The Purdue Plant and Pest Diagnostic Laboratory

P&PDL Picture of the Week for
January 20, 2014

Winter Greenhouse Maintenance

Roberto G. Lopez, Ph.D., Associate Professor & Floriculture Extension Specialist, Purdue University

Inflation Fans

Is condensation a problem in your greenhouse (Figure 1)? This can be easily avoided by making sure your inflation units maintain an adequate layer of outside air between the two layers of polyethylene coverings. Greenhouses that use outside air to fill the layer between double polyethylene films find reduced condensation and energy savings (Figure 2).

Ventilation Fans

Consider variable speed fan motors to allow more precise ventilation and reduced electricity use. Remember to regularly maintain belts and motors to reduce friction. This can reduce energy loss by up to 15%. Maintain louver covers on ventilation fans throughout to eliminate gaps when fans are not running, and insulate and seal off ventilation units not in use during the winter (Figure 3).

Click image to enlarge

Figure 1. Condensation forming on a double polyethylene greenhouse.  

Figure 2. This greenhouse is using inside air to fill the layer between the double polyethylene film and will consequently have increased condensation.

Figure 3. Fans that are not utilized in the winter are sealed off and insulated for energy savings.

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service