What are the Soil pH Requirements for Tomato Plants?

Optimal Soil pH

• Tomato plants prefer soil that has a neutral pH, which is generally between 6.4 and 7.0. The pH determines the availability of the soil nutrients. If the pH is significantly acidic or basic, you can amend the soil to bring the pH within the optimal range so that the plants can uptake nutrients appropriately. You should perform soil tests before you plant the tomatoes and then every two to three years thereafter.

Amendments for Basic pH Soil

• Basic soil has a high pH, over 7.0. You can amend soil with a high pH using elemental sulfur. Sulfur will lower the soil to the neutral range for your tomato plants. You can purchase the sulfur from garden center retailers. Follow the manufacturer’s recommendations for use based on your garden’s soil type. You can mix the sulfur into the soil before you plant the tomatoes or apply to an established garden as necessary. Apply sulfur in early spring so that the sulfur has time to alter the pH before the plants enter the growing season.

Amendments for Acidic pH Soil

• Acidic soil has a low pH. You can amend the soil with lime to increase the pH to the optimal range for tomato plants. You can purchase lime at home and garden centers. Add the lime according to the manufacturer’s recommendations. Mix the soil and lime before you plant the tomatoes. If you find low pH conditions after the plants are established, add lime beside the rows in the garden. The best time to apply lime is outside of the growing season in either in the late fall or the early spring.