Greenhouses require thermal protection work in winter. Although there is solar heating, it cannot meet required temperature conditions for production. Avoid air leakage: inspect plastic films carefully, repair cracks promptly. Compact film with soil to prevent cold air entry. Cover with insulation when no sun; uncover when sun appears to reduce heat loss. For weak seedlings with poor cold resistance, build a small plastic shed on bed edges during bad weather. Double-layer film protection prevents freezing. Irrigation before cold currents increases soil and air temperature due to water large heat capacity. Radiant heating pipes with finned tubes effectively maintain heat; air heat exchange is more stable than traditional fan heating.