Soil pH for vegetables: what it is and how to test it
Last reviewed September 2026 · written from public-domain USDA/NOAA data and Cooperative Extension references — see how we source data
Soil pH controls how available nutrients already in the soil are to plant roots. Get it far enough out of range and it does not matter how rich the soil is — key nutrients lock up chemically and the plant cannot use them.
Why it matters
Most vegetables grow best between pH 6.0 and 7.0 — slightly acidic to neutral. Below about 5.5, phosphorus and several micronutrients become less available; above about 7.5, iron and manganese do. Blueberries and a few other crops are the exception, wanting more acidic soil still.
Testing it
A home pH kit or meter gives a rough, quick reading, useful for a sanity check. A lab test through a county Cooperative Extension office costs a few dollars, gives pH alongside actual nutrient levels, and is worth doing every two to three years or when starting a new bed.
Raising pH (too acidic)
Garden lime is the standard fix, applied in fall so it has months to react before spring planting. How much to apply depends on both your current pH and your soil type (clay needs more than sandy soil to move the same amount) — exactly what a lab test tells you.
Lowering pH (too alkaline)
Elemental sulfur, or working in acidic organic matter like pine needles or peat, brings pH down — slower than raising it, and worth retesting after a season rather than repeatedly applying more.