How to Treat Root Rot in Hydroponic Plants

Written by Naomi Meza


Posted on July 25 2022

Keeping your hydroponic garden healthy is different than keeping a traditional soil garden thriving.


Related Post: How to Grow Your Best Hydroponic Tomatoes


However, both types of gardens have the same challenges with root rot. Knowing how to treat root rot for hydroponic plants can save you a lot of headaches, especially if you know the signs to look for.

One benefit of this form of gardening is that the roots of the plants are visible, so you can detect root rot early and treat it.

What is Root Rot? 

Root rot in plants

Unlike root rot in traditional gardens, which is caused by soil that's too wet, root rot in hydroponic plants is caused by a water-borne fungus called Phytophthora, which thrives in oxygen-poor and damp environments.

The fungus grows on the plant's roots, blocking nutrient absorption and eventually killing the plant.

Unfortunately, the fungus often spreads to other plants in the planter or connected system through spores that dissipate in the water.


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What Does Root Rot Look Like?

Hydroponic lettuce plant with healthy roots

Stopping root rot in your hydroponic garden starts with being able to identify it.

Infected roots feel slimy, with an earthy smell that you typically don't have in hydroponic gardens.

Why is Root Rot a Problem?

Hydroponic lettuce plants with healthy roots

Root rot not only stunts the growth of your plants and eventually kills them, but it can significantly affect your entire gardening system.

Because the Phytophthora fungus spreads via spores, the entire system can eventually get contaminated. 

PhytophthoraI spores can lay dormant for several months, colonizing dying roots and dispersing through polluted water, re-used growing materials, or even through the contaminated system.

Even the equipment you use to tend your garden can become contaminated, and you may reintroduce the spores back into your system.


Related Post: Is it Possible to Build Your Plant's Immune System?


What Can You Do to Prevent Root Rot?

Air bubbles under water

Preventing root rot is the key to the best hydroponic crops. Proper oxygen levels in your hydroponic planters can help reduce the chances of root rot.

Make sure that your system has enough aeration. You can use both air stones and additional hoses to infuse and control the oxygen in your DWC system.

Make sure to monitor the O2 levels regularly and adjust if needed.

Temperature control is the other critical step in preventing root rot.

The warmer your nutrient solution is with oxygen, the less oxygen there is left for the plants to take in, creating better conditions for root rot to set in.

How Can You Fix Root Rot?

Person holding hydroponic lettuce plant showing healthy roots

1. First, remove any dead matter from your plants and discard it from the growing room.

2. Then, remove the plants and clean them over a sink, gently washing away the slimy coating that the PhytophthoraI fungus creates on the roots.

3. Next, clean the entire growing system carefully, removing all spores from the fungus before reintroducing the plants. It's a good idea to sterilize the growing equipment, too.

4. Finally, you may wish to add Potassium Sulfate to your growing system to nourish your plants and strengthen their immune system. 

Potassium supports many of the vital internal functions at work in plants, including the ability to respond to foreign bodies like various types of plant pathogens.


Potassium Sulfate Fertilizer From Greenway Biotech Can Help Your Hydroponic Root Rot Problems

We offer a wide array of fertilizers and treatments for your plants.

Browse our water soluble fertilizer collection, including Potassium Sulfate, to help root rot.

Our Hydroponics Bundle is also a great choice to add to your hydroponics crop if you want healthier. stronger crops with higher yield. You can find this bundle at the link above. 

Happy growing!



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