Few treats are more accessible or less expensive than raspberries (Rubus spp.). With their vigorous growth and high quality fruit, raspberries are an ideal plant for home gardens in U.S. Department of Agriculture plant hardiness zones 2 to 7. If you have just one raspberry plant, you can propagate it to fill your whole garden with fruit. Red raspberries are propagated by root cuttings, whereas black and purple raspberries are propagated by tip-layered cuttings.
Select an area that has well-drained soil and receives at least 6 hours of sun per day. Choose an area a minimum of 200 feet away from existing raspberries to help prevent the spread of disease. Avoid areas where tomatoes, eggplants or potatoes have recently grown to help prevent verticillium wilt. If possible, select an area with afternoon shade.
Take a soil sample and apply any recommended amendments from the soil test results into the top 6 to 8 inches of soil. Raspberries thrive in a soil pH between 5.5 and 6.5. If a pH of 7.0 needs to be lowered to 6.0, apply 0.2 pounds of sulfur per 10 square feet. To raise pH, apply ground agricultural limestone. Most soil tests will indicate precisely how much of the amendment is needed to change the pH.
Remove the parent plant from the ground gently with a garden fork during its dormant period, usually from mid- to late-fall or early winter. Wash off the roots to remove soil. Cut off a few young, vigorous roots as close to the crown as possible with a sharp knife. Put the parent plant back in the ground immediately.
Cut the roots in 2- to 6-inch sections with a sharp knife. Use the knife to make a straight cut at the top part of the root that was nearest to the crown. Make a slanted cut at the lower part of the roots, furthest from the crown. Tie the roots in bundles with non-rotting plastic twine or wire.
Fill pots with equal parts of moistened sphagnum peat moss and sand. Bury the roots in the pot so the top parts -- the straight-cut ends -- are at soil level. Water them and put them in an area that is out of direct sun and stays about 40 degrees Fahrenheit. In about three weeks, remove them from storage.
Space red raspberries 2 feet apart in hedgerows set 8 to 12 feet apart, black raspberries 3 feet apart in rows set 8 to 10 feet apart and purple raspberries about 3 feet apart in rows set 10 to 12 feet apart. Till the planting site to a depth of 6 to 9 inches, removing any weeds or grasses within the area. Bury the roots so the top parts are about 3 inches below the soil surface. Water the soil until it is evenly moist.
Bend down the tips of new shoots to the ground in August or early September. Insert the tips in a 3- to 4-inch-deep hole and cover them with soil. Tamp the soil around the tip to help keep it in place. Water it until the soil is evenly moist.
Water the tip consistently, keeping the soil moist until spring. The tip will grow downward first, then it will bend and grow upward. Roots will begin to form at the bend in the fall and new plants will begin growing in the spring.
Cut the tip from the parent plant in the spring, leaving at least 6 inches of the parent plant on the new plant. Remove the new plant from the ground carefully.
Select an area that has well-drained soil and receives at least 6 hours of sun per day. Space red raspberries 2 feet apart in hedgerows set 8 to 12 feet apart, black raspberries, 3 feet apart in rows set 8 to 10 feet apart and purple raspberries about 3 feet apart in rows set 10 to 12 feet apart. Dig a hole no deeper than 1 to 2 inches and plant the tip-layered cutting in it. Water the soil until it is evenly moist.