candle .. its the frequency and intensity of the light that will interfere with hormones in the plant at this stage.. so keeping frequency and intensity of light (as well as time exposed) down to a minimum is the key. anthing greater than the moons glow intensity is bad... if ur past week 3 in flowering and small buds have already been growing for a while, there is really no danger of reversion.. but in the first 2-3 weeks, the light discipline needs to be severe or u will confuse the plant and have budding irregularities..