How can algae growth affect greenhouse irrigation systems and how can it be controlled?

• A. Algae growth is not an issue in greenhouses.
• B. Algae clog emitters and reduce flow; control with filtration, UV sterilization, chemical algaecides (as allowed), and keep lines clean.
• C. Algae should be encouraged to improve water quality.
• D. Only manual removal is sufficient without filtration.

Answer: (B)

Algae growth in greenhouse irrigation systems can clog emitters and reduce water flow, which disrupts uniform irrigation and can skew nutrient delivery to plants. The best way to handle this is to combine preventive and control measures: filtration to physically remove algae and debris before water reaches the lines, UV sterilization to inactivate algae cells as water moves through the system, and, where allowed, chemical algaecides used in accordance with crop safety and label directions. Keeping irrigation lines clean through regular flushing and routine maintenance is also essential, along with minimizing light exposure to the water by using opaque tanks and covering reservoirs to slow or prevent algal growth. Also consider practical practices like storing water away from light and ensuring proper line hygiene to reduce nutrient buildup that feeds algae. These approaches work together because algae can quickly regrow if only one method is used. Simply removing algae manually isn’t enough, since regrowth and biofilms can quickly reform; relying on filtration, sterilization, and diligent cleaning provides ongoing control.