The $1,000 Growroom

Allow me to first throw out a few disclaimers. Our chief concern here in the Cultivation Department, as always, is the safety and well-being of our readers and growers, as well as the families and neighbors of said growers. To grow marijuana safely is sometimes contradictory to doing it inexpensively. Cutting corners can be easier and may save time and money, but remember this: It’s one thing to get busted growing weed, but it’s an entirely different thing to get busted growing weed because you burned down your house, or an entire apartment building, and people suffered or were injured because of you. This is what we want to avoid. Growing quality cannabis should be a safe and soothing experience, not the contrary.

So in order to protect yourself and those close to you, yet at the same time be able to grow excellent ganja in your own home (on a budget), there are only three words you need to know: Keep it simple. Trying to do too much can get costly as well as dangerous and is usually not even necessary. So take a step back and look at your space, and together we can create an inexpensive and safe (but still very effective) method for you to grow your own right in your very own home.

Let’s approach this logically. The basic tenets of plant biology, or gardening in general, begin with four basic elements: water, light, gases and solids. To start, all four of these elements contribute in some way to photosynthesis—the plant’s natural process for manufacturing sugars, or food, for it to live and grow. Water and light are self-explanatory, but the other two require brief explanations. Gases, such as CO₂ and oxygen, are integral to the process of photosynthesis. Solids, such nutrients or fertilizers, are minerals and vitamins that also aid in photosynthesis, food transfer within the plant, cellular growth and disease prevention.

A curious fact that many growers don’t often realize is that CO₂ was first introduced into indoor growrooms to treat the problem of heat. With rising growroom temperatures due to high-powered lamps and poor ventilation (two areas that we’ll cover in the third section of this article), many indoor growers began using CO₂ to open the plants’ stomata, which close up when the plants overheat, thus preventing photosynthesis. By keeping your growroom simple and using the right lighting and ventilation, you can avoid this problem and eliminate almost any need for CO₂. And that’s just one example of the many ways you can begin saving money while setting up a top-notch growroom right now!

When it comes to gases and solids, it’s not always necessary to artificially infuse these elements into your growroom. Ambient CO₂ levels in our natural atmosphere are high enough for sustaining healthy, happy marijuana gardens. Additionally, oxygen—which is only absorbed by a plant through its root system—is also readily available in plentiful amounts in the air surrounding us. The key to ensuring ample oxygen uptake at the root level lies in using an airy grow medium that allows for good air penetration.

Nutrients and fertilizers take on a slightly different function than do CO₂ and oxygen. While some grow mediums, like outdoor soils or high-quality soilless mixes, contain some amounts of nutrients and minerals, it is sometimes a good idea to supplement your garden with mild amounts of nutrients, especially in the later phases of growth and flowering. If you’re using a synthetic grow medium such as rockwool or expanded clay, you will most certainly need nutrient additives. Still, remember to keep it simple.

Whether you’re growing hydroponically or using a more organic method, don’t go nuts buying the most expensive nutrients on the market or something that has 15 different parts and an insane mixing and feeding schedule. There are plenty of high-quality, inexpensive two- or three-part feeds that work very well. Reputable brands such as Botanicare or General Hydroponics make relatively inexpensive nutrients that are easy to use. All you really need is a two-part nutrient solution: one for use during the vegetative phase (labeled “Grow” on most bottles) and one for use during the flowering phase (labeled “Bloom”). Nutrients are always labeled in the same order, N-P-K: nitrogen (N), phosphorous (P) and potassium (K). Nutrient fertilizers are formulated to include these and other major nutrients (known as macronutrients) as well as the essential micronutrients that your plants will need during each phase of growth.

And just like that, you can eliminate the need to add tanks of CO₂, regulators and timers, air pumps, spaghetti lines to the root zones, dozens of bottles of nutrients, huge mixing buckets and all that other expensive gear that growers throw in their growrooms. Keeping it simple saves time and money and not only makes for happier plants, but also happier growers.

Build-Your-Own Price Sheet:

This is perhaps the most important section for your growroom, and the reason is twofold. First, lightning represents both the most expensive and the most dangerous aspect of your indoor grow op. And second, as mentioned earlier, lighting also presents one of the biggest hazards to your plants—heat.

Let’s begin with choosing the best lamp for your growroom. The first rule: No matter what size your space is or what system your garden utilizes, never buy a cheap or secondhand lamp. Growroom lights use a lot of electricity, and the wiring and ballasts that supply that electricity to the bulb is the difference in whether or not a fire can start in your growroom. Therefore, this is not the place to skimp on costs.

The next thing to focus on is your actual growroom size. High-intensity discharge (HID) lamps are sometimes too intense for a very small space. For spaces smaller than 4’ x 4’, you may consider using fluorescent bulbs, perhaps something on par with a bank of T5 or T8 fluorescents. These bulbs are inexpensive, use way less power, give off very little heat and provide excellent spectrum for plants—but they will yield less than HID lamps come harvest time.

If your space is slightly larger, or has more space for ample air circulation and ventilation, you can consider larger lamps. Metal halide (MH) and high-pressure sodium (HPS) bulbs are the most popular choices among growers, but if you’re going with only one fixture, HPS is the usual choice. Some ballasts allow growers to switch bulbs, using an MH during the vegetative (“grow”) cycle and HPS during the flowering (“bloom”) cycle. These bulbs usually range from 250 to 1,000 watts. Figure 1.1 shows the coverage areas for bulbs of various wattages.

Another important consideration when choosing your lamps is the type of ballast your lighting system will utilize. Today’s grower has two options: core and coil ballast (magnetic) or an electronic (digital) ballast. The newest and most efficient ballast on the market is the electronic ballast, but it’s also the most expensive. Choose a ballast that suits your budget—but again, it’s always best to buy a new unit that comes directly from the store or manufacturer with a warranty.

Depending on the size of your growroom and the bulb size you use, ventilation becomes increasingly important, as does general air circulation. Ventilation can be as simple as a small intake fan at the bottom of your space and an exhaust fan at the top of the room. Good air circulation can be achieved with another small oscillating fan situated on a table or wall mount near the top third of your canopy. Ventilation helps prevent heat from building up in the growroom, and the circulation helps keep the temperature down, as well as moving air past the leaves for better CO₂ absorption. 

Using HID lamps makes it essential that your room is properly ventilated. Some people choose to air-cool the bulb and reflector hood with inline fans and ducting, and even though this is a very good option, this method can get very pricey. To keep things inexpensive, install an air vent at the bottom of the room’s door and put a small floor fan inside the room to pull air in. To exhaust the room, find a spot to vent air out near the top of the room, where the heat will be accumulating. A small window might work, or you could cut a small hole in the top of a wall or door—and again, installing an air vent will also work very well. Affixing an exhaust fan to this vent or hole can be done by hanging the fan on chains from the ceiling or using a wall mount. In extreme situations where high vent holes might pose a problem, you can use flexible ducting attached to a floor-based fan. Hang the ductwork high in the room—preferably over your light—and work it down the wall to a fan that is blowing the hot air out of the room. Flexible ducting, chains, air vents and wall mounts are all relatively inexpensive items and can usually be found at your local hardware store or Home Depot.

Build-Your-OwnPrice Sheet:

            Dual (intake/exhaust) window fan: $20

            10” power intake floor fan: $30

            16” oscillating fan with stand: $30

400-watt MH/HPS system: $297
400-watt MH/HPS digital system: $290

            6” inline can-fan (440 cfm): $185

            6” flex duct, non-insulated (25’): $27