budding plants. The “red” end of the light spectrum, which HPS lamps provide in abundance, promotes flower production, which means fatter, denser buds. HPS lights also last longer and stay stronger than MH lamps, with less maintenance required.
A souped-up version of the fluorescents found in many offices, compact fluorescent (CF) lamps create light by passing electricity through gaseous vapor. Ideally suited for closet gardens, these incredibly efficient lamps produce sufficient lumens to support vegetative growth with only a tiny fraction of the energy consumption and heat generated by MH and HPS lights. This means CF lights can be placed far closer to the plants, greatly reducing the need to ventilate and/or cool the growroom. Ideal for growers with a limited space or on a budget, CF lamps can also be used for flowering plants, but will prove far less productive in terms of yield than MH or HPS lights.
Light-emitting diodes, or LED lights for short, emerged recently as an eco-friendly alternative to high-intensity discharge (HID) lighting. Although they use much less energy, the costs of the new units are still high and the technology is still in a developmental phase. Look for prices to go down and lumens to increase in the future—but for now, these new systems aren’t outperforming CF or HID lights in the growrooms we’ve seen.
High-intensity grow lights, particularly MH and HPS systems, create a large amount of heat and excess energy while operating. Ballasts limit the amount of current sent to these lamps, preventing heat from building up to unsupportable levels and burning out the bulb. Always make sure that your ballasts are in good working order and have been designed to operate with the particular lamps and bulbs you’re using. Different manufacturers and specs can make this a confusing process, so ask for professional help at the hydro store and spend a little extra money to acquire high-quality ballasts.
Always use a bulb that’s designed to work with both your lamp and your ballast. Improperly matched equipment will be inefficient at best and dangerous at worst, so pay careful attention to this when buying your gear. Bulbs come in a variety of sizes that may be used for growing cannabis (up to 1,500 watts), but bulbs in the 400-to 600-watt range are most efficient, particularly in smaller rooms. Remember, giving your plants more light than they either need or can use will not make them grow any bigger or faster.
Keep your bulbs immaculately clean, as dust on the surface can significantly reduce output, and never touch them directly with your hands, as your fingers will leave behind an oily film that blocks light meant for your plants. Bulbs will slowly lose their brilliance over time, so check them often with your light meter.
No matter what type of lamp or what size bulb you use, the name of the game is getting as much light to your plants as possible. Installing a reflective hood over your lamp will take otherwise wasted lumens and reflect them back down into your garden. Look for a reflective hood that spreads light evenly across the growroom, even if that means spending a little extra money to get a high-quality piece of equipment that’s bound to save you lots more money down the road in increased efficiency and bigger yields.
The air within the garden should be circulating sufficiently to gently flutter the leaves on your plants, which helps to promote the healthy exchange of oxygen for carbon dioxide that allows your plants to “breathe” and contributes to photosynthesis. Common types of oscillating desk fans or their equivalent should be placed strategically throughout the room to ensure an even circulation of air.
All of the air in your growroom should be completely ventilated every five minutes; otherwise, heat and humidity will build up to levels that stunt plant development. Removing stale air from your growroom starts with installing an exhaust fan as closely as possible to your ventilation opening, which can be either an existing window, airshaft or chimney, or something that you construct yourself. The less ducting there is connecting your fan to the opening, and the fewer turns that ducting makes, the more efficiently your system will operate. Also, think