Are coffee grounds beneficial for mint growth?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.When applied properly, coffee grounds deliver nutritional advantages for the mint. I use them in my herb garden after I brew coffee in the morning. Used coffee grounds lower the pH in soil, while also providing vital nitrogen for growth, which benefits the leaf uses of mint. Use minimally, or if you give your mint coffee grounds, you risk over-nutrition.
Preparation
- Spread wet grounds on tray to dry completely before use
- Mix with equal parts compost to balance acidity
- Never use flavored or decaffeinated grounds
Timing & Frequency
- Apply only during active growing season (spring-summer)
- Limit to once monthly applications
- Discontinue use 6 weeks before first frost
Soil Integration
- Work into top 2 inches of soil around drip line
- Combine with watering for gradual nutrient release
- Avoid direct contact with plant stems
Carefully observe how your mint responds to coffee grounds. Healthy plants show deeper green foliage within 10 days. Yellowing leaves indicate over-application, requiring immediate flushing. Stunted growth indicates a pH imbalance requiring garden lime adjustment. I check soil pH monthly during coffee ground additions.
Mix coffee grounds with complementary amendments. Combine coffee grounds with crushed eggshells to provide a balanced source of calcium. Mix coffee grounds with banana peels to add extra potassium. Use coffee grounds between straw mulch for slow breakdown. These mixtures provide complete nutrition, eliminating the need for chemical fertilizers.
Steer clear of the mistakes regularly made with coffee grounds. Never use thick layers of coffee grounds that will mold or repel water. Avoid winter applications when mint is dormant. Stop using coffee grounds when the soil pH is below 6.0. And, as always, use them in rotation with other organic fertilizers to provide a balanced nutrient supply.
Store coffee grounds properly between uses. If the grounds are dry, store them in airtight containers to prevent exposure to humidity. If you have too many grounds, consider freezing some for later use. Containers should be labeled with when they were collected. Like with food, use the oldest coffee grounds first. Good storage will also eliminate mold and nutrient loss.
Read the full article: How to Grow Mint: A Complete Beginner Guide
