Reading Soil pH in Small Mixed Fields

Why pH matters

Soil pH tells you how acidic or alkaline your soil is. It affects how well crops can absorb nutrients. Wrong pH means your plants can't use the fertilizer you apply, even if the soil has plenty of nutrients.

Most crops grow best in slightly acidic to neutral soil (pH 6.0–7.0). If your pH is too low (acidic) or too high (alkaline), crops struggle.

What the numbers mean

• Below 6.0: Too acidic. Crops like maize, cassava, and vegetables may show poor growth.
• 6.0–7.0: Good range for most crops.
• Above 7.5: Too alkaline. Nutrient lockup becomes a problem, especially for iron and zinc.

How to test pH

Option 1: Soil test kit (cheap and quick)

You can buy a simple pH test kit at agro-dealer shops or online. It usually includes color strips or a small meter.

Steps:

1. Take a small soil sample from 6-8 inches deep (mix from 3-5 spots in the field)
2. Remove stones and debris
3. Follow the kit instructions (usually mix soil with water and dip the strip)
4. Match the color to the chart provided

Option 2: Lab test (more accurate)

If you're applying lime or sulfur to adjust pH, get a lab test first. It's more accurate and often includes other nutrient readings.

See the "Basic Soil Sampling" guide in this Knowledge Hub for how to collect samples properly.

Fixing pH problems

If pH is too low (acidic, below 6.0)

Solution: Apply lime (agricultural lime or calcium carbonate).

• How much: Typically 1-2 tons per hectare, but check lab recommendations
• When: Apply 2-3 months before planting so lime has time to react with soil
• How: Spread evenly and mix into topsoil (don't just dump in one spot)

If pH is too high (alkaline, above 7.5)

Solution: Apply sulfur or organic matter (compost, manure).

• Sulfur: Apply 50-100 kg per hectare (follow extension advice)
• Organic matter: Add compost or well-rotted manure (this works slowly but is safer)
• Timing: Apply several weeks before planting

Tips for mixed cropping

If you grow multiple crops in the same field:

• Test pH in different sections (one corner may be different from another)
• Focus lime or sulfur applications on problem areas rather than the whole field
• Choose crops that tolerate your current pH until you can adjust it

Quick checklist

• ✓ Test pH once per season or if crops are struggling
• ✓ Aim for pH 6.0–7.0 for most crops
• ✓ Use lime to raise pH (if too acidic)
• ✓ Use sulfur or compost to lower pH (if too alkaline)
• ✓ Apply amendments 2-3 months before planting for best results

Next steps

Log your pH readings in the Torade app's soil tool. Track changes over time and note which amendments worked. This helps you plan better for future seasons.