Rubus idaeus – Red Raspberry (Organic)

Germination Instructions

HOW TO GROW RUBUS IDAEUS (Red Raspberry)

NOTE: Red Raspberry plants will rarely fruit in warmer Sub-tropical and Tropical gardens and are recommended for Cold and Temperate climates.

Step 1

Soak seeds in water of room temperature for about 24 hours, changing the water after 12 hours.

Half fill a plastic zip-lock bag with a pre-moistened seed raising mix, sphagnum moss or peat moss (make sure none of these are too wet – if you can squeeze water out of it with your hand, it is too wet!), write the date on the bag, mix in the seeds loosely and place bag into the fridge for 8 weeks.

This process is called ‘cold stratification’ and is done to trick the seeds into believing they are going through a cold winter as they would in their natural habitat.

The seeds may not germinate if they have not been put through this process or germination rates will be lower & can take much longer.

A less successful but easier method is to sow the seeds around late-autumn and keep the soil moist throughout winter. Seeds will then sprout as the warmer weather returns in spring.

Step 2

After 12 weeks, sow each seed about 3mm into seed trays of seed raising soil that is rich in organic matter. Moisten with a spray bottle to avoid over watering and then move into a well-lit but shaded location.

A well-lit location is important as light affects germination rates, however, beware if placing in a sunny location as soil can dry out quickly.

Optimal temperature for germination according to studies is 18°C/64.4°F, however within the temperature range of 15-20°C/60-70°F is acceptable.

Temperatures above 27°C/80°C can cause seeds to go back into a dormant state but have been shown to have germination restart once temperatures dropped and stabilised back below 22°C/72°F.

If your temperatures are much lower at the time of year you are germinating blackberries, a heat mat may be necessary.

You can cover tray with plastic wrap to keep warmth and moisture inside the tray. Seeds should start to germinate between 6-12 weeks and can be sporadic, so don’t give up on any that haven’t sprouted until after 12 weeks!

Step 3

Once seedlings are looking strong, they can be moved to a sunnier location but be careful doing this in warmer months. If you need to do this, do it slowly so that seedlings have the time to adjust.

Seedlings can be transplanted once they reach 3 inches in height into a good quality, nutrient rich soil. Raspberries prefer a slightly acidic soil to thrive, anywhere between 6.0 and 7.0 is ideal.

Keep in a small-medium pot until after first winter, so they can be moved inside if needed to protect them from frost and cold winds at this time.

Seedlings can be fertilised monthly with a weak organic fertiliser.

Step 4

Transplant to final position after last frost has passed, when the plants are between 1-2 years old. If planting more than 1, space 1.5m apart/5 feet.

Again, be aware not to bring the soil to a too alkaline level. Using organic matter such as compost, food scraps, coffee grounds & manure are good organic ways of improving your soil.

During winter plants will often die back and wait until spring to regrow. Raspberries will survive severe cold, even down to -20°C/-4°F

Additional water advised when fruiting which is usually around early to mid-summer.

Raspberry plants usually begin fruiting at 2-3 years of age.