With all due respect, the best way to look at the light needs is based on the spectrum which chlorophyll A & B absorb. The graph I have included shows the absorption of both (the peaks), and you can see they both absorb light in the blue & red spectrum. In order to optimize the photosynthetic process, you must provide sufficient levels of light in those parts of the spectrum. Simply defining blue spectrum needs as `growing' and red spectrum needs as `flowering' is not aligned with this, although agreed that more red spectrum supports better flowering.
The best technology to provide the right blend of blue/red spectrum are the new LEDs since they combine both blue & red LEDs to provide the perfect light mix - a purple light. This has become a proper science within a certain home growing sector and I have provided a picture of a bulb which clearly shows the mix of blue & red LEDs which is optimized for growing their crop. These are expensive.
For starting tomatoes, fluorescent lights will work fine, and they are inexpensive. I have included 3 fluorescent spectrum for a) daylight, b) cool white & c) warm white bulbs. You can see that all of them provide some degree of blue & red light light. The specially designed fluorescent growlights provide more targeted blue & red spectrum for plants and are `better,' but much more expensive. I once built a graphic which shows all of the floresecent bulb sprecta perfectly aligned with the chlorophyll needs to show which is best, but it is too big to fit into the TV limits. PM me if you want a copy of it.
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