Raspberry, Red European (Rubus idaeus) - 30 Seeds
•USDA Zones: 3-8
By far the easiest method is to direct sow outdoors in the fall and let Mother Nature do it's thing over the winter to break the dormancy. Sow at 1/4" depth, 10 feet apart, and 3-4 seeds per plant. Keep moist, but not wet.
Starting inside, raspberry is a long term, multiple stage process that needs BOTH scarification (soaking) and stratification (warm/cold treatment) to break the dormancy. Basically, we're trying to replicate what occurs naturally in nature ( berries fall, rot, seeds warm over late summer and fall, go through the winter to break dormancy, and then germinate in the spring). It's a long process, but one that we find is extremely rewarding.
STAGE 1 - SCARIFICATION
The slower, but safer and easier method is to soak the seeds in HOT (175F) water for 10 minutes, allow to cool and continue to soak at room temperature for 24 hours. The fastest method is to soak the seeds in sulfuric acid for 10 mins and then thoroughly rinse. The seeds are then ready for Stage 2.
STAGE 2 - WARM STRATIFICATION
After the soaking (scarification), the seeds will need to go through a warm period. In a plastic container or zip lock bag, fill it partially with peat moss. Next, put a layer of paper towel down on top of the peat moss and dampen it. Now, lay the seeds on top of that paper towel. Then add another layer of paper towel on top and dampen it. You're basically making a seed sandwich....
Once that is complete, put the bag/container in a warm area (72-75°) for 60 days occasionally check it to make sure it remains moist.
STAGE 3 - COLD STRATIFICATION
After the warm stratification, we will move to a cold period to break the dormancy. Place the damp peat moss seed bag into the refrigerator for 60 days occasionally checking to make sure moss remains damp.
STAGE 4 - FINALLY READY TO SOW
After that process (I know it's long), sow seeds at 3-4 seeds per pot at 1/4" depth with pH 5.2 to 5.14 mix and put pots in a warm, sunny area. Water regularly to ensure the soil is moist, but not wet. Allow 45 days to germinate.
STAGE 5 - TRANSPLANT
Congratulations!!! The seedlings can now be transplanted when they are a few inches tall after the threat of frost has passed.