Greenhouse Management.


Greenhouse production of fresh leafy vegetables and fruits is an important agricultural practice that leads to an increase in production per land, water and nutrients unit. Greenhouse management requires proper knowledge of the climate and suitable environmental conditions for the cultivated crops. To achieve good management practices for greenhouses, the impacts of climate variables on plant growth and production during different seasons should be understood.

Site Selection.
The selection of a proper site for greenhouse construction is considered the first step for sustainable greenhouse production. The main factors determining the proper location and site selection of a greenhouse production area
are the cost of production, quality of the produced yield, and cost of transportation to targeted markets. The cost and quality of vegetable fruits are dependent on the prevailed climate and the greenhouse growing conditions.
Greenhouse Mechanization.
Greenhouse activities can be really labour intensive due to the movement of materials from one place to another. One of the best ways to handle this is by integrating a mechanization system which will help in reducing labour costs and better utilization of the available space in the greenhouse.
Some equipment that are used in greenhouse mechanization include:
  • Seeders- Low-cost seeders that will seed from 1 to 5 flats/minute are available for the small grower. The wand seeder is fitted with needles that pick up seed from a tray and place it in the flat one row at a time. The vacuum template seeder with holes matching the plug tray is connected to a vacuum box. Seeds are released when the vacuum is released. It seeds a whole tray at one time.
  • Carts and Wagons- The use of carts speeds up handling and reduces labour costs. They roll easily through access doors. Their shelves should be made of lightweight materials strong enough to carry the materials without sagging.
  • Conveyors- This can be used as an alternative to moving plants in carts. The system consists of a tubular or angle iron track suspended from the greenhouse or headhouse frame and a trolley-mounted rack that is pushed along manually. Suspending the track over the benches and plants means that no additional aisle space is needed. Curved sections of track are used to get around corners. Switches may be located anywhere in the system to allow transfer from one track layout to another.
  • Watering Boom- Booms can be simple devices made to operate from a winch pulled cart that supports the boom over the plants. They can also be suspended from track mounted to the overhead trusses. Commercial booms generally have computer control that allows double watering, skipping sections, and multiple nozzles that change the rate of application.
Greenhouse Heating.
Greenhouse heating is used in order to provide the optimal temperature for crops growth and humidity management. Heat should be evenly distributed and kept low. Hot air can also be used to regulate greenhouse temperatures. Internal air can be warmed through heat exchange with external source.  Where combustion occurs at the source of the heat, such as in a gas-fired heater, locating the heater outside the greenhouse and using a heat exchange pad to warm the internal air is recommended. This is because the combustion process can result in ethylene production and also water vapour. Ethylene can cause leaf drop and premature ripening of fruit. Increased moisture levels in the air may result in excessive humidity and condensation problems.
Maintaining even and consistent temperatures within a greenhouse means better production and less chance of failure. Heating units should be correctly sized and positioned. A little effort at the start of the process pays off in lower costs and less frustration.
Greenhouse Ventilation.
Proper ventilation should be considered in greenhouse management as regular air exchange will allow crops to thrive and also allow healthy temperature range for crops growth.  There are several ways in achieving proper ventilation one of them being Passive ventilation which is cheap and affordable because it largely depends on mother nature. Wind effects and thermal bouyancy is used to passively ventilate the greenhouse.
Greenhouse active cooling requires mechanical tools like evaporative coolers and fans to facilitate air exchange. All these tools require electricity and are quite costly therefore it is important to iclude passive cooling as it cuts down on electricity costs making it cheaper.
Greenhouse Lighting.
Proper and sufficient lighting in greenhouses is important because light is directly required in photosynthesis and transpiration (water loss from leaves). Light is an essential element for the plant because it controlls numerous events in plant growth developemnt including plant form and structure (morphology), plant orientation (phototropism), and reproduction (flowering).
Some ways to achive proper lighting in greenhouses include:
Greenhouse Irrigation.
Many greenhouse operations rely on irrigation systems for their watering needs therefore, selecting a good irrigation system depending on the need is important for plants growth.
There are many irrigation systems to choose fromdepending on the size of the greenhouse, the types of plants grown and capital availability. Some of them include:
  •  Drip Irrigation Systems- This is commonly used and mostly preferred because it reduces water wastage and is scalable to any size and good for all purposes. It involves the use of a hose pipe with several emitters that release water at set intervals. It can be installed on the surface or burried in the soil.
  • Soaker Hoses- This system is similar to drip irrigation system but it its tubes do not have emitters, instead they are porous and constantly release water to the soil.
  • Over-head Sprinklers- Pipes are placed above the plants and are fitted with nozzles that can be adjusted to varrying ranges.

Overhead sprinkler

  • Misting Spray System- This system is best for greenhouses with lots of seeds that require regular watering. It releases small amounts of water droplets (mists).

Good and proper management of greenhouses results in high yields.

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