This isn't true unless you are growing aquatic plants. First, most hardware store bulbs are probably going to be more down in the 4000K range - the yellowish "soft white" bulb color. Second, chlorophyll responds to light throughout the visible spectrum except green. The color temp you choose for plants is purely an aesthetic choice. Full tropical sunlight at noon is about 5000K and bright sunlight filtered through a forest canopy is about 6500K (a little more blue than full sun). So something in the 5000K - 6700K range looks good in a viv and is fine for the plants.booboo said:most hardware store/drugstores light bulbs are 6500. If you were super into plants you would want 10000k with mybe actinic supplementation and if you were realy into it you would probably have metal halide but thtas not your question.