Jay Brown - Growing Marijuana Indoors

If you are growing pot in a basement with a concrete floor, just clean it and paint it white. It can be repainted gray or white or any color you prefer when you close down your pot-growing operation. If the floor is wood, put down a layer of heavy-duty plastic (available at hydroponics, hardware or carpet stores) over it. If you can’t find one piece of plastic large enough, glue two or more pieces together and overlap them on the floor. Make sure the edges of the plastic are stapled a few inches above the floor at about baseboard height so that any water spills won’t seep through the plastic onto the wood floor. As long as no water ever sits on the floor and stains it, a wood floor can be resanded and finished to look new whenever you want.

If you are growing pot on laminate wood floors or carpeted floors, put down a layer of plastic as previously indicated. Then, as if laying a floor, carefully place half-inch plywood panels over the plastic-covered carpet, cutting the plywood as necessary for a perfect fit. Use marine-grade plywood and fill any cracks or holes with wood filler. Fiberglass tape and resin can be used to seal the edges of the plywood to the wall and where two or more pieces of plywood butt together. When you have completed installation of the plywood, lay down another layer of heavy-duty plastic, making sure that the edges are stapled above the baseboard height. Growing pot on a carpeted floor is less than ideal, but it can be done.

I once saw an entire house (rented, of course) covered with wall-to-wall carpet, and the tenant was growing marijuana plants in every room. When it came time to close down the operation and move out, the plastic and plywood were removed from the walls and floors, and the carpets were shampooed and looked as good as new once the pile was vacuumed straight again.

Even with these precautions, you must be very careful with watering and moisture buildup. Use deep trays under your pots so that if you misjudge and overwater the plants, the trays will hold the overflow. Use a wet/dry shop vacuum to remove excess water from the plant trays and to immediately clean up any spills on the floors.

If there are windows in the grow room, they must be closed off so that your garden remains a secret from the outside world. A simple way to accomplish this privacy is to hang a pair of sheer curtains in the window and then screw a slightly larger plywood sheet (painted black on the window-facing surface) over the interior wall surrounding the window. This will block out all light from the grow room while presenting a normal appearance outside. If you want to get tricky, you can place a small lightbulb in the window that turns on and off by a timer to give the appearance of a lived-in room. If there is no other place to vent your room, a sliding window can be left open a few inches and a vent fan installed over a 5” hole cut into the plywood covering the window. But there are better ways of venting a grow room, which I’ll explain later in detail.

Like the gasoline that makes a car go fast, light makes cannabis grow fast. The most common lighting systems for growing cannabis indoors are 1,000-watt metal halide and 1,000-watt high-pressure sodium lamps. The former is the best for vegetative growth, while the latter is best for bud growth when a plant is blooming. These are the most powerful lighting systems available, and for larger operations of eight plants or more they grow the best cannabis. For smaller areas, such as closets, a 400-watt metal halide or sodium system is preferred because it produces less heat in a confined space than a 1,000-watt system. A 1,000-watt lighting system is best suited to a 10’ × 10’ or larger room and requires more aggressive temperature control with vented lamp hoods, air conditioners, or swamp coolers. A 600-watt halide system is also available and is reported to perform well in both the budding and vegetative stages of plant growth. But 600 watts is a little high for closet use and little small for budding plants in a larger room, so I have never had the need to really try one out.

LED systems are emerging as the new generation of lighting systems. These lighting systems offer as much brightness as conventional halide or sodium systems in light spectrums that are perfect for plants but look purple to the naked eye. LED systems offer this bright light without the electrical draw and heat buildup of halide or sodium lamps. The main problem with LED lights today is cost. They are very expensive, at about three times the cost of equivalent halide or sodium systems. LED systems have been found to work well for vegetative growing, for which they are pretty much as effective as conventional systems. However, they do not compare favorably with halide or sodium lights when it comes to flowering plants. So forget about LEDs for plants in bloom — for now.

If you’re budgeting for electricity use, in British Columbia the approximate electrical costs for running an indoor grow-room setup with one 1,000-watt hi-pressure sodium lighting system (for budding plants) and one 400-watt halide lighting system (for vegetating plants) including all related growing equipment (such as fans and pumps and timers, but not including a room air conditioner) is about $100 per month. These costs may vary depending on location and may increase with additional lights or equipment.

Lighting systems can be purchased from any hydroponics store and should include ballasts, lamps, ballast boxes, lamp hoods, and wall plugs. All lights should be hung on chains with S-hooks for adjusting the height of the lights up or down in the grow room, and lamps should be kept approximately 1’ to 2’ above the plants, although they can be a few inches closer when using vented hoods. Run electrical cords along the ceiling, supporting the cord with swag hooks. Ballasts should be raised off the ground on concrete blocks to prevent damage from accidental water spills, and should be enclosed in a vented metal ballast box for safety reasons. You don’t need an electrician to assemble this system, as the entire lighting setup can be provided by the hydroponics store ready to go. All you have to do is hook the hooded lamp to a ceiling hook, place the ballast box on a concrete block, and plug the wall plug into an outlet or a heavy-duty timer.

If anything ever goes wrong with this system, check timers first, then try changing the lightbulbs. In fact, you should change your lightbulbs every six months without fail. If you don’t change your bulbs every six months, your plants will grow more slowly and become wispy and unhealthy. Wait until a halide or high-pressure sodium lightbulb has cooled down before attempting to change it, and change all of your lightbulbs at the same time — that way you won’t forget any. If changing the lightbulb doesn’t solve your lighting problem, simply unplug the cord, unhook the light fixture from the ceiling hooks, and take the setup (ballast, wiring, lightbulb, and hood reflector) back to the hydroponics store or to a licensed electrician to be fixed. Do not open the ballast box or touch or prod it, for it is made to deliver high voltage.

Some growers use light movers, which are either tracked or rotating systems that move lights around the room. The idea is that a moving light system will cover more area since plants can take in only a certain amount of light per hour. The difference that light movers make is slight, and they are completely unnecessary for a small garden (under 10’ × 10’).

Figure 1: Choosing a Lighting System