Soil pH determines nutrient availability more than fertilizer quantity

You can dump unlimited nitrogen on a lawn with pH 4.5 and the grass still starves — the nutrients are chemically locked in acidic soil. Most vegetables thrive at pH 6.0-7.0. Test soil pH annually with a $10 kit. Amend with lime to raise pH (takes 3-6 months) or sulfur to lower it. Per most state extension services, pH correction is the single highest-ROI action for any garden.