Damping Off

Lettuce Damping Off: A Guide for Young Gardeners

Introduction

Have you ever planted lettuce seeds and watched them sprout into healthy seedlings, only to see them suddenly wilt and die? This is likely due to a common disease called damping off. Damping off is caused by harmful microbes that thrive in unhealthy growing conditions. But don’t worry, it’s preventable! Read on to learn everything you need to know about damping off in lettuce and how to protect your seedlings.

Symptoms of Lettuce Damping Off

Lettuce seedlings suffering from damping off will show the following symptoms:

• Brown or white moldy patches on the stem
• Weakening and falling over of the stem
• Mold growing on the soil surface
• Black or brown roots when you pull up a dead seedling
• Infected seeds that fail to germinate

Causes of Lettuce Damping Off

Several types of microbes can cause damping off in lettuce, including Rhizoctonia solani, Pythium species, Sclerotinia species, and Thielaviopsis basicola. These microbes thrive in damp, humid conditions. The most common cause of damping off is overwatering, which makes seedlings more susceptible to stem and root infections.

Preventing Lettuce Damping Off

The best way to prevent damping off is to provide your lettuce seedlings with a healthy growing environment:

• Use a well-drained seed starting mix: This will help prevent the soil from staying too wet.
• Avoid overwatering: Water seedlings only when the surface of the soil is slightly dry to the touch.
• Provide good ventilation: Remove any covers from seed trays to allow air to circulate.
• Don’t reuse soil or seed starting mix: Damping off pathogens can survive in soil, so it’s important to discard any infected soil.
• Avoid planting in cold, wet soil: Lettuce seedlings are more vulnerable to damping off in these conditions.

Treating Lettuce Damping Off

Once a seedling is infected with damping off, it is unlikely to survive. However, you can correct the problems in the growing conditions and try again with new seedlings:

• Remove infected seedlings: Pull up and discard any seedlings that show symptoms of damping off.
• Improve drainage: Make sure the soil is well-drained by adding sand or perlite.
• Reduce humidity: Increase air circulation by providing ventilation.
• Use a fungicide: If damping off persists, you can apply a fungicide specifically formulated for damping off.

Additional Tips for Healthy Lettuce Seedlings

In addition to preventing damping off, there are a few other things you can do to ensure your lettuce seedlings thrive:

• Start seeds indoors: This will give your seedlings a head start and protect them from harsh weather conditions.
• Provide plenty of light: Lettuce seedlings need at least 6 hours of sunlight per day.
• Fertilize regularly: Fertilize seedlings every few weeks with a balanced fertilizer.
• Harden off seedlings: Before transplanting seedlings outdoors, gradually expose them to outdoor conditions for a few hours each day.

By following these tips, you can prevent damping off and grow healthy, vibrant lettuce seedlings that will thrive in your garden.