Seedlings Wilting? How to Control and Prevent Damping Off

Wilting seedlings got your down? Luckily, there are many ways to prevent damping off disease from taking over. Kevin Espiritu explains the causes behind this common disease and how you can prevent it.

How to Control and Prevent Damping Off


Damping off got you down? If you’re weeping with sorrow as your little green seedlings wilt and turn brown, you’re in the right place.

Alas, I’m pretty familiar with this situation. It mimics my day without coffee: I may start fine, but eventually, I shrivel up and collapse.

Luckily, there are many ways to prevent damping off disease from taking over. Here, you will find the information you need to keep your plants on track.

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What is Damping Off?

Close up of small green seedlings in a black tray in the sun. Several of the seedlings are brown and wilted.
Fungal diseases are typically the culprit to your seedlings damping off.

You’ve started your seeds with lots of tender loving care, watching over them like a hawk. Then, they suddenly drop faster than they appeared. What happened?

Usually, the culprit is fungal disease. They have fun-to-pronounce names like Pythium, Fusarium, Phytophthora, and Rhizoctonia. If you want to get technical, Fusarium and Rhizoctonia are fungi, and Pythium and Phytophthora are classified as oomycetes.

Sometimes the seeds never sprout. Other times, they do and quickly turn to mush soon after. It’s exceedingly frustrating to lose all your seedlings in one go.

These fungal spores often reside in the soil and can be transferred by contaminated garden tools, blown by the wind, or borne by insects. Once there, it doesn’t take a lot to destroy a bed of vulnerable young plants.

Symptoms of Damping Off Disease

Tray of tall seedlings in wet soil, some of which are brown and wilted.
Wilting and floppy stems are signs your seedlings have been exposed to disease.

It’s nearly impossible to avoid contaminated soil, as these fungal spores are everywhere. Potting soil and shared water make it easy for them to travel from seed to seed. The warmth of indoor conditions also encourages their development.

Seedlings affected by damping off often don’t make it past the soil level. Shriveling and darkening are common signs indicating a fungal issue.

Leaves appear waterlogged and mushy. When the disease is only present in the roots, plant growth is stunted, leading to wilting and death. Affected stems cause the plant to flop over. You may even see a white, cobweb-like substance in stricken areas.

While you’re accounting for your plants’ symptoms, ensure that you don’t have other culprits to blame for these issues, such as beetles and cutworms. The symptoms can look very similar, but the treatment and prevention are vastly different.

Damping Off Control and Prevention

Close up of small, clover seedlings in a black tray. Several seedlings are dry, yellowing and wilted.
There are several ways to help prevent your seedlings from damping off.

There is no cure for damping off once it has started, nor are there fungicides available. That’s why it’s all about control. You can prevent damping off by following a few simple techniques.

Soil Sterilization

Small shovel spooning dirt into a black plastic seed tray.
Always start with fresh potting soil when you sow your seeds.

There is some debate on the subject of sterilizing your growing medium. It is often recommended to prevent fungal spores from ruining your seedlings. Others believe these methods kill off beneficial microorganisms that would otherwise keep pathogens in check.

Whichever you choose, it is best to use new potting soil for your seeds. Perhaps even consider treated soils if you continuously encounter problems. If you are using your own soil and have problems with damping off, giving it a good roasting to sterilize it might be a good idea.


Close up of the back of a black, plastic seedling tray.
Make sure your seed trays have proper drainage.

While you’re figuring out whether to bake your soil or not, make sure you’ve chosen a well-draining growing medium. Waterlogged soil without drainage encourages fungal growth, increasing your risk of disease.

Tool Sterilization

Close up of a woman holding a small blue shovel, shoveling dirt into a small cardboard seed tray on a wood outdoor table.
Fungal disease and other harmful bacteria can be transferred through tools that haven’t been properly sanitized.

Gardening implements can carry nasty spores to your new seedlings if you’re not careful. To avoid transfer, ensure everything you use is clean prior to sowing. This may mean cleaning them yourself or simply using new containers.

Sow Smart

Close up of a hand sowing a seed into a seedling tray full of wet soil, and a small basket full of seeds next to it.
Sow seeds light and shallow and don’t overcrowd.

When sowing your seeds, keep it light and shallow. Too many seeds cause crowding, making evaporation more difficult. Sowing too deep will slow growth and reduce air circulation, giving pathogens more time to strangle their hosts.


Seedling tray with a clear plastic lid that has condensation inside of it, sitting on top of a heating mat.
Heating pads are good for maintaining a consistent temperature for your seedlings.

For indoor sowing, consider using a heating pad to warm the soil to around 70°F (21°C). For outdoor sowing, check the temperature of the soil prior to planting. Wait until the earth has reached optimal warmth for the plants you choose.


Close up of a small black tray with tall, delicate seedlings sprouting up, sitting in front of a sunny window.
New seeds will need about 6 hours of light per day.

Grow lights are recommended to avoid damping off indoors. Sufficient light will help the new plants grow vigorously, building quick resistance to disease. A window is often not enough, especially in winter. Aim for at least 6 hours of light per day, or more when using grow lights.


Close up of tall seedlings with a woman watering them with a glass watering jar in the background.
Watering from the bottom up is ideal when establishing roots.

Consider using clean, lukewarm water on your seedlings. Water from underneath rather than overhead, keeping the leaves and top soil layer dry.

For outdoor gardens, water before noon to allow ample time for evaporation. The damper, cooler evening temperatures give fungal spores a chance to spread if there’s plenty of moisture around.


Close up of a hand pinching off small seedlings in a process of thinning out.
Once your seeds sprout, thin them out so they can get proper airflow.

When sowing several seeds in one hole or sprinkling seeds close together, your sprouting seedlings need thinning. Overcrowding restricts airflow and traps moisture, increasing your risk of fungal disease.

Thin your seedlings, keeping the strongest ones growing, to improve air circulation and evaporation.

Final Thoughts

To avoid the frustration of losing plants to damping off, try these suggestions. Your young seedlings will thank you with strong growth later in the season.

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