Raspberry plants (Rubus spp.) Like wild red raspberry (Rubus idaeus) and black raspberry (Rubus occidentalis) grow best in rich, deep soil and need organic or chemical plant nutrients to grow healthily and produce heavy crops of fruit. Nitrogen, phosphorous and potassium are the three most important plant nutrients, and hydrogenated plants benefit from inorganic fertilizers that contain a balance of all three of those nutrients. Organic fertilizers like blood meal, fish meal and feather meal also provide these nutrients. Raspberries growing in inappropriate soil can suffer from iron deficiency, however specialized fertilizers help prevent this problem. Wild red raspberry and black raspberry are perennial in U.S. Department of Agriculture plant hardiness zones 4 through 9.
Before Planting
Adding fertilizer to the soil before planting strawberries helps break down plant material from cover plants. Growing a cover crop before planting strawberries adds organic matter into the ground and helps supply conditions raspberry plants will need to thrive, but the crop plants consume plant nutrients as they decay. Annual ryegrass (Lolium multiflorum), hardy in USDA zones 3 through 9, is a cover crop that can be planted in fall to supply rich growing states for raspberries the subsequent calendar year. If you grow a cover crop to raise the ground before planting raspberries, dig in the ground and then turn the cover crop into the ground in early spring when daytime temperatures reach about 50 degrees Fahrenheit. Spread a ready-to-use, 12-12-12 balanced fertilizer at a speed of 1/2 pound per 25 feet of plant row, and mix it in the soil. You may either water the website to dissolve the fertilizer into the soil or wait for the upcoming rainfall to do this job.
After Planting
New raspberry plants benefit from fertilizer enzymes following planting. If the ground for raspberry transplants has not been slapped, then sprinkle two ounces of ready-to-use 12-12-12 fertilizer evenly around each plant 10 to 14 days following planting. Do not sprinkle fertilizer closer than 3 to 4 inches from the raspberry stems because fresh fertilizer can damage them. Apply water to have the fertilizer into the ground, or leave the website alone if rain is expected within the next week. Because manufacturers’ instructions vary among products, follow the hints on your fertilizer’s label.
Annual Fertilizer Application
Chemical and organic fertilizers provide nutrients to created raspberry plants. When new growth appears on raspberries in spring, then spread 1 to 1 1/4 pounds of ready-to-use 20-20-20 fertilizer per 25 feet of raspberry plants in a row, avoiding getting the fertilizer on plant stems. There’s no need to water the fertilized soil if rain is expected within the next week. After the raspberry plants start to flower, spread 1/4 into 1/2 pounds of ammonium nitrate or 3/4 to 1 1/2 pounds of fish meal, blood meal or feather meal per 25 feet of row. Fertilize fall-fruiting raspberries again as their fruits start to form. Raspberries also benefit from the nutrients supplied in well-rotted manure or compost. Spread a 3-inch-thick layer of either material across the plants in late fall or winter when their leaves have dropped. Don’t permit the organic mulch to touch with the raspberry stems.
Nutrient Deficiencies
Raspberry plants growing in heavy or alkaline soil can suffer from iron deficiency, which looks like yellow or white leaves with green veins. Proper iron deficiency in raspberry plants by binder a ready-to-use product that is 5.4 percent chelated iron and 12.8 percent manganese in a speed of 2 to 4 oz per 25 feet of row in early spring, or even apply the product based on its manufacturer’s instructions. University and county horticulture departments often provide soil tests for soil pH level and nutrient deficiencies.