Raspberries are small fruits, similar to the blackberry, that are native to the U.S. They grow on canes, and bare fruit on 2-year-old canes that die shortly after fruiting. Raspberries grow in many colors, from red to yellow and black. Varieties of raspberries are hardy from USDA zone 3 to 10. They need full sun and well-drained, sandy loam in which to thrive. Like other berry plants, raspberries need a certain amount of balanced fertilization.
Apply 2 oz. of 5-10-5 fertilizer to each raspberry plant about 15 days after planting to give the raspberries a boost in growth. Sprinkle the fertilizer at the base of each plant and water until the ground is moist, not soaked.
Mix 1 lb. of 10-10-10 water soluble fertilizer with 5 gallons of water for every 100 square feet of raspberry bushes.
Apply ½ cup of the water fertilizer mixture to the raspberry plants in mid-spring, after the last frost. Water the soil until it is moist.
Give the plants a second application of the fertilizer mix in the early summer or late spring. Water the soil around the plants until it is moist.