How to Choose the Best Site for Arabica Coffee in PNG

Acknowledgment:
This guide is adapted from the Coffee Industry Corporation (CIC) PNG Coffee Handbook 2016. We have simplified the content for easier understanding by farmers.

Growing coffee in the right place is one of the most important steps for a successful harvest. The land you choose affects how well your coffee grows, how much work you need to do, and how much money you can earn.

1. Why Choosing the Right Site Matters

• Coffee grows best in certain types of soil, climate, and slope.
• Choosing the wrong site can cause:
  • Low yields (less coffee produced)
  • Extra costs for fertilizers, pest control, and soil improvement
  • Plants that don’t survive long-term

2. Seven Key Things to Check Before Planting

1. Soil Drainage & Depth (How deep and well water drains in the soil)
2. Altitude & Temperature (Height above sea level and warmth)
3. Rainfall (How much rain the area receives and how it is spread through the year)
4. Erosion Risk (How likely soil is to wash away on slopes or heavy rain)
5. Soil Fertility (Nutrients in the soil)
6. Accessibility (How easy it is to reach the farm)
7. Current Land Use (What is already growing or being used on the land)

 3. Explaining Each Feature

3.1 Soil Drainage & Depth

• Coffee roots need well-drained soil to grow.
• Shallow or waterlogged soil means poor root growth and weak plants.
• Guidelines for farmers:
  • Best: Soil > 1.2 meters deep and drains well
  • Moderate: 0.5 – 1.2 meters deep, minor drainage fixes may help
  • Marginal: 0.2 – 0.5 meters deep, requires extra drainage (only for farms with high inputs)
  • Not suitable: < 0.2 meters or water cannot drain

Tip: Check for rocks, hard layers, or areas that stay wet for long periods.

3.2 Altitude & Temperature

• Coffee prefers cool, frost-free climates.
• Use altitude (height above sea level) to estimate temperature:
  • Ideal: 1300 – 1700 meters
  • Moderate: 1100 – 1299 m or 1700 – 1900 m
  • Marginal: 600 – 1099 m or 1900 – 2500 m
  • Not suitable: Below 600 m or above 2500 m

Tip: Shade trees can help protect coffee in areas slightly too hot or cold, but may reduce yield.

3.3 Rainfall

• Coffee needs water to grow, but too much rain causes disease.
• Best rainfall: 2000 – 3000 mm per year
• Marginal: 1500 – 1999 mm or 3000 – 4000 mm
• Not suitable: <1500 mm or >4000 mm

Tip: Coffee flowers best when a dry period is followed by rain.

3.4 Erosion Risk

• Slopes and heavy rain can wash away topsoil and nutrients.
• Steep slopes are harder for high-input plantations to manage.
• Guideline: Avoid slopes over 60% for plantations. Smallholders can manage steeper slopes carefully.

3.5 Soil Fertility

• Coffee needs nutrients like nitrogen, potassium, magnesium, phosphorus, and the right soil acidity (pH).
• Poor soils can still grow coffee if you add fertilizers.

3.6 Accessibility

• High-input farms need roads for vehicles to bring fertilizers, fungicides, and tools.
• Smallholder farms can manage with walking paths or motorcycles.

3.7 Current Land Use

• What is the land currently used for?
  • Gardens, forests, or pastures may need clearing.
• Consider the cost, effort, and local land ownership rules.

4. Understanding Suitability Classes

We rate each factor (soil depth, altitude, rainfall, etc.) to decide how suitable a site is:

Overall Suitability: Combine all the ratings to classify the whole site:

Tip: We can add letters to show the main limitation:

• a = altitude
• d = drainage
• r = rainfall
• e = erosion
• f = soil fertility
• c = accessibility
• u = current land use

Example: S2ae → Moderately suitable, limited by altitude and erosion.

5. Final Advice for Farmers

1. Avoid N sites.
2. S3 sites are okay for smallholders but not recommended for plantations.
3. S1 or S2 sites are safe for all types of coffee farms.
4. Always check all factors together, not just one.