Mechanical filtration of nutrient solution in NFT hydroponic systems
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...
Flow rate in gravel NFT hydroponic systems – crucial for optimal system performance
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...
Serious diseases found in NFT hydroponic systems
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...
How to monitor and control pH in closed hydroponic systems
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...
Differential nutrient removal from hydroponic nutrient solutions
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...
Refilling nutrient solutions and refilling frequency
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...
Lime – a cheap way to reduce greenhouse temperatures
Cooling a greenhouse can be just as expensive as heating, well almost. There are some very practical methods that you can use to save money. ...
Insect screens in greenhouses – effective biological control
Insect screens or thermal screens are designed to reduce heat in summer and increase temperatures during the night, but also to reduce the number of insects entering the...
Thermal screens greenhouse cooling – are they effective
Heat is always a problem in greenhouses during summer months and even during winter in some areas. Extreme high temperatures cause stress in plants and...
Evaporative pads – maintenance in commercial hydroponics
The installation of new evaporative pads is expensive. The material should last at least two years if not more. With good regular maintenance, evaporative pads...
Cooling a greenhouse with evaporative pad-and-fan
Pad-and-fan systems, also called evaporative pad-and-fan systems, is the most common method of cooling a greenhouse in warm weather regions. Although not optimal, it is better...
Cooling a greenhouse with fogging nozzles
Many growers have tried reducing temperatures (cooling) with fogging nozzles. The concept of spraying the air with microscopic water droplets which absorb the heat in the...
Natural ventilation in humid regions.
Ventilation of greenhouses in humid tropical areas presents the grower with a complete new set of problems. There are various methods available but none have...
Natural ventilation of single span tunnels in arid regions.
Arid regions are characterized by low rainfall, low humidity and high temperatures during summer. The largest problem is temperature during the day time inside the...
What is natural ventilation
Ventilation is the exchange of air inside the greenhouse with air taken from outside the greenhouse using either natural or forced methods. Ventilation efficiency...
