Purchase seeds for a dawn redwood tree from a commercial seed provider. This tree is still rare in United States, so a sapling is unlikely to be available from a nursery. Place the seed package in the refrigerator until autumn.
Find a planting site for a dawn redwood, ensuring that it has sufficient space for this extremely large tree. The planting site should be in full sun with rich humus soil. The soil can be very wet and may even be in a swamp. The soil pH should be neutral to slightly acidic.
Sow the dawn redwood seeds directly onto the soil, spacing them out at two-inch intervals. Cover the seeds with a thin layer of soil just thick enough to keep the light away from the seeds. Cover the seeds with 2 to 3 inches of organic mulch.
Keep the soil moist at all times with regular watering until the seeds sprout in the spring. Remove the weaker seedlings as they grow, ensuring that the remaining seedlings have space between them. Continue removing or transplanting the seedlings until there is only one dawn redwood tree in the planting site.