Snow-covering
A lot of seed, especially cold germinators, need a cooling-period after sowing. It is beneficial to cover the sowing with snow during that period.
The temperature below it usually keeps in the optimum range of -4 to 0°C (25 to 32°F). The sowing is kept moist, and the melting snow helps to destroy the shell, which is advantageous for the germinating seedling.