JessieC But I wonder if the streetlight has been making things harder than they need to be….
If you notice a difference in the number/size/quality of your tubers when you dig (compared to those not near the light) then it is likely because of the streetlight. You would also notice that your double blooms do not go open centered and retain good form until they freeze. (or you dig) The amount of light needed to affect the photoperiod is only about 10 foot-candles at the plant level. I think the red spectrum is supposed to be more effective and I use warm LED bulbs (about 1500 lumens about 6 feet from plants) in the field, but I use cool LED bulbs for cuttings and both spectrums do the job. At my latitude I need about 2 hours of supplemental lighting to keep dahlias fully-double and salable in the winter.
