seedling damping off hydroponics

Damping Off, The Hydroponic Seedling Killer

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While not as common as in soil gardens, under the right conditions damping off may affect seeds and seedlings of hydroponic gardens. Knowing what damping off looks like can keep it from spreading in your garden, but knowing how to prevent it is the real key.

damping off kills hydroponic seedlings

What Exactly Is Damping Off?

Damping off is a general term, used when a pathogen attack kills a seed or seedling. There are several different pathogens that could be the culprit. These molds and fungi weaken the seedling, making it more susceptible to being taken over by diseases and pests. While less common in hydroponics, since it’s typically a more sterile growing area, it can show up in when seeds and seedlings are kept in certain conditions.

How To Tell If Your Plant Is Suffering From Damping off

Do you think you’re seeds or seedlings are being affected by damping off? Here are a few signs to look for:

Fluff or web-like growth on seeds or seedlings

Seeds that never germinate or may germinate, but never break above the grow medium.

Seedlings’ stems may become thin and tough, often referred to as “wire stem”, at the base of the plant stem. This typically rots, eventually causing the seedling to collapse over.

The seedling’s root system and or leaves are turning brown and mushy.

How To Prevent Damping Off From Killing Your Hydroponic Seeds & Seedlings

The goal is to prevent damping from occurring while seeds are germinating and seedlings are getting established. Once a plant has established a healthy leaf and root system, it builds a  protective layer, making it less likely to be affected by the pathogens that cause damping off. There is no cure for damping off, so if you see it in your seeds or seedlings you should remove those affected immediately to keep it from spreading. Plants that have become infected rarely go on the become the healthiest plant. Here are a few ways to deter damping off from occurring:

Keep It Clean

The number one way to prevent damping off is to keep the pathogens that cause damping off from reaching your garden. This is easier said than done when you’re trying to keep out something as small as a spore. Do your best to use sterile tools and keep a clean grow area. Using a grow tent can also be beneficial, creating a barrier that can help keep out pests that carry pathogens.

Heat It Up

Colder temperatures make a more suitable environment for the pathogens that cause damping off. Keep temperatures for germinating seeds and seedlings in the 70-80 degree range to decrease chances of damping off. To help with this I recommend using a seedling heat mat.

Air Circulation

Provide air circulation and start seedlings in a medium with good airflow to the root system. When germinating seeds in a dome, I often will take the lid off a couple of times a day and fan the grow medium. While multiple seeds per grow medium increases the chances of successful germination, it can also create less circulation, it’s a give and take. Using a garden fan will promote airflow and increase circulation.

Water From Below

Avoid too much moisture are the base of the seedling stem as this will increase the chances of damping off. To prevent this, water your plants from the bottom up. I like to use rapid rooter start plugs to germinate seeds and they have a nifty tray that holds water at the bottom, allowing the plugs to absorb water from the bottom.


Compared to soil gardening, hydroponic gardening is typically more sterile so damping off is typically less likely to occur. That said damping off can show up in hydroponic seeds and seedlings under the right conditions. It’s a frustrating occurrence that can cause setbacks so taking some extra precautions is well worth it.

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