Soil pH Explained: Test, Adjust & Match Plants Perfectly

Soil pH controls nutrient availability. Get it wrong, and plants starve—even in rich soil. Here's how to measure, modify, and match.

The Scale

• 1–6.9: Acidic
• 7: Neutral
• 7.1–14: Alkaline
• Sweet spot for most plants: 6.0–7.0

Why It Matters

• Nitrogen available >5.5
• Phosphorus available 6–7
• Micronutrients (Fe, Mn, Zn) lock up in high pH
• Wrong pH = deficiency symptoms, disease susceptibility

Test It

• Kit: soil sample + solution + color chart = pH reading
• For large areas: combine multiple samples
• Hydrangea shortcut: blue flowers = acidic; pink = alkaline

Raise pH (More Alkaline)

• Add lime: agricultural limestone (slow), burnt/hydrated lime (fast)
• Finer particles = faster
• Allow 2–3 months

Lower pH (More Acidic)

• Aluminum sulfate: fast, risk of over-application
• Elemental sulfur: slower (bacteria-dependent), safer, longer-lasting
• Months to work—plan ahead

Test annually. Adjust gradually. Match plants to pH, not pH to plants. Your garden will thank you.