Raspberries are generally started from cuttings, transplants or root stock. Starting from seed is a tad more difficult but certainly far from impossible.
The best time to start from seed is in early Autumn indoors. Starting indoors in the fall will allow the plants to reach a satisfactory level of maturity come spring when you will be either transplanting them into the garden or in some case pots and containers.
Seeds can be purchased through a number of sources as well as extracted from fresh raspberries. You’ll want to certain the variety you are saving seeds from is suitable for your climate zone.
Raspberry seeds do not require fermentation as some plants do, so seed saving is a snap. To save seeds from fresh berries gently mash overripe berries in a metal strainer or sieve to loosen up and separate the pulp. Rinse it under running water, and allow to dry on a paper towel or cheese cloth.
Once you’ve secured seeds that are suitable to your hardiness zone you’ll need a sterile potting soil or seed-starting compost.
Soil designated for seed starting is best – it is lower in nutrients than standard blends which is necessary for optimal seed starting. The seeds contain all the nutrients they need to start life within the seed shell. Adding more nutrients prior to germination will do more harm than good.
Starter trays are best in my opinion, but other containers will suffice. Press 2 to 3 raspberry seeds about 1/4 of an inch into the soil of each cell. The same as planting any other seeds in starter trays, gently compact the soil to remove excess air space.
Moisten the soil lightly , just enough to dampen . Keep the soil moist throughout the entire germination process, not soaked – just moist, too much moisture / water can lead to fungus and decay and destroy your raspberries before they even sprout. A mister will work well for this task.
Place the seed starter tray in a cool, dark area till germination, which can take about 3 months, although this varies depending on cultivar and growing conditions. A “cool dark area” should be above 35oF.
Assuming you planted your seeds in Early Autumn, they should be sprouts shortly after the Winter Holidays – the time of year when only the most dedicated gardeners are thinking about their gardens.
Set the seed starter trays in a sunlit area once the seeds begin to sprout. If this is not feasible, set up a grow light and place the seed starter tray underneath.
Continue to keep the soil moist {not soaked} and provide the raspberry plants with sufficient sunlight or appropriate artificial light as they continue to grow.
Transplant the raspberry plants outdoors in early spring, as soon as the soil is workable. You might also want to harden them a day or two beforehand by setting the trays outdoors in the breeze and cooler climate to get the plants acclimated.
The transplants should be planted in early spring as soon as the soil can be worked. Keep the plants cool prior to transplanting , if your seedlings can’t be planted right away they should be heeled in or stored.
Don’t allow the plants to dry out during planting .The portion of the stem that was below ground is a different color. The hole should be big enough to allow the roots to spread out normally.