Adjusting ph of the water supply is crucial for maximum nutrient availability. It is seldom that the water supply, even from a well, is perfectly suitable (pH 5.8-6.8). The pH always needs some adjustment, either up or down. How to decrease the pH of a nutrient solution Lowering the pH is the most [...]
What is pH pH is the measurement of acidity or alkalinity of a solution. It is based on a logarithmic scale and starts at 0 and ends at 14 where the value 7 indicates a neutral, neither acid or alkaline. If a solution has a pH value below 7 it is called an acid. If [...]
The effectiveness of a pad and fan system will not only depend on the design, but also on the wet bulb temperature outside the greenhouse. It is not the relative humidity, as many grower think that determine the effectiveness of the pad and fan system. The wet bulb temperature will determine to what temperature the [...]
Mechanical filtration is not an effective tool to prevent water borne diseases in NFT hydroponic nutrient solutions. It has been found that the total organic carbon content can reach 20 mg.L-1 for 2-3 months without affecting plant growth. There are many other compounds that attribute to the total carbon mass such as chelates and the [...]
The correct flow rate of closed hydroponic systems is critical for optimal growth of plants. The flow rates are important for all types of closed hydroponic systems such as pure NFT systems, gravel cultures and ebb-and-flow systems. Inadequate flow rate will result in: Reduced oxygen levels at root surfacesIncreased susceptibility of diseasePlants are under stress [...]
The pythium fungus is one of the serious diseases that growers can encounter in hydroponic systems. The disease can be kept at bay if the irrigation system can be closed of from the environment. The best method to control pythium and phytophtera is by maintaining a 2.5% concentration of hydrogen peroxide. It has been determined [...]
Many growers are under the impression that a maintaining a specific pH is essential to optimal growth and good yields. This is a misconception about the effect of pH on plant growth. The specific pH of the nutrient solution does not have a significant effect on plant growth or for that matter the roots or [...]
Nutrient removal is quite often neglected in closed hydroponic systems since it is difficult to measure and control. The reason is that not all nutrients are removed at an equal rate by plant roots. The essential nutrients can be grouped into 3 categories based on the rate of uptake from the nutrient solution. Elements are actively [...]
Refilling nutrient solutions are only required when a closed (NFT) system is used. With open hydroponic systems the nutrient solution is not re-used so no refill solution is required. Very little information is available on the subject and methods should be developed according to system design. Each system will have unique requirements because of factors such as: plant growth [...]
