How to Use Eggshells for Plant Fertilizer

Use discarded eggshells as plant fertilizer.

Avoid spending money on store-bought plant fertilizer and use your own garbage. Discarded eggshells are often used as a plant fertilizer. This is because eggshells contain calcium. According to the Santarosa County Extension at the University of Florida, the alkaline calcium raises, or neutralizes, the pH level of overly acidic soil, in turn promoting early growth in plants. Most plants prefer slightly acidic soil with a pH between 5.8 and 7.0. Plants that thrive in soil with this pH are asparagus, onions and strawberries. A study conducted by student researchers at PlantingScience.org revealed that red clover plants fertilized with eggshells grew an average of more than 10 mm larger than plants without eggshells. Making eggshell fertilizer is inexpensive and eco-friendly, since the process reuses material to promote plant growth.

Things You'll Need

• Eggshells
• Towel
• Blender

Instructions

1. Collect several eggshells and rinse off any egg residue. Each plant will require between four and five eggshells. Set the shells on a towel to dry. Make sure the eggshells are completely dried out before proceeding.

2. Place the eggshells in a blender. Depending on the size of the plant area to be fertilized, the number of eggshells will vary.

3. Hit the "Pulse" button on the blender to turn the blade. Keep hitting "Pulse" until the eggshells become powdery.

4. Dust the powder over the plant soil. Water the soil regularly, keeping it moist every day.

Tips & Warnings

• Mix a small amount of dried coffee grounds with the crushed eggshells, then sprinkle on the soil. Coffee grounds contain nitrogen, magnesium and potassium and raise the acidity in the soil.

References

• Santarosa County Extension at the University of Florida: Nutrient Deficiency
• Planting Science: The Effects of Coffee and Eggshells as Fertilizer for Red Clover and Barley Seeds
• Master Gardeners of Hamilton County, TN: Homemade Fertilizers
• Clemson University: Lowering Soil pH
• The Garden Helper: Recommended Soil pH for Growing Garden Fruits and Vegetables

Resources

• Earthbox Forum: Fertilize with Eggshells?