What’s Wrong with My Seedlings?

When gardening, it’s an unavoidable fact that you will have successes as well as failures. Failures can be caused by an outside force you have no control over (cat digging up your seedlings, a tray of tiny green shoots getting knocked off the table by accident, etc.), but it can also be caused by things you do have control over. Overwatering, under watering, not enough light, and more. These mistakes are very common, and not something to feel bad about!

1. Seeds fail to germinate?

Possible Causes

• Temperature of the soil is too hot or too cold. Most seeds like a soil temperature of around 65°-75°F. In general, 

• the warmer the temperature, the faster the seed will germinate. Please note that even if the air feels warm, the soil may still be chilly. We often recommend a bottom heat source. 
• Seeds rotting in the soil means it was too wet. Your soil should be moist, but not soaked.
• Planting depth of the seeds – plant too deeply, and germinating seeds have a hard time reaching the surface or light is unable to reach the seed. Plant too shallow, and too much light can damage the seed. Most seed packets will instruct you on how deep to plant your seed!
• Growing medium was allowed to dry out. Your soil should remain moistened but not drenched, and not bone dry.
• ‘Damping off’ disease, which can affect the seeds before they germinate. Damping off occurs when a pathogen that thrives on too-wet conditions is able to grow and kill the seeds before they can emerge.
• Remember - Pinetree stands behind its products! We will always work with you if you have concerns about germination of seeds you have purchased from us. 

2. Seedlings fall over or start to decay at soil level

 

 

This is a sign of damping-off disease (fungus organisms that attack seeds and young seedlings, ultimately killing them). Some causes of damping-off are:

• Cold, wet soil
• Poor soil drainage
• Poor air circulation
• Unsterilized soil mix, or reusing soil from previous seed starting
• Dirty growing containers
• Stress from low light

 

 

 

 

3. Leaves start to curl under, growth appears stunted or dwarfed

Possible Causes

• Too much light. Seedlings need a ‘rest’ period, which is why it is suggested to only provide 14-16 hours of light.
• Over or under fertilization. Too little nutrients can stunt growth, too much nutrition can damage the roots and prevent the seedling from taking in water.
• Low temperatures. Most seeds like a soil temperature of around 65°-75°.
• Excessive moisture and overwatering. If the soil remains consistently wet, it can rot the roots and prevent the seed from taking in water. It may look like your seed needs water, but in actuality, it needs anything but! Make sure to test the moisture of your soil by feeling with your fingers. Soil should be moist but not soaked.

 

 

 

 

4. Seedlings have pale, discolored leaves; or leggy, spindly growth

Possible Causes

• Insufficient lighting, or light source too far from your seedlings
• Fertilizer burn from adding too much fertilizer, which can damage the plant's root system
• Excessive watering
• Nutrient deficiency – check the growing medium you are using to find out if nutrients are supplied in the mix. Some have tiny amounts to just get seedlings going, which means you then have to supply the rest until planted out in the garden.
• Overcrowding of seedlings. Be sure to thin your seedlings to prevent this.
• Temperatures too high. Most seeds like a soil temperature of around 65°-75°.

 

 

 

5. When transplanting, you see poorly developed root systems

Possible Causes

• Poor drainage
• Low soil fertility
• Damage from fertilizer salts, a.k.a. ‘fertilizer burn’, by adding too much fertilizer
• Low soil temperatures. Most seeds like a soil temperature of around 65°-75°.
• Compacted soil (lack of air space in growing medium), which can arise from overwatering and poor drainage.

 

 

 

 

 

 

6. Moss or mold is growing on your medium

Possible Causes

• Lack of air circulation. Set a fan up to move air around your plants
• Excessive moisture. If the soil remains consistently wet, it can rot the roots and prevent the seed from taking in water. It may look like your seed needs water, but in actuality, it needs anything but! Make sure to test the moisture of your soil by feeling with your fingers. Soil should be moist but not soaked.

 

 

 

 

 

 

 

7. Try playing some tunes for your seedlings!

We know that there is no proof to back this up, but have you thought about playing some of Pinetree's certified Spotify playlists to help the seedlings grow? 

 

 

 

 

Here’s a short message of encouragement from our master gardener, Jaci:

“As a gardener, I know how discouraging it can be when some seedlings fail or don’t look perfect. Try not to dwell on it too long; just take the opportunity to gain some knowledge on the possible underlying causes so you can be successful in the seasons ahead. I have been gardening for nearly 20 years, and each year still brings new learning experiences for me.”

 

Some quick tips for making sure your seedlings flourish!

• Once your seedlings have 2-3 sets of leaves, the most important thing to do at this point is to supplement them with nutrients! Most seed starting mixes have very little nutrition if any at all. We suggest using ¼ to ½ strength liquid fish/seaweed fertilizer every other watering for your seedlings to be at their happiest!
• Using a soilless seed starting mix to start seeds is very important. Soilless seed starting mix is light, fluffy, and perfect for your seedlings to grow strong, sturdy roots! Garden soil or potting soil is often far too heavy and lacking in drainage, making it hard on the delicate root systems of the young seedlings.

What are your favorite tips and tricks for seed starting?