Q: I planted a variety of seeds in trays this spring, preparing for potting and outdoor planting as temperatures rise. However, I've noticed green mold appearing on the soil in several trays. What's causing this, and should I worry?
A: Starting plants from seeds is fulfilling, but issues like mold can occur. This mold typically arises from excess moisture and humidity, notes a gardening expert.
No need to panic; the mold likely won't harm the seedlings themselves. However, it signals that the growing environment may not be ideal for strong plant development, so it's wise to take action.
A gardening journalist for over 50 years, the expert frequently addresses readers' inquiries in a well-known magazine, and has authored several books and given numerous talks on horticulture.
High moisture and humidity lead to mold growth
Preventing Green Mold on Seedlings
Avoiding mold on seedling trays can be challenging, as fungal spores are everywhere and thrive under conditions ideal for seed germination.
Yet, you can take steps to minimize risks and promote a healthier environment for your seedlings.
- Always opt for clean pots and fresh potting soil, like Miracle-Gro's Seed Starting Potting Mix, available on Amazon. 'Avoid reusing old soil, and seal bags tightly when not in use,' the expert advises.
- Overwatering is a frequent mistake when planting seeds. Water seedlings from the bottom, if possible. 'This keeps the compost surface drier, making it less attractive to mold.'
- After sowing seeds, a thorough soaking may eliminate the need for more water until germination, provided the pots remain covered in warm, shaded conditions.
- Ensure seedlings aren't overcrowded and that air circulation is sufficient. Warm, stagnant air increases humidity, creating a perfect environment for mold growth.
- Lastly, the expert recommends pricking out seedlings to transplant once they are big enough to handle. This allows for fresh soil and spacing, improving airflow and reducing humidity.
Transplant your seedlings promptly for ample growing space
What to Do About White Mold on Seedlings?
If you notice white mold along with wilting or decaying seedlings, they may be suffering from the common disease known as 'damping off.' This condition stems from inadequate airflow and high humidity, so implementing the aforementioned strategies can help prevent it.
Using tap water instead of rainwater for your seedlings is also advisable, as noted by a reputable gardening society. If you opt for rainwater, ensure it's covered to reduce the risk of contamination.
Should you observe damping off, immediately transplant any healthy seedlings into a new tray with fresh soil.
Ultimately, it's about fostering an optimal environment for your seedlings. By following these guidelines, you'll significantly increase your chances of growing healthy vegetables and vibrant flowers this summer.
