How to Grow Raspberries & Blueberries Together in Clay Soil

Loosen the soil in your garden to a depth of 18 inches, breaking up any large clumps. Choose a sunny location, as both raspberries and blueberries thrive in full sun.

Amend the soil with compost to improve drainage and add nutrients. Both raspberries and blueberries prefer a slightly sandy soil. If your soil has a heavy clay content, adding coarse sand may improve the drainage and improve the pH of the soil. Clay soils tend to be alkaline, which neither berry prefers.

Test the soil with a soil test kit to determine the soil's pH. Here is where growing these two berries together gets tricky. Blueberries thrive in a higher pH, or possible hydrogen, in the soil. According to the University of Maine, raspberries prefer a soil pH of 5.6 to 6.2, while blueberries prefer a soil pH of 4.5 to 5.2. To grow these berries together, try to keep the soil pH at around 5.2 to 5.6 to accommodate both plants by adding either lime to lower the acidity or raise the number, or an acidic mulch such as pine needles to lower the number toward the blueberry bush's preference, or raise the acidity of the soil.

Plant the raspberry canes and the blueberry bush at the same level they were growing in their previous containers. The raspberry vines will need support as they grow. Space the raspberry vines and the blueberry bush at least 4 feet apart to allow for future growth and harvest.

Spread a thick layer of mulch around your berry plants. This will regulate soil temperature and moisture as well as prevent the growth of weeds.

Fertilize both plants twice a year--once growth begins in the spring and again in the early summer as the berries are forming. Use a general purpose, 10-10-10 fertilizer. Always water well after applying fertilizer.

Prune your raspberry canes by removing any dead or broken canes. Raspberries will spread and can quickly overwhelm a garden. Remove any canes growing where you do not want them. According to USA Gardener, blueberries generally don't need to be pruned until after they are three years old, but once they've matured, thin out the old branches to allow air circulation and encourage new growth.

Make sure your blueberry and raspberry plants receive at least 1 to 2 inches of water every week, especially during the summer or periods of drought.