Soil pH affects nutrient availability to plants. Most garden plants prefer a slightly acidic pH range of 6.2 to 6.8. If the soil pH is too acidic or alkaline, nutrients may not be readily accessible to plants. Gardeners can adjust soil pH by adding amendments like agricultural lime to raise pH in acidic soil or elemental sulfur to lower pH in alkaline soil. Regular soil testing allows gardeners to monitor and stabilize pH levels for optimal plant nutrition.