaceae is hardly successful, preventive measures are all the more important. These tips are especially useful:
- do not pour from above, but always onto the substrate
- Always remove excess irrigation water promptly
- Leave out the cachepot, this prevents the moisture from evaporating
- Keep orchid drier in winter
- Water less often and, above all, less, since moisture evaporates only slowly
tip: If the rot is still in the early stages, quick help in the form of repotting in fresh, dry substrate sometimes saves the affected plant. Charcoal or cinnamon powder disinfects the putrid areas and prevents further spread.