How to grow Dawn Redwood (Metasequoia glyptostroboides) from seed? A full breakdown of the key techniques

The techniques for growing Dawn Redwood from seed are:

1. Seed collection: Dawn Redwood flowers in early to mid-March, and the cones reach maturity from mid-October to early November of the same year. When the cone scales turn from green to yellowish-brown, crack slightly, and a small amount of seed falls out, the seeds are ready to collect. After the cones are collected, spread them out to air-dry or expose them briefly to the sun; the scales open and the seeds fall out.

2. Seed treatment: Before sowing, soak the seeds in cold water for 3 to 5 hours so they absorb water and swell fully, which aids germination and ensures even emergence.

3. Sowing: From late March to early April, when the soil temperature reaches above 12°C, the seeds can be sown. Either broadcasting or drilling in rows works. For drilling, sow in horizontal rows with a row spacing of 20 to 25 cm, a sowing width of 3 to 5 cm, and a seeding rate of 12 to 25 kg per hectare. Because the seeds are small, light and winged, it is best to mix them with sand or fine soil before sowing; choose a windless day or sow in a low, crouched position to prevent the wind from blowing the seeds away or causing uneven sowing. After sowing, cover with fine soil just until the seeds can no longer be seen, press down lightly, then cover with straw or plastic film to retain moisture and help the seeds germinate and emerge.

4. Tending and management: After sowing, seedlings generally emerge in 15 days and are fully up in 20 days. During this period, keep the seedbed surface moist. After the young shoots emerge, the seed coats come up with them and are easily pecked by birds, so bird damage should be prevented. In the early seedling stage, growth is slow and roots are shallow; in addition to watering appropriately, shade should be provided to prevent sunburn. At the cotyledon stage, fill in gaps while thinning, moving seedlings from dense spots to bare spots so the seedlings are evenly distributed. From June onward, the seedlings enter the rapid-growth stage. July and August are the fastest-growing period, when water and nutrient needs are greatest, so fertilizer and irrigation should be applied promptly, along with loosening the soil, weeding, and pest and disease control to promote seedling growth. In the same year, seedlings can reach more than 50 cm in height and more than 0.8 cm in ground diameter, and are ready to be lifted from the nursery for afforestation.