Mold on Peat Pots

Peat pots protect seedling roots during transplanting.

Organic matter contains bacteria and fungus that breaks it down to form peat and humus. Given the right conditions, some of those organisms can spring to life. Peat pots, composed of organic peat, are not immune.

Top

White mold growing on the top surface of the pot and dirt surface may be due to non-sterile soil or to overhead watering. Seeds do not need nitrogen to germinate, so use only sterile, soil-less medium to start seeds. Allow the peat pot to dry and trim the moldy edges.

Sides

Green or brown mold climbing up the sides of the pot results from the pot sitting in water. Allow the pot to dry before watering again and empty the drainage tray after 15 to 20 minutes. If there are no holes in the bottom of pots, make holes with a sharp pencil so excess water can drain.

Acid-Loving Mold

Peat moss is more acidic than garden soil and acidic mulches promote the growth of fungus molds. Controlling bottom heat and avoiding standing water, both of which encourage fungus development, will help keep peat pots from sprouting mold.

References

• Floridata: Start Your Own Pepper and Tomato Plants
• Ohio State University Extension: Control of Nuisance and Detrimental Molds (Fungi) in Mulches and Composts; Harry A. J. Hoitink