During the last few years plastic spring season hothouses gained wide popularity.
Out of the total number of plant growing structures only 25 per cent are regular winter greenhouses, the rest are hotbeds and plastic covered buildings.
According to its climate the Russian Federation displays a wide range of natural conditions, not only with regard to the sum of positive temperatures, but also in terms of continuity of lighting, strength of solar radiation, and accumulation of snow-falls.
All these conditions introduce a definite character, both in the construction of greenhouse combines and in the choice of the respective varieties of greenhouse crops.
Ever since 1958 the construction of greenhouses has been concentrating around the large towns and industrial centres.
A specific branch of agriculture came into being - the year-round production of vegetables.
Utilizing the heat of the big industrial plants, the hot waters of the thermo electric power plants, mineral waters and special thermal stations, working with natural gas, a great number of greenhouses were erected and further developed into specialized vegetable growing state farms near Moscow, Leningrad, Gorki and in other regions.
Thus in Sverdlov region about 45 hectares of greenhouses were erected during the last 10 years and the production of early vegetables in the region has increased for the same period 25 times.
A greenhouse combine is being erected at present around Kamchatka which will utilize the heat of the nearby warm mineral waters.
The building of greenhouses and hotbeds has considerably increased in the past 10 years which have made it possible for the greenhouse vegetable production to increase 4-fold, assuring a greater amount of seedling material for crops growing in the open.
Every square meter of heated glasshouse area on the specialized farms yielded an average of 27.3 kg of vegetables in 1968.
The improved agricultural practices in greenhouse production made it possible for these farms to grow 3–4 different vegetable crops currently per year, using an additional electric lighting source in the early dates of sowing and growing of the seedlings.
The variety of the natural conditions in the Russian Federation imposes certain peculiarities in the zonal agricultural techniques applied both with regard to the sowing dates and in respect to the composition of the soils and the concentration used for foliar application of fertilizers.
For example the marshy lands in the Bouryatska ASSR, covered with mossy turfed clods of earth, are utilized for growing cucumber seedlings.
The procedure applied consists in crushing the clods into pieces.
Smaller cubes are formed then, which are treated with steam or warm water,