What Causes Root Rot in Hydroponics?

What Causes Root Rot in Hydroponics

Hydroponics is a system of growing plants without soil, using a nutrient solution instead. Environmental control is still required, just as it is when plants are grown conventionally. This growing method is becoming increasingly popular for its convenience and ease of monitoring. However, it does have its challenges, and hydroponically-grown plants are not immune to diseases like root rot. 

What is hydroponic root rot?

Root rot is a disease that causes the death and decay of plants’ roots and is caused by overexposure to wet conditions, disease-bearing pathogens, or a combination of the two. Fungi, bacteria and mold can infect the roots, especially in wet conditions, and infected plants struggle to absorb nutrients and water. Poor air circulation will exacerbate the condition, as the roots will not be exposed to sufficient oxygen. In hydroponics, where water is the growing medium, the roots of your plants still need sufficient exposure to air and oxygen, and/or well-aerated water, to prevent the development of diseases like root rot.

What causes root rot in hydroponics?

A common cause of root rot in hydroponics is poor circulation and insufficient water movement. This reduces the oxygen level in the hydroponics system and could lead to the plants’ death. Other causes of root rot in hydroponics are insufficient exposure of the roots to air, contaminated nutrient solutions or equipment, pests, and infected transplants. 

How to prevent hydroponic root rot

Maintaining a clean system. 

Keep your system decontaminated and sterilize the equipment, so that it does not become a breeding ground for harmful bacteria. Also ensure that there is no way for the nutrient solution to be contaminated with toxic substances. 

Cut the roots regularly. 

Your plants’ roots should be cut regularly to allow the nutrient solution and oxygen to pass through the system easily. Large roots could block essential movement and have a detrimental effect on the crop. 

Maintain the correct temperature for your hydroponics system. 

Keep the temperature below 75 degrees Fahrenheit. If the right temperature is not maintained, it could encourage the growth of bacteria that reproduce quickly in warmer conditions. Provide adequate ventilation if you are in a warmer region, and place your reservoir in a shaded area if your setup is outdoors.

Choose the appropriate pump. 

Promote aeration by using a reliable pump and adding air stones. Aeration is vital to a hydroponics system, since it increases the level of oxygen, which is essential to the roots. 

Use thick materials for the grow bed.

Use thick, dark materials for the grow bed to protect the roots from light-loving bacteria. These materials can minimize the amount of light that reaches the roots. 

Maximize beneficial bacteria to keep the plants healthy. 

Add beneficial bacteria to the hydroponics system to boost your plants’ health. This makes the plants less vulnerable to diseases, just as humans build a better immune system by taking vitamins and supplements. 

How to cure root rot in hydroponics

To cure root rot in your hydroponic system, switch off the system at once. Removing the infected plants without stopping the source is futile, since the culprit could be contaminated water and other healthy crops could also be infected. Pause the system for the time being while you manage the problem.

Clean the roots by washing them thoroughly with water to remove foreign substances. You should also gently cut away any infected roots from the plants. You will need to clean the entire hydroponics system and drain all the nutrient solution from the reservoir. Check and clean the grow bed and ensure that no dead plants are left behind that could contribute to further root rot. 

Monitor your plants for pests like fungus gnats, since these are vectors for pathogens that cause root rot. Make sure that the vents are filtered to keep out such pests. Also ensure you use only healthy transplants, since these can also introduce diseases and pests to your hydroponic system. 

It is not always necessary to dispose of plants infected with root rot. First check whether the crops are still worth saving. If only a small portion of the roots is infected, you can trim these off and have a good chance at saving your plants. Simply follow the previously-mentioned steps and set up your system again. 


Hydroponics is a popular method of growing plants, especially in urban areas, since it does not require the use of soil. However, some challenges accompany the management of such systems, and these include the threat of root rot. This is usually caused by poor circulation, overwatering, insufficient water movement or contaminated solutions and transplants. 

To prevent root rot in your hydroponics system, always keep a clean system, trim the roots regularly and maintain the right temperature, which is under 75 degrees Fahrenheit. Also, choose the appropriate pump, and maximize beneficial bacteria to keep your plants healthy. 

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