Growing seedlings in early spring under arcs has a certain drawback: warm air rises to the very top of the shelter, and seedlings are in the colder zone. I managed to find a solution to the problem that helps to get excellent seedlings every year.
From plastic bottles filled with water, I build a platform that has a variable height. First, put the undersized seedlings as high as possible, but as it grows and the air warms, I reduce the height of the platform. I place the bottles flat on a stack of 2-3 layers and cover them with an old film under which warm air is held. Such a platform well accumulates daytime heat and gives it up at night. To protect plants from northerly winds, it is possible to construct bottle walls at the ends of the nursery. I clog all the free cavities of the nursery with this simple building material. The edges of the film do not tear if pressed with water bottles. The nursery is located on the south side of the building. If necessary, I insulate the northern part and part of its roof additionally. When freezing to -3 ° C, it is enough to cover the nursery with a film, and at -5 ° C I use different rags. As a result, even with a cold wind, young plants are not damaged.