If you want to get good horticultural productions even with very cold temperatures, the solution is to use a protected environment such as the greenhouse. Here is a small guide on how to make it and some secrets for use.
More and more people in recent years have approached the direct cultivation of vegetables and vegetables. A sort of "orthomania", dictated by numerous factors: saving, consuming healthier products, returning to a more correct natural cycle. The best times for horticultural production are those between late spring and autumn, when temperatures are not too rigid and even the most delicate species can grow and bear fruit without too many problems. If you want to continue your vegetable cultivation even in winter the solution is that of the greenhouse, a protected environment that allows you to repair the vegetables from the cold, to have good harvests even in an unfavorable period of the year and start sowing the species which then in spring will be transplanted into the ground for open-air cultivation.
How to make a greenhouse: the supporting structure
There are two possible options for having a good greenhouse quickly and starting your own cultivation in a protected environment: buy it at one of the many specialized garden centers, which usually also include assembly by qualified personnel or - if you want save and at the same time personalize your own greenhouse - build it yourself, with few materials that are easily available and a fair amount of manual work.
For the "do-it-yourself" lovers, the first step is the purchase of the necessary: for a good tunnel-greenhouse (the structure is usually called in this way for the particular shape that characterizes it), it is necessary to use galvanized tubulars from the a few centimeters in diameter, which must be bent - it can be done manually using any semi-circular shape as a lever - in such a way as to assume the classic bow shape. The length of the pipes will then depend on the height of the greenhouse tunnel: an evaluation that must be done beforehand, so as to carefully purchase the material.
Once the tubes have been folded and assumed the desired shape, small hooks made of steel must be welded at the ends, to be used then to fix the cover sheet to the structure.
For a medium sized greenhouse and a family type of use, it is advisable to create an area with a diameter of one meter / one meter and a half and a length of 7/8 meters. It obviously depends on the specific needs, dictated by the quantity of production to be realized. In the case of the medium-typology the arches must be placed, fixing them in the ground with strength so that they reach a safety depth, one meter away from each other. This will make it possible to create a structure that is resistant even to the strongest gusts of wind.
The cover sheets: which to choose and how to fix them
Once the structure has been positioned on the ground, all that remains is to cover it entirely with special sheets. Many variants are available on the market, with characteristics that differ in terms of resistance and performance: for a purchase that is not too expensive and that allows good results, you can choose between PVC or Ethylene Vinyl acetate (commonly called EVA). In the first case, we have an economic material that guarantees a good greenhouse effect, with medium resistance and flexibility characteristics. There are two contraindications: it tends to deform with the wind and therefore in this case an optimally constructed supporting structure takes on a strategic importance and tends to make the internal temperature of the greenhouse rise too much, a problem that can be overcome thanks to frequent ventilation of the environment.
The Eva, whose cost is higher than PVC, guarantees greater sealing and less condensation. It has a further advantage: it lasts longer over time, to the point that it must be replaced every three or four years.
For an average cost and a structure with optimal characteristics, it could be an idea to use both sheets with a double covering, exploiting the advantages of both.
Before proceeding to spread the cloth on the structure, it is still necessary a small operation of particular importance: to pass some wire between all the arches, anchoring them firmly together. The two ends of the wire will then be fixed to the ground in opposite sides by common (but resistant) camping pegs. In this way the structure will resist more to the elements and will not have to rise from the ground, in case of too much wind.
As far as fixing is concerned, it will be sufficient to tie the fabric to the hooks that we previously welded to the ends of the tubes with elastic bands, making sure that the same hooks are at ground level.
The structure is now complete and can begin your cultivation in the greenhouse: to ventilate the room - an operation that must be repeated periodically to avoid unpleasant effects of internal condensation (and therefore humidity) that facilitate the proliferation of mold and fungal diseases. This ventilation - which must be done by lifting a part of the sheet - also allows the internal temperature to be lowered, which increases too much and fatally damages the younger or more sensitive plant species.
Vegetable greenhouse: Summer use of the greenhouse tunnel
The advantage of a structure like that of the greenhouse tunnel is that it can also be used in summer, when too high temperatures can damage or "block" the growth and development of a plant. Another valuable suggestion is to use the cloth also in spring, when the plants cultivated in greenhouses are transplanted from the pots into the soil for outdoor cultivation. To avoid a too traumatic passage from the climatic conditions inside the greenhouse to those of the open air (often even in the first months of spring it is possible to have very rigid days), we suggest using the cloth to cover the young plants, once transplanted into the ground . For the first few weeks they will remain covered and can become stronger and gradually accustomed to full light, sun heat and wind. When the late spring arrives, we could remove the sheet and use it again for the "summer" greenhouse. While our "winter" seedlings will begin to grow constantly and give us the first, good fruits.