What pH Do Raspberries Need to Thrive?

Recommended Soil pH

• Raspberries grow in a variety of soil types, but they prefer a soil pH between 5.8 and 6.5, which is moderately to slightly acidic. In alkaline soils, raspberries may develop yellow leaves due to an iron deficiency. Very acidic soils may cause a deficit of some nutrients, as well as too much aluminum or manganese, also resulting in yellow leaves or slow growth.

Raise pH

• Raising the soil pH is a fairly straightforward process. Add 5 to 10 pounds of dolomitic lime per 100 square feet of soil before planting the raspberries. How much you add depends on how acidic the soil is, as well as the type of soil you have. Heavy, clay soils require more lime to alter the pH than sandy soils. For example, if you have very acidic, clay soil, add more dolomitic lime; if you have mildly acidic, sandy soil, add less. Fertilize raspberries yearly with bone meal fertilizer, which adds nutrients and also raises the soil pH. For best results, choose soil amendments based on the results of a soil test.

Lower Soil pH

• If, on the other hand, you have very alkaline soil -- above 7.0 pH -- you'll need to lower it before raspberries will thrive. Till in a lot of acidic organic matter, such as peat moss, leaves and manure, to lower the pH. Add sulfur if indicated by a soil test, but be careful, since too much can harm the soil. Calcium sulfate or ammonium sulfate fertilizers applied in the spring provide nutrients and help lower the soil pH. As with acidic soil, choose amendments for treating alkaline soil based on the results of a soil test.

Recommendations

• Raspberries are hardy, adaptable plants and will likely thrive in all but very acidic or alkaline soils. If your soil has a very high or low pH, consider planting berries in raised beds and replacing the soil altogether. Add organic matter to ensure that the soil drains well. Provide at least 1 inch of water weekly during the growing season for good berry production. Mulch the plants with straw or untreated grass clippings to keep weeds down and conserve moisture.