A new energy-efficient solar greenhouse in Daqing city was tested to see how well it kept warm in winter. Compared to a regular greenhouse, this new greenhouse stayed above 12℃ at night and had more even temperatures. The soil in the new greenhouse was warmer, especially deeper down, than in the regular one. It means the new greenhouse not only warms the air better but also heats the soil where plants grow. This could help crops thrive even in cold weather.