Harvest the blackberry fruit. Use fresh berries to gather the seeds, not dried fruit. The germination rate drops when the seeds dry out. Place the fruit in a blender, pulsing on low until the seeds and fruit separate. Strain the berries out of the juice, and pick the seeds out of the pulp with tweezers.
Examine each of the seeds for scratches or nicks. Scratch any seed without damage with a sharp knife. Scarification helps break the strong seed dormancy surrounding the embryo.
Fill seed trays with seed starter soil, and spread the blackberry seeds on top of the soil. Lightly cover the seeds with soil, and place in a warm area. Blackberry seed germination does not require bright light since the seeds are covered with soil. Mist the soil with water in a spray bottle whenever the soil begins to dry out. Once seedlings begin to sprout, move the tray to an area with bright light.
Place the blackberry seeds in a resealable plastic bag along with a handful of damp peat moss. Seal the bag, and place in a refrigerator with temperatures around 33 to 35 degrees Fahrenheit. Keep the seeds chilled for 12 to 16 weeks.
Blackberries (Rubus spp.), which grow best in U.S. Department of Agriculture plant hardiness zones 5 through 10, are commonly propagated through cuttings or division. This method gives an exact copy of the berry bush. It is possible to grow blackberry shrubs by planting seeds, but the seedlings vary in features. The best time to plant young blackberry seedlings outside is in September, but the germination process begins six months earlier.
Remove the weeds from a planting area in full to partial sun. Pick a location with good drainage. Spread a 3- to 6-inch-layer of well-rotted compost over the planting area. Dig the organic material into the soil with a shovel. Work the compost into the top 8 inches of soil. This gives the blackberry plants a good source of slow-release nutrients. Smooth the soil with a rake.
How to Grow Blackberries from Seeds
Dig holes with a hand trowel only as deep and wide as the seedlings’ root balls. Space the holes out 4 to 6 feet apart. Place the seedlings in the holes, and fill with soil. Gently firm the soil around the brambles so they stand up. Space the rows 10 feet apart.
Water the soil around the base of the blackberry plants until it is slightly muddy. Give the berry plants 1 inch of water each week when there is no rainfall during the summer. Spread 2 to 3 inches of organic mulch around the base of the new shrubs. Mulching benefits blackberry bushes by reducing weed growth, slowing soil moisture evaporation and providing slow-release nutrients. Keep the mulch layer thick throughout the life of the blackberry bushes.
Blackberries (Rubus spp.), which grow best in U.S. Department of Agriculture plant hardiness zones 5 through 10, are commonly propagated through cuttings or division. This method gives an exact copy of the berry bush. It is possible to grow blackberry shrubs by planting seeds, but the seedlings vary in features. The …