Soil Testing Before Winter: Why and How

By James Mitchell · October 6, 2026

Why Test in Fall?

Fall soil testing gives a spring head start. Amendments like lime and phosphorus take months to break down. Testing now means corrections are ready when plants need them.

What to Test

pH: Most vegetables prefer 6.0-7.0; blueberries need 4.5-5.5
N-P-K: Nitrogen, phosphorus, potassium levels
Organic matter: Aim for 3-5% in garden soil
Calcium/magnesium: Critical for tomatoes and peppers

Sampling Method

Take 5-10 subsamples from different spots at 6-8 inches deep. Mix in a clean bucket and send a cup to an extension lab or use a home kit.

Interpreting Results

Low pH: add lime in fall (3-6 months to work). Low phosphorus: add rock phosphate or bone meal now. Potassium: correct with greensand or wood ash.

Cost and Turnaround

Extension lab tests cost $10-25 with 1-2 week turnaround. Home kits give immediate results but are less precise.