Great question!..
Not knowing the real details about phytochemicals and hormones and such I dont have an 'educated' response but here's my 2 cents...
A 60w bulb puts out 800 lumens..
And to quote Wikipedia on light intensity and inverse square law.. "The
intensity (or
illuminance or
irradiance) of
light or other linear waves radiating from a
point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the
energy (in the same time period)."
That being said if your incandescent light is 10ft away, its going to have almost no lumens compared to your grow light.. Will this affect hormones and phytochemicals? I have NO idea lol... But If you HAVE to have this light on, I really dont think its going to matter