damping-off seedling tray

Anyone who has started seeds has or will experience damping-off.

You planted your seeds.  You nurtured them and were soon rewarded with the appearance of the tiny sprouts emerging from the soil.  You watered them and watched each day as they grew taller and began to spread their leaves.  Then, you watched in horror as they lay over in mass and shriveled up dead.

What happened?

More than likely, your plants suffered from damping-off.  Damping-off is caused by several fungi that exist everywhere.  The three main culprits are Pythium, Rhizoctonia, and Phytophthora. 

damping-off seedling

If you examine your seedlings carefully, you may notice a small swelling or blackened area on the stem just where it emerges from the soil.  Sudden wilting is a classic sign of damping-off.  The fungi may also attack the seeds, causing them to rot before they germinate or even attack the seedlings before they have a chance to emerge from the soil. 


The fungi associated with damping-off need the right conditions to proliferate, and like cool wet conditions in the soil.  Overwatering or potting soil that doesn’t drain well can lead to a sudden and disastrous attack of damping-off.  Entire seed trays can be lost in a day.

There are some things you can do to help prevent damping off.


Use a good seed starting mix.  Your seed starting mix should be healthy and alive, not sterile as many seed starting mixes advertise.  Sterile media doesn’t contain the bacteria and other organisms that can help keep the fungi in check.  See our article on seed starting for more information on seed starting mixes.

Do Keep everything else as clean as possible.  If you are reusing pots or seed starting trays, wash them and sterilize them with a bleach solution to make sure you aren’t bringing any remaining pathogens to your new seedlings.

Make sure that your pots or trays drain properly.  Soil that stays to wet is an invitation to damping-off and other diseases and pests. 

Temperature can be a factor.  Your seedlings need to stay at the proper temperature.  Check the recommendations on the seed packaging for the minimum soil temperature for your seeds.

After you plant your seeds, add some whole cornmeal to the surface of the planting media. Adding some rock phosphate to the top of the soil may also help.

Air Circulation

damping-off healthy seedlings

Your planting trays or pots need air circulation.  Don’t put your trays or pots in areas where the air doesn’t move.  Lack of air movement can aggravate the situation. 

If you do notice damping-off in your trays or pots, get those plants out of the area immediately. 

We have all experienced damping off at one time or another.  It is almost guaranteed that you will see damping-off on occasion.  Don’t be discouraged.  Follow the recommendations above and try again.

Links and Resources

For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening.

If you found the information here helpful, you might also find these articles on our website of interest.

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If you have more specific questions or problems, you can contact us using the contact form on our website. You can also post your question to our community forum at this page; West Texas Organic Gardening Community Forum.

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