What is shade cloth and do I need it on my greenhouse?
If you live in a humid area, misting or fogging may not be enough to cool your greenhouse in those hot, humid summer months. When all else fails you can create your own shade by putting shade cloth on your greenhouse.
Shade cloth is a commercially available material for hanging over your greenhouse glazing to cool it in summer months. They are usually made of loosely woven polyester or even aluminum and can be found in varying densities or degrees of shade from appx. 5% to 95%. Remember that shading will affect your plant growth so chose as low a density as you can get away with. Most plants will do best with a maximum of 40% - 60% shade.
When growing orchids, 75% or higher maybe needed to get correct light levels.
Choosing a shade cloth with grommets will make it much easier to install. Use nylon cord or rope to secure the shade cloth to your greenhouse frame. If your greenhouse has roof vents that open you may have to install your shade cloth in sections to accommodate this. Shade cloth is open weave fabric so it can go directly over windows. Its best to attach the shade cloth so it can be rolled up or retracted as needed.
There are also compounds available to be applied to your greenhouse glazing. These will wash off if you receive much rain and have to be reapplied. If you get one that is not water soluble then you have to use a cleaner to remove it when summer is over.