Many successful growers are using a double layer system of shade cloth as technology increases and economics demand maximum production and improved quality. The old methods of providing the proper summer shade and getting through the winter with inadequate light is too inefficient. Modern culture calls for proper light control during the brighter summer days.
Acadian Industrial Textiles furnishes the table below as an aid in determining the correct combination of Shade Fabrics for your crops and conditions. These figures were obtained as in the following example:
One layer of 30% shade cloth is letting 70% of the light through. Adding a layer of 55% shade would actually be shading 55% of the 70%, or 38.5%. Rounding this off and adding to the original 30% equals 69% shade.
Studies need to be done to determine the effect of the distance between the two layers of fabric. Presently, the effect appears to be negligible. The table would not apply when two layers of lathe weave fabric are used.
To use the table: find the shade of one layer in the left-hand column and then go horizontally across the table to the desired shade. When desired shade is found, look at the top row of numbers to determine the shade density of the layer needed to give desired shade.
The above information is based on a mathematical calculation. Before installing double layer, we recommend that you perform actual testing with a shade box to determine the actual shade density.