I like to start off the seedlings and the first few weeks of vegetative growth under a compact florescent set up. After i feel the plant is strong enough to take the intensity from the high pressure sodium(it has several sets of leaves), I will replace the CFL”s with a 1000 watt High pressure sodium light. I think this light works great for both the vegetative and flowering cycle of the plants life. You most definitely can get away with using a different lighting system for the entire vegetative cycle. I would highly recommend using these type of lights for flowering though because that’s where these bulbs really separate themselves from the rest. Plants respond better to the red spectrum of lighting for flowering, as it promotes the plant to stretch and bud more efficiently. Plants may also have a faster transition to flower under a light that is closer to the red spectrum.
One of the most important things to consider when choosing to go with a HPS, is cooling the growing canabis environment. There has to be a fan attached to the reflector at all times or it will emit too much heat for your medicine to be grown optimally. As long as the area is well ventilated and you have hot air going out with fresh air coming in, there is no issue with using these lights. Remember that growing canabis temperatures should be between 73-85 during the vegetative stage and you’ll have to compensate for this added heat. A couple feet is a good maximum distance to separate the plants from the glass.
These lights are very powerful and they produce powerful medicine. I remember my very first grow when I wasn’t too sure what I was doing outside of reading, and I purchased a high quality HPS bulb. My first harvest turned out to be surprisingly good quality and I was quick to give credit to the expensive light. My yield was low, but that was because I was still trying to figure out the correct nutrient mix and wasn’t using proper pruning techniques. Now that I have a few years of growing canabis experience I can say for sure that these lights will produce wonderful buds if you know what you are doing. Start growing canabis now and as young as you can, I can only imagine the quality of medicine you and I could be producing 20 years down the road.