Raspberries are a bramble variety that produces sweet berries during the summer growing season. The plants produce fruit on second-year canes, so it is important to follow a pruning schedule to stimulate new growth for future berry production.
There are three types of raspberry plants; summer berry, everbearing and black/purple. The type you choose depending on your growing preferences. Summer berry types produce one harvest of medium-sized, sweet berries during late summer. Everbearing types produce a summer harvest and fall harvest of medium to large berries. The black/purple types produce one harvest of large, tart berries in late summer. Choose a resistant variety to limit disease and pest damage to the canes.
Prepare the planting area at least two weeks before the desired planting date. The best time to plant raspberry canes in late spring, once the risk of frost is past. Raspberries prefer an acidic soil with a pH of 5.5 to 6.0. Test the soil before planting and add amendments to adjust the pH, if needed. Ground rock sulfur lowers the pH number, while limestone increases the pH number. Purchase pH amendments at a garden supply store and follow the application instructions listed on the package. Add 3 inches of organic compost to the soil and use a tiller to incorporate it into the soil. You can do this at the same time as adding pH amendments.
Create mounded planting rows that are 10 inches and 18 inches wide. Space the rows 2-feet apart to allow room for access between the rows and room for cane spread. Dig planting holes spaced 3-feet apart in the rows. Set the raspberry canes at the same depth they were previously growing and pack soil around the roots to hold them in place. Cut the canes to a height of 6 inches after planting to promote new growth.
Place a 3-inch layer of organic mulch over the planting mounds to help limit weed growth and assist with moisture retention. Refresh the mulch each year to maintain a 3-inch layer. Water the soil on a regular basis to keep it evenly moist. Monitor the soil moisture, especially when there is less than 1-inch of weekly rainfall to prevent a reduced berry production. The soil will dry quickly during the prime growing months of June, July and August.
Fertilize the raspberry canes with a balanced 10-10-10 fertilizer at the first sign of bloom and again after harvest is complete. Sprinkle the fertilizer over the planting mounds. Avoid making contact with the canes to prevent unwanted damage from a chemical burn. Apply a generous soaking of water to dissolve the fertilizer and assist with absorption.
Prune the raspberry plants after harvest is complete by removing all fruit-producing canes. Late winter prune the canes to remove damaged and dead canes, or those that have signs disease. Clip 3 to 4 inches off the tips of the canes in spring if there is winter damage.
An optional maintenance step is building a trellis down the middle of each row to give support to the canes. The trellis helps keep the rows neat and prevents large canes from drooping during berry production.
University of Maine Extension: Growing Raspberries and Blackberries
Oklahoma Cooperative Extension Service: Blackberry and Raspberry Culture in the Home Garden
University of Kentucky: Growing Blackberries and Raspberries in Kentucky