**1. Introduction**

Vegetable production is an applied scientific discipline that studies biology and technology of vegetable crops growing in open field and greenhouses. The main target is to gain high-yield vegetable crops, high quality of edible parts that have to be safe for human consumption, and preservation of the environment. Vegetables are divided into annual, biannual, or perennial herbaceous plants, which rarely develop a woody stem by the end of its vegetative period, mostly in the lower section of the stem. The vegetable edible parts are rich in water (mainly about 95% of water), and can be used fresh and raw, or processed. Once picked, the edible parts may be stored for a short period of time (several days, up to 9 months at the most, what depends on type of storage place and its equipment). The vegetable edible parts are as follows: roots and tubers, stems and stalks, sprouts, bulbs, leaves, leaf stems, immature inflorescences, fruits (mature or immature), and seed (mature or immature). Due to data of UN DESA [1] report about world increasing population in the coming decades (about to reach 8.5 billion by 2030, then 9.7 billion in 2050) decreasing labor-intensive climate changes, it is necessary to consider new solutions in food production, in general. From that point of view, it is interesting to consider current advantages of crops growing in various protected areas, especially in modern greenhouses. Primary plant production is a part of fresh and processed food production, which requires innovative methods of current types of plant growing or new technologies. It is important especially in greenhouses with or without daylight, where it is necessary to apply innovative methods, software, various innovative automations in plant production and handling after harvesting, and with full equipment, which would provide necessary climate conditions for successful plant empowerment. In brief, it means further developing and applying in practice the newest crops production technologies in modern greenhouses, with high commercial effect, too. On that way, it would be possible to get healthy, highquality, and safe food, and provide high protection of the environment and economy results. Vegetables are used in pharmaceutical industry, too, because of medicinal compounds. In general, vegetables are of low-calorie, low-fat, and lowprotein comestibles. At the same time, they are a significant source of some of the most needed vitamins, minerals, and microelements in human consumption. Average recommended vegetable intake in human consumption is about 400 g per day [2]. There are interesting dietary guidelines for vegetable consumption that the USDA posted on their Web site (USDA Dietary Guidelines for Americans). There is a detailed description of daily servings of vegetables for people living in different parts of world. There are numerous advantages in growing vegetable crops in modern greenhouses compared with the traditional production or with the production in ordinary greenhouses [3]. In modern greenhouses, particularly in the glass ones, it is possible to control the necessary climate conditions entirely. One of the advantages is a possibility of growing vegetables in periods when it is impossible to do in open field. This enables all-year round and/or off-season production, which is increasingly in demand in markets all over the world. This particularly goes for vegetables crops typical of warm season (tomatoes, cucumbers, peppers), but also for those of cool season (lettuce, spinach, radishes, broccoli). In Serbia, winter production of vegetables, as an off-season production, generally is not economical as the renewable sources of energy (geothermal, solar, wind, biomass, etc.) are not still in use in their full capacity. However, the significance also lies in a possibility of arranging for early and late greenhouse production of warm climate vegetable varieties. In early spring and late autumn, the warm climate vegetable varieties cannot be grown in open-field environment, although there is a high demand for them, as well as with high prices. During the cold periods, greenhouses can also yield the cool-season varieties (lettuce and spinach), which are also in high demand on the market. By combining the warm and cool-season vegetable crop varieties, the modern greenhouse can be used for almost all-year round and saved in the deep winter, when it is freezing cold, and the energy prices in Serbia are rather high. The winter period, when no vegetables are grown in the greenhouse, usually can be used for cleaning, disinfecting, and preparing it for the new season and new crops. In most of the North-West European and in some East European countries, a winter break in the greenhouse vegetable crop growing lasts from the end of November until mid-January. The USDA organization has developed a software program called a *Virtual Grower* that helps growers calculate the heating costs of their greenhouse. Users can use the software to predict heating and energy use specific to their location, greenhouse design, crop produced, and the management preferences. The software program, as well as a short video, can be downloaded for free from the

#### *Advantages of Growing Vegetable Crops in Modern Greenhouses DOI: http://dx.doi.org/10.5772/intechopen.101469*

following Web site: https://ag.umass.edu/greenhouse-floriculture/fact-sheets/ virtual-grower-link-to-usda-software.

Due to specific climatic conditions, in southern parts of Europe, a great number of warm-season vegetable crop varieties can be grown all-year round in both the greenhouses and open field. That means that the vegetable crop growers from South Europe are in a much better position when compared with those from the cooler regions of our continent. However, even in those countries with warm and humid or warm and dry climate, there are periods that are not so favorable for the openfield vegetable crop growing or in simple greenhouses (e.g., plastic tunnel greenhouse). Therefore, a well-equipped modern greenhouse is the only wise choice in vegetable crop growing. Hemming et al. [4] describe a method, based on a number of mathematical models, which helps in predicting an appropriate greenhouse model for the given climatic conditions. The local climatic conditions (light intensity, temperature, humidity, and wind velocity) are the input data needed for making a greenhouse and vegetable crop growing technology model in a given area. The climatic conditions and crop growth within such greenhouse can be easily simulated [5], and the obtained data can be used as initial information for making greenhouse an economical model. In this way, the most suited greenhouse for a specific area can be designed. The world population is constantly increasing, and it is necessary to find out possibilities for intensifying agriculture in general and horticulture in particular. In this way, it is important to increase the production per area unit, economise on energy (fossil fuels) and water consumption, and use less chemicals (pesticides in particular) and fertilizers, thus improving the quality of all the edible vegetable parts, as well as overall food safety. For that reason, it is necessary to expand cultivated land areas under greenhouses (modern glass and plastic ones) and to intensify growing various vegetable crops under such protected conditions. Furthermore, the recognised competent and expert institutions in the field of agriculture should, among other things, organize and arrange for experimentation and testing of new technologies, their further development in horticulture through devising cultivation strategies and skills, and finally, provide education through participation in such projects ("learning by doing"). Therefore, it is important to come up with a good strategy for organizing the entire production, experimentation, and application in practice. It is necessary to do a feasibility study, either a limited or a comprehensive one. With regard to such "preventive" projects, there are other aspects to be considered: A carefully selected location that could be appropriate for devising the crop growing strategy, a greenhouse functional design, laid out project requirements depending on the vegetable growing strategy. Also, it would be very important for the initial projects to be organized and well suited to the potentials of a given location or region. With regard to the preventive measures in horticulture and growth of vegetable crops, operational support and production monitoring of a particular crop may be of utmost importance. So, to that end, proactive management and production planning should be implemented, individual support provided, as well as guidance through learning and working (well-trained consultants), along with a support and production monitoring [6] by foreign experts, that is, countries with already highly developed horticulture.

#### **2. Greenhouse site selection in vegetable crop growing**

A modern greenhouse (a glass or plastic one) is actually a mechanical barrier between the outdoor climatic conditions and the indoor area with the controlled climatic conditions that are optimal for growing the selected vegetable crops. In this way, the vegetable crops are protected from the extreme temperatures, wind, snow, rain, hail, birds, and insects [7]. The work efficiency and productivity in a greenhouse depend on its type and on the type and quality of the indoor fixtures and installations [2]. When selecting a location for building a modern greenhouse, the following factors are to be taken into account:
