Root rot is one of the most common and dangerous plant diseases, affecting both indoor and outdoor plants. It is usually caused by waterlogging and leads to the roots rotting. Tropical plants such as Monstera, Philodendron, Anthurium, and Alocasia are particularly susceptible, as they are sensitive to constantly wet roots.
Once it has taken hold, root rot can quickly lead to the death of the plant. However, if you recognize the signs early and act correctly, there is often still a chance to save your plant.
What is root rot?
Root rot describes the death and decay of a plant's roots . This occurs when the roots are exposed to excessively moist substrate for an extended period and begin to rot.
Rot is often caused by fungi and bacteria that multiply rapidly in the damp environment. Once the roots are damaged, they can no longer absorb nutrients or water, which severely weakens the plant.
Which plants are particularly susceptible?
Tropical houseplants are particularly susceptible to root rot, including:
- Philodendron
- Monstera
- Anthurium
- Alocasia
- Syngonium
- Calathea
- Orchids
Herbs such as basil and mint , or vegetable plants such as tomatoes, can also be affected.
Causes of root rot
The most common cause of root rot is waterlogging , meaning excess water that cannot drain properly. However, there are other factors that increase the risk:
Overwatering
- If plants are watered too frequently or too much, the substrate remains permanently moist.
- Especially in winter, when plants use less water, incorrect watering can quickly lead to rot.
Poor drainage
- Incorrect substrate : Normal potting soil often retains too much water, while permeable mixtures with perlite, pine bark and coconut fibers prevent waterlogging.
- No or too few drainage holes : In pots without drainage, water collects at the bottom, which softens the roots and promotes rot.
Fungal and bacterial infestation
- Pathogens such as Pythium, Phytophthora and Rhizoctonia thrive in moist, poorly aerated soils and attack weakened roots.
Cold temperatures & humidity
- At low temperatures, the plant grows more slowly and needs less water – excess moisture cannot evaporate quickly enough.
- Very high humidity combined with wet substrate further promotes rot.
Symptoms and identification of root rot
Root rot begins in secret, as the first damage appears on the roots. However, there are clear signs that indicate a problem:
Visible signs on the plant:
- Yellow or wilted leaves : The plant appears sick and shows growth problems.
- Brown, mushy roots : Healthy roots are firm and white or light brown.
- Musty smell from the pot : A rotten smell is a sure sign of decay.
- Weak growth : The plant does not produce new leaves or allows existing leaves to droop.
- Fungal or mold infestation : White or black spots on the soil surface may indicate fungal infestation.
The root test
To be sure it is root rot, you should carefully remove the plant from the pot:
- Remove the soil and examine the roots.
- Healthy roots are firm, light in color, and elastic.
- Rotten roots are dark brown to black, mushy, and break easily.
Treatment of root rot
If the plant is already affected, there are several ways to save it. The sooner you act, the higher the chances of survival.
First aid measures
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Remove the plant from the pot
- Carefully remove the soil.
-
Cut off infected roots
- Remove all mushy roots using disinfected scissors or a sharp knife.
-
Disinfect root remnants
- Treatment with cinnamon, activated charcoal, or a fungicide can help kill bacteria and fungi.
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Fresh substrate and a clean pot
- Plant in fresh, well-draining soil and prevent waterlogging.
-
Watering correctly
- Do not water for a few days after repotting to allow the roots to recover.
Home remedies for root rot
- Cinnamon : Natural antiseptic against fungi.
- Activated charcoal : Helps to bind excess moisture and reduce bacteria.
- Chamomile tea : Can be used as a mild disinfectant for the roots.
Prevention of root rot
To prevent your plants from developing root rot in the first place, you should follow some basic care tips:
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Use drainage holes in the pot
- So that excess water can drain away.
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Choose a loose, permeable substrate
- A mixture of potting soil, perlite, pine bark and coconut fiber prevents waterlogging.
-
Adjust watering behavior
- Water only when the top 2-3 cm of soil are dry.
-
Improve air circulation
- Good ventilation prevents the growth of mold and bacteria.
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Avoid cool temperatures
- At temperatures below 15 °C, the plant's water consumption decreases.
Root rot is a serious plant disease primarily caused by improper watering and poor drainage. Early signs such as yellow leaves or weak growth should be taken seriously.
As soon as an infestation is detected, quick action is necessary: remove affected roots, repot the plant, and adjust watering habits. With proper prevention, root rot can be avoided, and your plants will remain healthy in the long term.
