Light Surface Temperature and LED Light Spectrum: Why It Matters

Growing plants in the ideal temperature is a critical factor to ensure proper growth and maximum yields. Do you keep your grow space warm enough? If you end up keeping the grow space too warm, this could exert stress on plants. Too cold, on the other hand, slows down the growth. In either case, this will end up reducing yields. However, establishing an ideal grow room doesn’t necessarily mean that your plants are growing in the suitable temperatures.

The latest technology allows the measuring of LST (Leaf Surface Temperature) in your grow room. Most growers try to maintain the ideal air temperature in their growing spaces to keep their plants growing vigorously. The fact is that LED grow lights can play a critical and beneficial role in maintaining ideal LST.

The temperature of the plants and the LST is not the same as the air temperature in the grow space. Measuring the air temperature in your indoor garden is just like measuring the air in our living spaces, which means it is necessary to have a proper temperature suitable for us to live in. The leaf surface temperature is determined by several factors such as air temperature, plant type, light spectrum, and humidity. The good news is that with recent advancements in technology, it has become possible to provide plants with completely optimized Dorm Grow lights which output an ideal temperature and spectrum to help reach the optimal LST spectrums.

LST and Why Does It Matter?

Biochemical reactions can only operate within certain temperature ranges and have a narrower range in which the reactions can proceed efficiently. If there is an excessive increase or decrease in temperatures, the reactions will proceed at a slow pace, or not at all. Metabolism of plants occurs within the leaf (in most plants), and there is an optimal leaf surface temperature range that helps to maximize the growth along with the production of other secondary metabolites such as pigments, resins, vitamins, and flavor enhancing compounds.

You should note that the LST is affected by the ambient air in the growing environment. It is possible to cool the leaves though evaporation occurring in open stomata on the leaf, which allows gas exchange to be absorbed by unused light. If the LST remains within a suitable range, it allows plants to carry out biochemical reactions efficiently.

What Affects LST?

Light spectrum, ambient air temperature, leaf physiology, pigmentation, relative humidity and genetic/metabolic differences all affect Leaf Surface Temperature. The air temperature sets the baseline for the leaf temperature, providing warmth to cooler leaves than the air and vice versa. Most leaves cool all by themselves through the evaporation of water via their stomata. Typically, higher relative humidity increases the leaf surface temperature by reducing the evaporation cooling. The light spectrum also affects LST, by heating or cooling the leaves.

Most studies also show that chlorophyll most efficiently uses red and blue areas of the light spectrum. However, the ideal pallet of colors will include other colors of light for photosynthesis. Light spectrums optimized specifically for plants will thus require a warmer ambient air temperature to keep the leaf surface temperature in the right range than spectrums not optimized. Generally, since heat mitigation is a concern in indoor-grow spaces with artificial lighting, these higher ambient temperatures can help to save significant amounts of money.

Supplemental Grow Lights

Various supplemental grow light technologies available today create different spectrums of light. Compared to other forms of artificial lights, LED grow lights differ significantly from others in that spectrums can be tailored according to plant specification, eliminating excess unwanted wavelength of lights while providing sufficient light fro photosynthesis to take place.

Compared to LED lights, other artificial lighting technologies produce more light as an unintended and avoidable byproduct of how they operate. In the end, this wastes energy and heats up the leaves of plants. Of course, if you use a LED with too many wavelengths of light or an all white LED, this will also waste energy and heat up the leaves of plants.

In particular, HPS (High-Pressure Sodium) lights convert a significant portion of energy consumed by the bulb directly to non-visible infrared light. This infrared light is perceptible to plants by the warmth it gives off, although it doesn’t have enough energy for photosynthesis.

In addition, much of the visible light HPS bulbs produce is yellow, whereas the most efficiently utilized ones by plants are blue and red light, warming up the leaves.

Every grower knows exactly how important it is to keep plants happy under the right temperature for optimum yield. The use of LED light technology allows better control of the spectrum of light and translates into cooler plant leaves at the same ambient temperature. Furthermore,  provide for a healthier plant in a controlled environment.

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