Turning Coffee Husks into Sustainable Fertilizer at HuyEco Farm

Turning Coffee Waste into Sustainable Fertilizer

At the beginning of 2025, we are wrapping up the coffee harvest at Midori Farm. This year, in addition to tending to our own coffee trees, I decided to purchase coffee cherries from neighboring farms.

The goal is twofold:
✅ Support local farmers in transitioning to low-chemical or chemical-free cultivation.
✅ Supplement supply for our partner cafés while improving overall coffee quality.

But what about waste management? Instead of discarding coffee husks, I’m turning them into organic fertilizer, helping to close the loop in sustainable coffee farming.

Composting Process – How We Transform Coffee Husks

To kickstart composting, I ordered:

🚛 2 truckloads (~10m³) of fresh coffee husks
🌿 20 sacks of fully decomposed dry cow manure
🦠 Trichoderma fungi (spore density: 10⁹) for compost activation

Step-by-Step Method:

1️⃣ Prepare the compost pile – Layer husks and manure evenly.
2️⃣ Hydrate & mix –

• Dry cow manure absorbs more water, requiring thorough soaking.
• Fresh coffee husks retain moisture, so water is applied gently.
  3️⃣ Introduce microbes – Mix 1 kg of Trichoderma fungi into 300 liters of water and spray over the compost pile.
  4️⃣ Cover with a tarp – Leave the bottom exposed for air circulation, as Trichoderma is an aerobic fungus.

📅 Next Steps:
✅ In early February, I’ll turn the compost pile to aerate and speed up decomposition.
✅ After repeating the process a few times, the compost should be ready for application within a month.

Challenges & Scaling Up

This batch is just an experiment—let’s look at the numbers:

• Ratio: 4m³ of coffee husks ≈ 1 ton of compost
• Target: 1,000 coffee trees
• Available Compost: 10m³ of husks + 20 sacks of manure ≈ 2.5 tons
• Ideal annual need: 100kg of compost per tree
• Reality: This batch only covers 100 trees for one cycle 😆

🔥 Scaling up requires:
➡ 100m³ of coffee husks
➡ Unlimited cow manure (or expanded compost alternatives)

Cost Estimates

Here’s the estimated budget breakdown for scaling compost production:

This cost estimate provides a clearer picture of what’s needed to scale sustainable composting at HuyEco Farm.

Final Thoughts & Future Steps

✅ This experiment sets the foundation for a larger-scale composting system at HuyEco.
✅ Coffee husks are an untapped resource—turning them into fertilizer aligns with our goal of closed-loop farming.
✅ The next phase: Expanding production, refining cost efficiency, and integrating compost tea applications.

Sustainability is about continuous learning and adaptation—this project brings us one step closer to self-sufficient farming at HuyEco. 🚀