The direct purpose of the foundation in a do-it-yourself greenhouse is to serve as good soil for plants. It is possible to install a greenhouse both without a foundation, directly on the ground, and make a concrete strip foundation around the greenhouse or enclose it around the perimeter with boards, sheets of iron, etc. In this case, put a low greenhouse.
Plants in the greenhouse can be planted on warm beds. To do this, chips should be poured onto cold clay with a layer of 20-30 cm. Chips will serve as an insulator and in the winter will prevent the penetration of cold into clay soil, and in summer – from clay to plants. Without oxygen, wood chips remain for many years and regularly perform their functions. On top of it, turfy earth is poured with a layer of 10 cm, and then sawdust, which does not allow weeds to germinate and, like wood chips, provide additional thermal insulation. In addition, sawdust prevents leaching of nutrients from the soil. A 5-10-centimeter layer of earth is again poured over the sawdust, and everything is carefully compacted. Such padding is considered the main and is suitable for growing many crops.
But the most effective in terms of yield are considered greenhouses with a specially built do-it-yourself foundation for high ridges. In order to build a greenhouse as the correct technology suggests, each ridge along the perimeter should be edged with brickwork in 5-6 rows (it is better to use silicate brick). The result is the so-called pockets, the bottom of which is at the level of the soil on which the greenhouse stands. The bottom then needs to be covered with an insulating material, and pour fertile soil on top to the very top of the “pocket”.
The ridges are high, at the level of the hands, which makes it very convenient to care for plants and is especially important for older gardeners. The beds should be no more than 0.7-0.8 m wide so that you can easily reach the farthest planets. The lower soil under the ridges, when it freezes, creates additional thermal insulation, the edging of silicate brick also plays the same role. As a result, ridges raised above the usual level do not freeze throughout the winter even in the most severe frosts.
Southern plants, which in other conditions require additional shelter, winter well in such a greenhouse. Here they naturally survive the winter. By April, they fully come to life and the kidneys appear on them. Parsley and celery in the northern ridges continues to grow in such a greenhouse until mid-January.
Compared to conventional beds on the ground, high beds have many advantages. In the spring, they warm up faster and maintain the temperature necessary for planting plants even without additional heating, for example, using biofuels.
Already at the end of April, in warm weather and after heavy watering, shoots of cucumbers appear on such ridges, and by mid-May watermelons begin to emerge, which, even in the case of frost, are not at risk. In this case, you can play it safe and cover the seedlings with plastic cups.
For the convenience of processing the beds, the distance between them should be no less than the width of the garden car.
It is permissible if the edges of the wheelbarrow “go in” a little on brick “pockets”. The height of the “pockets” can also be equal to the height of the car so that it does not collapse anywhere and stably stays between the ridges. Such a device is very convenient when importing or removing soil from the greenhouse, as well as during harvesting.
To make the greenhouse as comfortable as possible with your own hands, it is better to fill the floor with concrete. It is carried out between ridges with intervals of 2-3 cm. Boards should be inserted perpendicular to the track at intervals of 1 m. When the concrete has hardened, the boards should be carefully removed and the remaining cracks should be filled with sand. Such a path will make it easy to move, especially with a wheelbarrow, and will help maintain cleanliness in the greenhouse.
It is easy to wash a concrete floor with a stream of water from a hose, and water will go to the earth through gaps in the concrete. In addition, if you water the track from time to time on hot summer days, this way you can maintain the right humidity in the greenhouse, which is very important for plants, especially for tomatoes, irrigation of which is unacceptable.
The foundation described above is not only the basis of the high ridges in the greenhouse but also an integral part of the overall design of the lower part of the greenhouse. It should be strong and reliable, since in the spring, during the period of thawing of the soil, cracks can form in it, causing deformation of the arch structure, and if the greenhouse is covered with glass, it will crack.
According to the correct technology, building a greenhouse in order to prevent cracking of the foundation and damage to the structure, it is necessary to take into account the depth of freezing of the soil at the initial stage of its planning. If it is 1.5 m or more, under the foundation along the entire perimeter of the greenhouse, you need to dig a trench with a depth of 1.2 mm and a width of 25 cm. Then, the trench should be filled with sand 20 cm below its edges, and the sand should be compacted tightly. After that, it is necessary to install the formwork around the trench so that it rises above the ground by 20 cm, inside it around the perimeter you need to expand the metal reinforcement and pour concrete mortar into the trench. The result is a strong reinforced foundation with a width of 25 cm and a thickness of 40 cm, encircling the greenhouse and protecting it from soil movements.
The following is a step-by-step description of making a do-it-yourself greenhouse with a wooden frame.