Hydroponic farming

Simply put, it is the art of growing plants without soil. This growing of plants in a nutrient solution root medium, is a growing area of commercial food production. The process may include sand, gravel, rock wool or liquid, with added nutrients but without the use of soil.How this process works without soil is quite […]

Simply put, it is the art of growing plants without soil. This growing of plants in a nutrient solution root medium, is a growing area of commercial food production. The process may include sand, gravel, rock wool or liquid, with added nutrients but without the use of soil.
How this process works without soil is quite simple; a plant, given exactly what it needs, when it needs it, in the amount that it needs, will be as healthy as genetically possible. Ensuring this is easy with hydroponics, while in the traditional use of soil is more difficult. With Hydroponics the plants are grown in an inert growing medium and a perfectly balanced pH adjusted nutrient solution is delivered to the roots in a highly soluble form.
Growing medium refers to a vast variety of material in which the roots of the plant are growing, which may include gravel, sand, coconut fiber, perlite and many more. Growing material does not supply any nutrition to the plants, as all the nutrition is received from the nutrient solution thus giving total control to the farmer on everything the plants receive.
There are many different methods of hydroponics, but the base of it all is the nutrient solution. The use of the highly soluble nutrient form allows the plant to easily uptake nutrients as opposed to in soil where they would have to search and extract, giving more energy into vegetative growth and fruit and flower production.
The nutrient solution is the combination of water and fertilizers, with the farmer getting to dictate how much and of which nutrients they wish to give to the plants. Fertilizers intended for both hydroponic and soil use contain the three major nutrients; nitrogen, phosphorus and potassium. Hydroponic fertilizers however contain the proper amounts of all the essential micro-nutrients and are usually in a more refined form with lesser impurities as opposed to soil fertilizers.
Advantages of Hydroponics include:
• No need for huge farming land as it allows the crops to be produced in greenhouses. A stable technology for growth of plants and ensures high yields.
• Less water is lost through evaporation and runoff.
• No mulching, tilling, changing of soil and weeding required.
• No scope of pesticide damage.
• Easier to get rid of pests and diseases.
• Easy to harvest.
• Lower water costs as water is reused.
• The desired nutrient environment can be easily provided for plant growth.
• Proper aeration of nutrient solution is possible; nutrition pollution is not released into the environment.
Disadvantages however, include:
• Limited production in comparison to field conditions
• Technical skill is required to maintain the equipment.
• If the hydroponic system fails it can lead to rapid plat death without soil as a buffer.
• Initial setup cost is high, as the equipment is expensive.
When starting up hydroponics, one has a choice of either designing and building up their own set up, buying a package from a consultant or buying a complete turn-key package. None of these approaches have been known to guarantee success or failure, as that has been determined by the management practices.
It is gravely important to understand the needs of the crop in interest, the market for it and the hydroponic techniques. When buying the systems, one should carefully look into the reputation of company they are buying from, more especially since it is most likely to be outside Botswana. Getting into such a new approach locally, one should be able to learn a lot and benchmark on other success projects. Good planning is critical in this type of farming.
After setting up the hydroponic system, it is important to know how to make the nutrient solution. There are a few things to consider when preparing a nutrient solution; water quality is one of them. The type of water you have will determine the type of nutrient to add, as this will enable you to easily and better balance the CF and PH levels of your solution.
Fresh clean tap water being used as a base has proven to be the best option as opposed to using filtered or bottled water. The principals for making the nutrient solution are the same regardless of the type of system in use. A CF truncheon and a PH meter will be needed to measure the levels of the mixture. A tank or reservoir may be used to mix, and firstly, it is filled with fresh cold water.
Cold water is preferred as it contains more oxygen, hot water can be added sparingly to get a temperature of around 60 degrees. After deciding which nutrients your crop will need, add them to the water. Slowly put in the nutrients to get to your desired level, checking with the truncheon/meter as you go. Nutrients are measured using a CF truncheon, with the level you need to set your solution depending on the crops you are growing, and the stage you are at within the grow cycle.
After adding the nutrients enzymes follow. Enzymes are important as they put all the micro-biological chemicals that plants need into the solution. Once the solution has been vigorously mixed, the PH level is checked and altered if needed. Once the desired PH is reached, the solution is circulated to your plants.
It is recommended to totally replace all the solution at some point during the growth cycle, with routine intervals of once a week recommended. This will ensure the solution is kept clean and fresh which should mean healthy plant and bigger yields. One should check their solution and ensure it is correct before circulating it, as nutrients cannot be adjusted once the solution is circulated. After circulating the solution for a few days it is possible that the nutrient level will rise, often due to the plant taking up the water and leaving the heavier salts in the tank, in which case, fresh water can be added with PH levels also being checked.

Source: AgriBusiness Forum Data base, Botswana