Pinus densiflora, commonly known as Japanese Red Pine, is a beautiful East Asian conifer native to Japan, Korea, and northeastern China. Seeds of this species require cold stratification to overcome dormancy; a 30-day period at 4°C significantly improves germination rates and success.
Before sowing
Seeds benefit from cold stratification period of 30 days at 4°C to break dormancy and improve germination rates. Stratification can be shortened to 6 weeks minimum.
Sowing
What to expect
Tips
Sow seed 1/8 inch (3mm) deep, tamp the soil firmly, and mulch the seed bed to maintain consistent moisture. Sow in individual pots in a cold frame as soon as seeds are ripe if possible, otherwise in late winter. Keep substrate at medium moisture (not waterlogged). Avoid overly wet conditions which promote fungal issues. Patience is essential—germination may be slow and staggered over several weeks.
Sources: Sheffield's Seed Company, TreeHelp.com, Practical Plants, research on Pinus densiflora seed viability
