Nano meters and wave lengths
To understand the use of supplemental lighting and adding additional colours, you must understand what type of reaction each wavelength will cause in each plant type you grow.
The main drivers of photosynthesis are Chlorophyll A and B these 2 photosynthetic ranges are the main sources of PAR Photo-synthetically Active Radiation
Phytochrome PR and PFR are associated with wavelengths further up the scale, 660nm and 730nm deep red and far red.
These wave lengths are known to promote germination, plant growth, leave building and flowering.
Using a combination of intensity, timing and variation of colours for different growth stages and plant type you can affect flowering time and decrease time to harvest.
We see this in the Emerson effect which we have have been utilising for a number of years . Deep and Far Red mixed at a ratio of 3-1 Deep red to Far red will speed up plant metabolism. Other effects such as flower initiation are already being utilised as well.
An additional growth curve lighting manufactures use for horticulture is the McCREEs action spectrum. This encompasses all of the other growth curves into one overall curve.
When we measure full spectrum LED the McCrees Action Spectrum gives us the best overall analysis.