RIP Neil Peart 9/12/1952 -- 1/7/2020
- Aug 5, 2011
- Reaction score
- HeIl, California.
Props. I have seen that term but I never knew to what it referred.PAR is essentially a measurement of light emission within the photosynthetic range of 400-700nm. This represents the area of light that plants use for photosynthesis, or to grow. PAR is measured by the amount of micro moles of light per square meter per second.