Are coffee grounds good for beans?
Written by
Tina Carter
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Coffee grounds benefit bean plants. When used properly, they are a source of nitrogen and improve soil texture. As an organic gardener, I have recycled thousands of coffee grounds into bean beds. Still, when misused, they can do more damage than good. They can create acidity problems if fresh, but when composted and used, they provide a slow-release feed that promotes robust growth without the need for chemical fertilizers.
Composting Process
- Mix grounds 1:3 with brown materials like leaves
- Maintain 60°C (140°F) for pathogen elimination
- Turn pile weekly for 6 months until crumbly
Soil Integration
- Work composted grounds 10-15 cm deep at planting
- Top-dress established plants avoiding stem contact
- Combine with crushed eggshells to balance acidity
Balance your soil chemistry then. My beans prefer a neutral pH range of 6.5-7.0. Still, excessive grounds can lower the pH and create problems with aluminum toxicity. I have my soil consulted monthly while the growing season persists. On acidic soils, you could also apply lime at 100g/m² to counteract the effects of the coffee as much as possible, but still maintain its benefits.
Apply at key growth stages for maximum impact. Mix composted grounds into the soil before planting bush beans, and side-dress pole varieties when flowering begins. Do not apply when pods are forming, as excess nitrogen can reduce yields at this stage. I like to time applications to coincide with the lunar cycles.
Identify signs of improper usage: Leaves yellow due to acidity. Stretched growth caused by caffeine residue. Flush soil with 10 liters of water per plant, then treat with dosing of dolomite lime to replace the pH balance. I usually keep ground applications 10% or less.
Add to your blend with other amendments to balance out your nutrient profile. Mix with wood ash for a potassium boost. Blend with bone meal to increase your phosphorus levels. I blend my grounds in a custom mix. Mine is a four-part mixture of composted coffee grounds, one part kelp meal, and one part rock phosphate. This is a lovely mix for a slow-release blend throughout the year!
Read the full article: When to Plant Beans for a Bountiful Harvest
