Sowing & Growing

Spindle Tree seeds possess a profound dormancy, requiring patience to overcome. High germination levels are easily achievable by following the correct procedures.

Start by preparing a well-draining substrate, such as a 50/50 mix of compost and sharp sand or perlite/vermiculite. Ensure the substrate is moist but not wet—too much moisture may drown the seeds. Mix the seeds into the substrate, maintaining enough volume to keep them separated. Place the seed mixture in a clear plastic bag (zip-lock bags are ideal, leaving a small gap for air exchange) or loosely tie if it’s not zip-lock. Note the date on the bag for reference.

Begin with a warm pre-treatment, keeping the seeds at 20 degrees Celsius (68F) for at least 8 weeks. Prevent the pre-treatment medium from drying out during this period.

After the warm pre-treatment, initiate a cold period by placing the bag in the fridge at 4 degrees Celsius (39F) for at least 8 weeks (up to 16 weeks for signs of germination). If germination occurs in the bag, carefully remove the seeds and plant them. Once the pre-treatment is complete, the seeds are ready for planting.

For small quantities, sow seeds in pots or seed trays filled with good-quality compost, covering them with a thin layer no more than 1 cm deep. For larger quantities, sow in a well-prepared outdoor seedbed after completing the warm and cold pre-treatments.

Fluctuating pre-treatment temperatures, such as keeping the mixed seeds in a cold shed for the cold stage, can yield optimal germination results. Ungerminated seeds can undergo the entire warm and cold process again to encourage further germination.

Avoid exposing newly sown seeds to high temperatures (above 25 degrees Celsius). Keep the seedlings well-watered and free of weeds. First-year growth typically ranges from 10 to 30 cm, depending on germination time and cultural practices. Allow the seedlings to grow for 1 or 2 years before planting them in a permanent position.