Soil pH is one of the most overlooked factors in home gardening, yet it controls how well plants can absorb nutrients. Most vegetables thrive in slightly acidic to neutral soil (pH 6.0-7.0).
What Is Soil pH?
pH is a measure of hydrogen ion concentration in soil, on a scale from 0 (highly acidic) to 14 (highly alkaline), with 7.0 being neutral. Small changes represent large differences.
Why It Matters
Nutrients like nitrogen, phosphorus, and potassium are most available in the 6.0-7.0 range. Outside this window, nutrients become locked up in the soil even if you fertilize heavily.
Testing Your Soil
Buy an inexpensive pH test kit from a garden center or send a sample to your local cooperative extension service. Test in multiple spots - pH can vary significantly even within a small garden.
Fixing Acidic Soil (Below 6.0)
Add agricultural lime (calcium carbonate). Work it into the top 6 inches of soil. Results take 2-3 months, so amend in fall for spring planting.
Fixing Alkaline Soil (Above 7.5)
Add elemental sulfur, which soil bacteria convert to sulfuric acid over time. Acidifying fertilizers and peat moss also help lower pH gradually.
Plants That Prefer Acidic Soil
Blueberries (pH 4.5-5.5), azaleas, and potatoes prefer more acidic conditions. Maintain a separate amended bed for these crops.