Seeding and seedling raising in spring usually can't blossom in that year. This may be because the seedlings need to grow to a certain size and can differentiate into flower buds at low temperature. Therefore, seedlings should be raised in autumn and overwinter when the seedlings grow to a certain size. It can safely overwinter at the low temperature of -32℃ in the open field. The author has experimented for many years that sowing should be done about 7 days before freezing at the latest in the northern cold region, so that the seedlings can have a certain growth, and it is better to sow early to make the seedlings have a certain growth. If you raise seedlings in the protected field in spring, you can raise large seedlings in about 6 days, and you usually have to wait for the next year to bloom.