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.
Benefits of Mulching
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.
Today, one of the most important problems in greenhouse vegetable cultivation is the low soil and atmosphere temperatures in winters. Easy-to-use energy preservation systems, which include mulching, water mattresses, low tunnel and polyethylene sheet practices, create advantage against low temperatures. Diesel or wood heaters as well as air blower heaters are systems used to protect from frosts of short duration. As another method of protection from frosts, spraying saves labor cost, does not contaminate the air inside the greenhouse and increases the usable area in the greenhouse. When water, which is sprayed over the greenhouse freezes, it can easily be used as a heat layer for protection against frosts. It is recommended to consult with experts during project preparation and use of the system.
Melon and Watermelon
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.
In accordance with the results of analysis, organic and chemical fertilizers can be added to the soil, into which melon and watermelon will be planted. After fertilization, the field is plowed and smoothed. Then, masuras are prepared with the measures of 40-20×20 inches for melon and 100-20×20 inches for watermelon, in accordance with the double-row planting system.
After being watered with medicated water, seedlings are planted into the holes digged on these masuras and first water is given. The second irrigation after the first one on the narrow and wide chamber portions is important. The second irrigation should be carried out for melon before the fruits are 1 to 1,5 inches in diameter and for watermelon before they are 2 to 2,5 inches in diameter.
Irrigation in Use
The following irrigations are done in accordance with the state of plant and soil. After watering the narrow and wide chamber portions, one-way hoeing is done when the soil is ready to be cultivated. After the processes of planting, irrigation and hoeing comes the process of covering soil surface with transparent, plastic mulch. While watermelon grows on the ground in low tunnels, melon grows trained on twine.
For forcing and high-quality fruit production in melon, trimming is needed. In one trimming method, side shoots on the stem of the plants are completely pinched out to 20 inches. Shoots that grow after are trimmed to the wire by topping out 1 fruit 2 leaves. For forcing in watermelon, on the other hand, the top of the plants of 20 to 24 inches are cut and side shoots are left to grow. Bees are required for pollination in the protected melon and watermelon growing. In cases where there is no bee, hand pollination is recommended. In melon and watermelon harvest, the determination of fruit ripening is very important.
They Acquires a Glossy Color
In ripe melons, the color turns from green to yellow and cracking occurs where the fruit and stem merge. On the other hand, it is hard to determine whether the watermelon is ripe or not. Ripe watermelons produce a hollow, reverberating sound when slapped with hand. The wax layer over the peel surface of the fruits lessens and watermelon peel acquires a glossy color. The flake on the merging point of fruit and stem dries and fruit stem becomes thinner.
* Wait for the part 2 of this article. We are going to cover other vegetables at part 2.