You have to create an excellent climate for your marijuana plants for them to grow. Outdoors, you’re unable to influence the hours of sunlight your plants get every day. You also can’t do anything about the temperature they’re exposed to. But if you’re growing indoors, you can control everything.
And fortunately, there’s a lot of measuring and control equipment available to make our lives a lot easier. In this chapter I’ll tell you about the most important tools you need, and what they do.
The more light your plants get, the better they’ll grow. The best lights are HPS lights. I always advise people to use 600 watt for every 12 square feet during flowering. When your plants are still in the growing stage, it’s better to use a 400 watt MH light per 12 square feet. If you don’t want to spend as much money on lighting, you can also grow under fluorescent lights.
Light is emitted in all directions. By using a reflector you can prevent the loss of light that would otherwise be shone at the ceiling and the walls, because the reflector makes sure all the light is being shone downwards.
Since 600 watt lamps use quite a lot of electricity, it’s best to put a ballast in between. A ballast ensures a high starting voltage and limits the energy use after starting up. There are currently dimmable ballasts you can connect a 400 watt and 600 watt bulbs to. You can also buy a complete set at Amazon with bulb, reflector and ballast to save money
The lights have to be plugged into a time switch, so we can influence the light cycle of the plants. A time switch allows us to set the time the lights should turn on and off. Time switches come for 1, 2, 4 or 8 lights. Don’t connect more than 4 lights to one circuit.
You need an air extractor to get rid of the warm air the lights create. It’s best to buy an extractor in an insulated box and hang this to the ceiling. This is because they can get quite noisy. In addition to getting rid of warm air, the exhaust can also create negative air pressure, so no marijuana smell can escape the room unless it’s through the exhaust. You have to attach a carbon filter to the extractor to filter the air.
Use 440 CFM of extraction for each 600 watt lamp. So if you have 5 lamps, use an exhaust with a capacity of 2200 CFM. By doing so you will have enough capacity to also get rid of the warm air during hot summer days.
This filter neutralizes the strong smell the marijuana plants spread, and can be attached to the air extractor so you can safely get rid of the warm air by blowing it outwards. Don’t use a carbon filter for more than 6 harvests, and know that a high humidity (above 80%) can cause the filter to lose its ability to neutralize scents.
If you want more air that’s rich in CO2 or you want to additionally cool the room with cold air, you could attach a fan to the hole for fresh air, to blow air into the room. Always choose half of the capacity of your extractor, so if you have a 440 CFM extractor, pick a fan with a capacity of 240. If you don’t do this, you’ll create positive air pressure, and air will escape the room.
You can use a speed controller to determine the settings of the air extractor. More air needs to be extracted when the lights are on than when they’re off. A controller with thermostat allows you to always have the extractors work at 25% capacity until the temperature rises above for instance 77 degrees. The extractor will then work at 75% capacity until the temperature drops below 77 degrees again. You can perfectly manage the temperature in your growing room this way.
Place a rotating fan next to the plants and aim it between the light and the plant. This will make sure the hot and cold air is mixed to create a good climate. This will also prevent ‘dead’ angles where fungi and diseases have better chances of developing.
You measure the temperature in your grow room with a thermometer, either a digital or analogue one. You can buy one for a couple of bucks. I always use a digital thermometer/hygrometer with a memory feature, so I tell see what the highest and lowest temperatures have been. It’s also useful to get one with a temperature sensor on a wire, so you can hang the display outside the grow room. This allows you to check the temperature when the lights are off.
A hygrometer measures the humidity of the grow room. You can once again buy a digital or analogue one. A cheaper one will cost a few bucks, but you can buy a digital one with memory feature for $12. I always use a combimeter that measures the temperature and humidity both inside and outside the grow room.
You need a nice, big tank to make a good nutrient solution. About 10 gallon for each 600 watt lamp. You often need to add some more warm or cold water to achieve the right temperature, and a big tank allows you to store the nutrient solution for a couple of days.
You have to get an EC meter to measure the amount of nutrients (minerals) in the water. You could also stick to the label on the bottle of nutrients, but it’s always better to measure it yourself. This meter also measures the pH and temperature.
You also need a pH meter, because you need to lower the pH of the water after adding nutrients. You can get a pH meter for 10 bucks or so, but if you spend a little more, it will also be able to measure the EC and temperature of the water.
Depending on the size of your growing operations, you can choose a watering can or a pump to provide your plants with water. Hydro growers must have a pomp (connected to a time switch). If you grow on soil, I advise you to start using a pump from 3 x 600 watt lights and more. A watering can will do fine if you have 1 or 2 lights.