Mold on your seeds is often a sign that your growing environment is too damp and lacks sufficient ventilation. Here's a breakdown of the common causes and how to address them:
1. Overwatering:
- The Problem: Excess water creates a humid environment ideal for fungal growth. Seeds and young seedlings are particularly susceptible because their roots can rot in overly saturated soil.
- The Solution:
- Ensure your seed starting mix is well-draining.
- Water only when the top of the soil feels dry to the touch.
- Avoid overwatering by using a spray bottle or bottom watering (placing the seed tray in a shallow dish of water and allowing the soil to absorb moisture from the bottom).
2. Poor Ventilation:
- The Problem: Stagnant air allows moisture to accumulate, fostering mold growth.
- The Solution:
- Provide adequate ventilation by using a small fan to circulate air around your seedlings. Make sure the airflow is gentle.
- Avoid overcrowding seedlings, which can restrict airflow.
- If using a humidity dome, remove it regularly to allow for air exchange.
3. Contaminated Seed Starting Mix:
- The Problem: The seed starting mix itself might contain mold spores or other pathogens.
- The Solution:
- Use a sterile seed starting mix specifically designed for seedlings. Avoid using garden soil, as it can harbor pests and diseases.
- Consider sterilizing your own seed starting mix by baking it in the oven (follow safe sterilization guidelines).
4. Insufficient Light:
- The Problem: Lack of light can weaken seedlings, making them more vulnerable to mold and disease. It also slows down water absorption.
- The Solution:
- Provide adequate light by using grow lights or placing seedlings in a sunny location.
- Ensure seedlings receive at least 12-16 hours of light per day.
5. High Humidity:
- The Problem: Although some humidity is good for germination, too much encourages mold growth.
- The Solution:
- Monitor humidity levels. Aim for around 50-60% after germination.
- Remove humidity domes or covers once seeds have sprouted.
- Improve ventilation to reduce humidity.
What to do if you see Mold:
- Remove affected seedlings: Carefully remove any seedlings with visible mold to prevent it from spreading.
- Improve ventilation: Increase airflow around the remaining seedlings.
- Reduce watering: Allow the soil to dry out slightly.
- Consider a fungicide: As a last resort, you can use a fungicide specifically formulated for seedlings. Be sure to follow the instructions carefully.
In short, mold on seeds generally indicates an environment that is too wet and lacks proper airflow. Adjusting your watering habits, improving ventilation, and ensuring a sterile growing medium are crucial steps in preventing mold and promoting healthy seedling growth.
