Study Shade Net Color Impacts Greenhouse Yield Efficiency

For greenhouse growers, selecting the right shade net can be a game-changer. These versatile tools not only protect plants from excessive UV radiation but also regulate temperature, improve ventilation, and reduce water loss. But with a dizzying array of colors, materials, and shading percentages available, how does one choose the optimal solution?

The two most common shade net colors—black and white—offer distinctly different benefits tailored to specific growing conditions:

Black nets excel at absorbing solar radiation, making them ideal for:

• Extending growing seasons in northern climates by warming greenhouses in spring and fall
• Reducing diurnal temperature fluctuations (studies show up to 8℉ nighttime warmth retention)
• Preventing photoxidation and sunscald in heat-loving crops like tomatoes and peppers
• Minimizing blossom-end rot in tomatoes (as demonstrated by University of Connecticut research)

White nets reflect sunlight to create cooler microclimates, offering:

• Up to 15℉ temperature reduction in southern climates
• Uniform light diffusion that prevents hot spots while maintaining full-spectrum light quality
• Reduced energy costs (less need for cooling systems)
• Improved root development and stress resistance in cool-season crops like lettuce and spinach

The percentage rating indicates how much sunlight is blocked. Key considerations:

• 30% shading : Ideal for northern climates (above 40° latitude) or mixed vegetables
• 50% shading : Recommended for southern regions or light-sensitive crops like lettuce and flowers

Emerging aluminum-coated nets offer unique advantages:

• 65% light diffusion at 50% shading (vs. 50% in traditional nets)
• 8℉ nighttime temperature increase in northern greenhouses
• Higher cost (4× traditional nets) with 3-5 year lifespan indoors

For tomato seedlings: Use 30% black nets during hardening-off in cool climates to provide warmth while allowing 70% sunlight penetration.

For leafy greens: White 50% nets prevent bolting in arugula and spinach during summer months.

University studies suggest:

• Utah State research: Black nets increased tomato leaf area by 40% and marketable yield by 50%
• Oklahoma State findings: Colored nets (red/blue/green) can influence plant morphology for specialized applications

The optimal choice depends on your specific climate, crops, and seasonal needs. Many successful growers use a combination—white nets for overall cooling with black nets strategically placed over heat-loving crops. As with all agricultural decisions, careful observation and record-keeping will reveal the ideal solution for your operation.