A wide array of garden vegetable crops grow very well in slightly acidic soil. Plants are adaptable, being able to prosper in soil pH varying slightly from optimal. If the planting bed falls within a pH range of slightly acidic to neutral, no soil pH amending is necessary. For more ease, choose crops that cope with the soil pH extant in the planting beds.
Most vegetable crops assimilate and grow well in acidic soil, sometimes referred to as "sour" soil. The degree of acidity plays a crucial role in overall plant health and performance of vegetable crops. Moderately and highly acidic soils (pH 5.5 and lower) need neutralizing with lime in order for plants to grow best. If you have a soil pH in the range of 6.0 to 7.0, you have met the goal of prime soil pH conditions. In this environment, carrot, beet, cucumber, eggplant, leek, lettuce and tomato prosper. The majority of all garden vegetable crops perform well in this soil.
A neutral soil pH condition occurs at 7.0. "Near-neutral" soils (pH range 6.5 to 7.5) support vegetable plant life well, and is second only to slightly acidic pH soil with regard to optimum conditions. Modifying near-neutral soil pH is easy, as organic soil amendments and mulches with acidic humus gently lower the pH so that a neutral soil becomes barely acidic. Onions relish near-neutral soil conditions.
Alkaline, or "sweet," soil limits the amount of nutrients available to plant roots, making it the least desirable condition to have in the vegetable garden. Some plant crops may grow better when the soil pH is barely alkaline (pH 7.5 to 8.0). Examples include okra, yams, peppers and parsley. Many herbs favor nonacidic soil. Use of sulfur-based fertilizers and acid-forming organic mulches like pine bark, oak leaf mold or coffee grounds helps lower pH into neutral or slightly acidic realms. Avoid highly alkaline soils (over 8.0), because changing the pH drastically costs money and extensive labor.