Stem rot is a fungal infection affecting the stems of plants, including plants grown under hydroponic conditions. Symptoms are rotting and decay of the plant stems, usually seen after a plant has died. Treatments of stem rot in hydroponic systems are identical to treatment in other garden situations although the hydroponic nutrients need to be protected from the fungicides.
Diagnosing Stem Rot
Determining the cause of a plant's decline can be difficult. The early symptoms of stem rot can be similar to any number of ailments, such as lack of nutrition. Monitor the plant closely when problems start to determine when to begin treatment. The earlier proper treatment is started the less severe the treatment.
Pruning the Plants
The simplest step in combating stem rot is to remove all infected parts of plants with the disease. These leaves and stems are contaminated with a fungus and should not be composted. The removal of infected plant parts is often followed with a treatment of an antifungal agent.
Chemical Treatment of Stem Rot
Chemical fungicides can contaminate the water of a hydroponic system. The chemicals will ultimately be absorbed by the plants and possibly end up in the fruits or vegetables produced. If chemicals are used in a hydroponic system the bases of the plants should be covered with a waterproof material, as should other access points to the liquid nutrient. Spray fungicide sparingly.
Or you can prepare a mild fungicide. A mix of copper sulfate, lime and water has been used in French vineyards for centuries to treat fungus in grape plants. Known as the Bordeaux mixture, it is sprayed on the plants infected with the fungus. Steps to prevent the mixture from reaching the liquid nutrients should be taken. The mixtures should be used the same day it is mixed.
Preventing Stem Rot
Weakened plants are more susceptible to infections like stem rot. Stresses that can weaken plants include overcrowding, abnormal light exposure or temperature variations. The controlled conditions under which hydroponic plants are grown tend to limit these stress factors. However, if fungal infections occur take steps to remove the stress factors to help the plants recover.