Shade Cloth and Other Effects of Light on Plants

Sunlight can be very strong in the desert. In other parts of the country where sunlight is more "normal", shade cloth might not be needed. Desert sunlight can be very intense at times. It makes sense with some plants to reduce light intensity with shade cloth? But how much? Which plants?

Intensity

The effects of sunlight (or light) can be broken down into the quantity of light plants receive and the quality of this light. Light quantity refers to its intensity, or how strong this light can be. 

Intensity of sunlight refers to the quantity of light plants receive. Some vegetables give us better plant parts with a little bit of shade. This is 30% shade which is about right for a lot of leafy vegetables growing in the intense desert sunlight. This may be too much shade for some flowering vegetables like okra.

The 30% shade cloth was doubled over to give 60% shade in this darker area of the grow tunnel. Usually anything above about 40% shade will prevent a lot of vegetable growth and production.

Light Color

The color of light can also affect plant growth. Red light promotes flowering while solid blue light discourages flowering. Research has demonstrated that different colors of light in combination can promote certain types of plant growth. Should you as a homeowner use different lights? Probably not but it might be worthwhile if you grow plants commercially.

For more information look at https://sensing.konicaminolta.us/us/blog/can-colored-lights-affect-how-plants-grow/

At Dave Wilson Nursery near Modesto, CA, here red shade cloth is applied to influence plants.

How Long Light Shines (Photoperiod)

Plants will do different things sometimes at different times of year (mostly in cold climates, rain can play a similar role to light in tropical climates). Sometimes this is tied to how much night time there is or how much rain. Plants cant move around so they are much more "in tune" with their environment and "reading" it.

At this marijuana production facility light is used to provide the energy needed for plant growth. A certain light intensity is needed if any kind of production is needed.

Although not done here, a specific color of light could be used that enhances root production of these cuttings. Some decisions are better made considering the economics of production.