Vegetable and fruit growing and ornament planting in low and high systems under environmental conditions created by eliminating external climatic factors is called protected cultivation. Among these systems, there are high constructions protected by glass or plastic, which are called greenhouses. As more crops can be harvested using protected vegetable growing than outdoor agriculture, income increases likewise. In protected vegetable cultivation, tomato growing comes first. Then comes cucumber, eggplant, melon, squash and watermelon growing. These vegetables are grown in greenhouses in three different seasons, namely fall season, single crop winter season and spring season. Different from the outdoor agriculture, protected vegetable cultivation requires some processes. One of them is mulching. Mulching means forming a protective layer of organic or inorganic materials over the soil in order to increase the quality and amount of crops.
Mulching causes heat difference of about 37 to 41°F in soil and gives way to healthy plant growing. Preventing excessive evaporation of soil surface, it decreases the number of required irrigation. Decreasing the humidity in greenhouse, it prevents the spread of some bactericidal and fungicidal diseases. It also prevents salification of the soil. Mulching increases productivity and forcing ranging from one crop variety to another. Mulching has little or no negative impacts. As it decreases the humidity in the greenhouse, it helps the spread of mildew and red spider.
Melon and watermelon grow better on sandy loam or loamy sand, deep, air permeable, nutritionally rich soils free of drainage problem. Melon roots in particular are highly sensitive to oxygen deficiency. Appropriate temperature for melon and watermelon seeds to germinate better is 77 to 86°F. Seeds which germinate under this temperature need minimum 53 to 59°F temperature to continue growing. In addition, the proportional humidity melon and watermelon require in protected cultivation phase is 70% to 80% at night and 50% to 65% during daytime. In coastal regions, melon and watermelon are grown as the second crop in protected cultivation in Spring season. Melon is commonly grown in glass and plastic greenhouses while watermelon in low plastic tunnels. Seeds, which are germinated under 77 to 86°F temperature, are planted shallowly and not too deeply in the prepared pots and plastic bags. They are lightly watered and covered by polyethylene sheet. When the first growing begins, this sheet is removed. If possible, low tunnels can be constructed over these pots or bags grown in the seedbed.