Par Light Spectrum

Par defines the relative amount of light plants use for photosynthesis in the range of 400 nm to 700 nm.

Par light spectrum. Par is not a measurement or metric like feet inches or kilos. These two readings together will give a complete picture of a light s effectiveness. Par is a much used and often misused term related to horticulture lighting. Photons at shorter wavelengths tend to be so energetic that they can be.

Scientists have come up with a better way measure light for plant growth called par photosynthetically active radiation. The ideal grow light spectrum for plants depends on several factors. This light can help accelerate flowering increase nutrition speed up rate of growth etc. The ancient greeks recognized that light traveled in straight lines and studied some of its properties including reflection and refraction the study of light continued and during the 16th and 17th centuries conflicting theories regarded light as either a wave or a particle.

As photosynthesis occurs the wavelength spectrum that is most beneficial to plant growth is found within certain areas between the 440 700 nanometer ranges of the spectrum the light that is within this region is referred to as photosynthetically active radiation par. These include how specific plants use par spectrum light for photosynthesis but also the wavelengths outside of the 400 700nm range. Visible light is a mix of different reds blues greens oranges and yellow wavelengths. For instance uv light elicits protective compounds in plants similar to the way humans become tanned in the presence of uv.

Measure photosynthetically active radiation par in µmol m 2 s 1. For most of history visible light was the only known part of the electromagnetic spectrum. Rather it defines the type of. Par showing strength and spectrum showing that this strength is in the proper wavelength proportion for what the plant can actually utilize and not just wasted energy.

Photosynthetically active radiation often abbreviated par designates the spectral range wave band of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis this spectral region corresponds more or less with the range of light visible to the human eye. A spectrum reading is obtained by using a piece of equipment called a spectrometer. Par light is the wavelengths of light within the visible range of 400 to 700 nanometers nm which drive photosynthesis figure 1.