Robusta coffee (Coffea canephora) is one of the most widely cultivated coffee types in Indonesia, especially in low to medium altitude areas. Known for its strong flavor, high caffeine content, and good resistance to plant diseases, Robusta coffee is a profitable commodity for both farmers and coffee entrepreneurs.
This guide provides a comprehensive step-by-step explanation of Robusta coffee cultivation — from seed selection to harvest — based on Good Agricultural Practices (GAP).
Understanding Robusta Coffee
Robusta coffee originates from West Africa and was introduced to Indonesia in the late 19th century as an alternative to Arabica coffee, which is more susceptible to coffee leaf rust (Hemileia vastatrix).
Characteristics of Robusta coffee:
- Optimal growth at 200–800 meters above sea level.
- Ideal temperature 24–30°C.
- Annual rainfall 2,000–3,000 mm.
- More resistant to pests and diseases than Arabica.
- Caffeine content 2–2.5%, higher than Arabica (1–1.5%).
Choosing the Right Location and Land
Ideal Location Criteria
To achieve optimal results, the Robusta coffee plantation should meet these conditions:
- Altitude: 200–800 meters above sea level.
- Soil type: Latosol, Andosol, or volcanic soil rich in organic matter.
- Soil pH: 5.5–6.5.
- Humidity: Stable throughout the year, with a dry period of 2–3 months to stimulate flowering.
Land Preparation
- Weed and shrub clearing: Reduces nutrient competition.
- Soil tilling: Loosen the soil to a depth of 30–50 cm.
- Terracing: For sloped land, to prevent erosion.
- Liming: If pH < 5.5, apply dolomite according to soil analysis recommendations.
Seed Selection and Nursery Preparation
Seed Source
Use certified high-yield varieties released by the government, such as:
- BP 42, BP 358, BP 409, and BP 534 known for productivity and disease resistance.
Nursery Technique
- Seed selection: Choose from perfectly ripe red cherries, wash clean, sun-dry for 1–2 days.
- Initial germination: Spread seeds on a sand bed, cover lightly, water regularly.
- Transfer to polybags: Once seedlings have 2 pairs of true leaves, move to polybags containing soil + compost (2:1).
- Maintenance: Water twice daily, provide 50–60% shade using shade nets.
Field Planting
Planting Season
Best done at the start of the rainy season (October–December) to ensure adequate water supply for adaptation.
Planting Distance
- Plant spacing 2.5 × 2.5 m or 3 × 3 m for optimal growth.
- On sloped land, adjust spacing to the terrace system.
Planting Steps
- Dig planting holes 60 × 60 × 60 cm.
- Mix the topsoil with 10–15 kg of well-decomposed manure.
- Plant seedlings upright, backfill with soil, and compact gently.
- Apply straw mulch to maintain soil moisture.
Plant Maintenance
Watering
During the dry season, water at least 2–3 times per week, especially for young plants.
Fertilization
- Year 1–2: 50–100 g Urea, 50 g TSP/SP-36, 50 g KCl per plant every 4 months.
- Year 3 onwards: Increase dosage according to soil analysis and plant age.
Pruning
- Formative pruning: Shape the main stem and primary branches.
- Production pruning: Remove old branches to stimulate new shoots.
- Sanitation pruning: Remove diseased or pest-infested branches.
Pest & Disease Control
- Main pests: Stem borer (Xylosandrus compactus), mealybugs, leaf caterpillars.
- Main diseases: Coffee leaf rust (Hemileia vastatrix), anthracnose, root fungus.
- Apply Integrated Pest Management (IPM), including field sanitation, routine pruning, and organic pesticide use when needed.
Harvesting Process
Signs of Ripe Cherries
- Bright, glossy red skin.
- Sweet-tasting fruit pulp.
Harvesting Technique
- Selective picking: Harvest only fully ripe cherries to maintain quality.
- Avoid picking green or overripe cherries as they affect flavor.
Harvest Season
Robusta coffee usually begins fruiting at 2.5–3 years old, with the main harvest once a year during the dry season.
Post-Harvest Processing
Wet Processing
- Pulping: Remove skin and pulp from the beans.
- Fermentation: 12–36 hours to remove mucilage.
- Washing: Clean remaining mucilage.
- Drying: Until moisture content reaches 12–13%.
Dry Processing
- Sun-dry cherries directly until fully dry, then hull.
Storage
- Store coffee beans in jute sacks in a cool, dry place to maintain quality.
Tips for Increasing Productivity
- Use certified high-yield varieties.
- Regular pruning for better light and air circulation.
- Conduct soil analysis every 2–3 years to adjust fertilization.
- Apply organic fertilizers to improve soil structure.
- Integrated pest control to keep plants healthy.
Conclusion
Robusta coffee cultivation requires proper planning and techniques, starting from seed selection, land preparation, planting, to harvesting and post-harvest handling. By applying Good Agricultural Practices, farmers can produce high-quality Robusta coffee with better market value both locally and internationally.
Success in Robusta cultivation lies in attention to detail, consistent maintenance, and adaptation to local environmental conditions.
