part0011

In this section, we’ll tackle the basics of lighting and the different types of lights available, how to determine the right amount of light for your space, and the equipment you’ll need to brighten up your space and give life to your plants. The amount of light available to your babies is often the number one factor dictating the success of their growth and bud development.

Your choice of lighting setup will be one of the foundational aspects of your indoor growing operation and can limit you accordingly. Lights are typically the single largest expense of a grow room and, all things being equal, have the greatest impact on your ability to produce fully developed marijuana as quickly as possible. They also determine the frequency of your harvests. Lighting is one thing you should enhance to whatever level your budget will allow. Although lights come in many different types and configurations, in general they share three features in common: the ballast, the lamp, and the reflector. Let’s take a closer look at each.

A ballast is a device that regulates electrical current to provide a steady output of light at a given intensity. Unless you purchase separate components, most light setups will include an appropriate ballast. The ballast is the workhorse of the broader light setup, and although high-quality ballasts are costly, you can’t run high-quality lamps without them. Check out the illustration of the complete grow light kit here —the ballast is integrated into the unit and is not visible. Fluorescent bulbs have relatively small ballasts, while high-intensity discharge (HID) lamps require bulkier ballasts typically containing a fan and additional capacitors. Light-Emitting Diode (LED) lights and Compact Fluorescent Lights (CFLs) require no ballast at all.

Without taking you on a bad trip into the physics of light, we can tell you that the cannabis plant responds better to blue light in the 400 to 500 nm (nanometer) range for vegetative growth and to red light in the 620 to 780 nm range for flowering and bud development. Some growers will choose to have two sets of lights, each one producing one of these ideal ranges. Most indoor grows with a perpetual harvest will have a smaller area set aside for vegetative-state plants and the bulk of the space devoted to the larger flowering plants. This, however, can sometimes present challenges when it comes to keeping light out of the flowering plants during the flowering stage’s 12-hour dark period. Fluorescent lights are the least costly of the options and may be suitable for vegetative growth but often don’t contain enough of the red spectrum to produce decent buds. Historically, LEDs were found to produce decent vegetative growth but suffered when it came to bud development, but today technological advances have resulted in increased acceptance of the use of LEDs for all stages of the plant’s life cycle. There are many varieties of lamps with different costs and benefits; we’ll look more closely at LED, HID, and other types of lamps in the next section, the Light Source.

Once you’ve chosen a lamp and appropriate ballast to power it, the next thing you’ll need is a reflector. A lamp by itself scatters light in all directions. The reflector concentrates the light from the lamp so your plants get the bulk of the light produced. Reflectors usually have angular surfaces to reflect and deflect the light onto a focal point. They also contain the socket for your chosen lamp, a cord to connect to a ballast, and installation hardware. Many light setups are suspended on a pulley system so the light can be raised as the plants grow and lowered when beginning a new crop.

Your light source and the quality of light it produces are crucial for your indoor grow space. Outdoor spaces have to rely on the sun, so a major benefit of an indoor grow space is being able to choose your own lighting source. A huge variety of lighting types exist, which can be overwhelming. Lights will most likely be your biggest expenditure, so do your research online and ask other growers. Consider how much you can/want to invest, and get the best possible lighting setup you can. You’ll want to strike a balance between your budget, the type of light(s) you choose, and their intensity.

LEDs are gaining favor due to their affordability and reliability. Like fluorescents, LEDs are energy efficient and give off little heat. This can be good or bad depending on the outdoor climate your indoor grow room is located in. If you choose to go with LEDs, make sure they have switchable vegetative and flowering growing spectrums or cover a light spectrum suitable to both growing stages.

High-intensity discharge (HID) lamps include metal halide (MH), high-pressure sodium (HPS), and dual spectrum (DS) varieties. They make up a family of lights with high performance and intensity for a moderate cost. Before the recent advances in and new applications of LEDs, HID lighting was the pinnacle for growers. It and is still used in the majority of indoor grows today.

Metal Halide (MH) lights emit light in the cooler blue part of the spectrum, so they are ideal for the earlier stage of vegetative growth, producing stocky plants with strong stems, branches, and leaves. The downside to MH lights is that they should not be used by themselves as they don’t emit enough red spectrum light to produce flowers and buds. Those choosing to go the MH route will need an additional light or lamp for the flowering stage. MH lights often have shorter lives than many other types of bulbs, requiring more frequent replacement and thus increasing costs.

When MH lamps are used, HPS lamps often accompany them to provide the light from the warmer red part of the spectrum needed for flowering and the development of buds. HPS lights are energy vacuums and are the most expensive type of light to operate. Besides light, they also give off intense heat, so the surrounding air needs to be cooled or vented. Because of this, HPS lights may not be ideal for extra-small spaces where the heat from the lights can constitute a fire hazard. They also have a tendency to lose performance over their lifetimes, so factor in replacement costs as you plan your budget.

Dual spectrum HIDs combine both the blue and red spectrums in a single lamp that can be used continuously in your grow, regardless of which stage of growth your plants are in, so you don’t have to switch out bulbs when your plants transition from vegetative to flowering states. Though typically not as expensive as MH and HPS lamps purchased together, dual spectrum lamps can still be costly.

Some growers choose to supplement the primary lighting equipment in their grow space to add light or to change the light spectrum. Plasma-based lamps are a recent development and boast the full color spectrum, making them a good—but costly—option for a small indoor grow. Plasmas don’t quite meet the light intensity levels seen from MH or HPS lights but put out heat on a scale similar to HPS lights.

COST-EFFECTIVE LIGHTING

The goal of your light source is to mimic the sun and the natural light your plants would experience if they lived outdoors. Blue lighting represents the light spectrum seen in spring and summer, when plants use their energy to increase their biomass, and red lighting represents the spectrum seen in fall, when plants shift gears into focusing on their progeny through the flowering (reproductive) process. The amount of light you need inside your indoor grow is dictated by how many plants you are growing. Too much light can actually impede growth. You won’t win any awards for your grow light being visible from outer space.

As previously mentioned, your lighting system will most likely be the biggest cost of your growing operation, so make sure it’s an efficient use of your dollars and that light is going into the development of buds and not being wasted. Pruning and plant training can be major allies in this respect, giving you more bud per lumen of light. Here are a few tips to save on energy for lighting:

• Run your lights at night to help with maintaining climate control in the cooler nights.

• Inspect your plants with a head lamp instead of turning on your complete lighting apparatus.

• Use reflective materials on walls and partitions to maximize reflectivity and allow plants to capture all available lumens.

• Keep your lights as close to your plants as possible to maximize the lights’ benefit and encourage faster development.

• Change lamps on an appropriate schedule to avoid the lower light intensities common in aging lamps.

Light provides the sustenance marijuana plants need to grow stems, leaves, branches, and ultimately buds. Light is as critical to plants as food is to humans, and its effects are just as pronounced. The right amount of light will make happy, healthy plants that will grow into substantial harvests. Too much light can cause light burn and bleaching. It can also lead to nutrient toxicities, because as light is increased, so is a plant’s water/nutrient uptake. Plants don’t discriminate as to what their roots do or do not take in. If fertilizers or nutrients are present in the soil or nutrient media, too much light will make a plant take them in faster than it can use or relieve itself of those compounds.

Some rookie growers mistakenly use the full volume of their enclosure (length multiplied by width multiplied by height) when calculating the amount of light needed for their indoor grow. Although the volume, measured in cubic feet, is important when looking at ventilation, airflow, and circulation, the amount of light you need for your grow space isn’t related to the volume of the space. Regardless of your choice of tent, closet, or room, you’ll instead want to look at the area taken up by the canopy of your plants to determine your lighting needs. If you have a space that is four feet by four feet but your plants only take up three feet by three feet, you would base your lighting on the latter. As a rule of thumb, target 20 to 50 watts per square foot. Based on this, a canopy that is three feet by three feet would require a light source in the 180-to-450-watt range.

Lumens are a measurement of light output and intensity. Lux is a measure of how much light is received by a surface, such as the leaves of your plant. An inexpensive lux meter can be a great tool in your arsenal to figure out exactly how much light your plants are getting. Your marijuana plants have different light-intensity needs over the course of their life cycle, as shown in this table:

In general, position your lights as close to your plant tops as you can without causing any ill effects. Fluorescents and LEDs will generally allow for the closest positioning to plants—as little as a few inches away. The greater the output of light, the farther away you’ll need to position your light relative to the plants. When it comes to HIDs, as a baseline, you’ll want the tops of your plants no closer than 16 inches to a 1,000-watt unit and no closer than 10 inches to a 250-watt unit.

POWER REQUIREMENTS

To determine how much energy your lights will use, look at how many amps your lighting and other devices are rated for. Most standard outlets are on a 15-amp breaker and can support up to 1,400 watts. This could accommodate two 600-watt lights and a 200-watt fan, which is a lot for the size of most spaces we’ve been talking about. The key is to know how many outlets you have and to evenly distribute your power needs across multiple outlets. If you have any questions or start tripping breakers, it’s always best to consult a licensed electrician.

FOR AVERAGE ENERGY COST PER DAY IN A SPECIFIC GROWTH STAGE, USE THE FOLLOWING FORMULA:

(Wattage of device/1,000) x (Number of hours used in growth stage per day) x (Cost per kWh)

For example, if you have a 600-watt light you run for 20 hours per day while in the vegetative stage and 12 hours per day during flowering, and the cost per kWh from your electricity provider is $0.15:

(600 watts/1,000) x (20 hrs/day) x ($0.15/kWh) = $1.80 per day for vegetative stage

(600 watts/1,000) x (12 hrs/day) x ($0.15/kWh) = $1.08 per day for flowering stage

FOR AVERAGE ENERGY COST PER DAY ACROSS THE ENTIRE GROW CYCLE, USE THE FOLLOWING FORMULA:

((Cost per day vegetative x number of days in vegetative stage) + (Cost per day flowering x number of days in flowering stage)) / Total number of days in cultivation

So, using the same example and assuming the typical 21 days of vegetative growth and 42 days in the flowering stage:

(($1.80/day x 21 days) + ($1.08/day x 42 days)) / 63 days = $1.32 per day for the entire grow process (and $83.16 total for one full grow cycle)

Good yields range from 0.5 to 1.0 grams of useable marijuana for every watt of lighting. In a perfect world, a 600-watt light would yield 600 grams, or roughly 21 ounces, of marijuana. That’s a lot of weed for $83 in electricity costs.

Any intrusion of light in what should be a period of darkness will confuse plants. Confused plants may turn hermaphroditic, a state in which they exhibit the sex traits of both male and female plants. The job of male plant parts is to pollinate female plants, which in turn produce seeds. But just like undetected males, hermies can ruin your crop in a heartbeat because most indoor growers are in it for sinsemilla, or high-quality, seedless buds. For this reason, indoor growers may purchase exclusively feminized seeds and/or perform periodic inspections and cull any plants exhibiting male traits. We’ll talk about sexing of marijuana plants more in Step 9: The Care .

There is no truly technical way to test for light leaks in a small grow operation. Before starting cultivation in your new grow space, turn off all lights and equipment within the grow area and turn on any lights just outside the grow area, using portable lamps if necessary. You need a light source outside the grow area to test if light is making its way in. If your grow area is big enough, have a friend seal you inside it to replicate what plants will see in the dark period. Make a note of or use tape to tag any areas where light is coming in. Pay special attention around zippers, flaps, doors, seams, and penetrations into your growing space.

Repair or cover the identified areas in a way that doesn’t compromise access. If mending the interior, think about using reflective or bright white tape to maintain the level of lighting intended versus, for example, black electrical tape that will absorb much of the light instead. Once modifications are complete, verify they were effective and no light is entering the growing space before you proceed with cultivation. If light interruption occurs during the grow cycle but is relatively short during the vegetative stage, you can probably get away with returning to the proper light schedule and monitoring for hermaphrodites (see Hermaphroditic Plants ). If the light interruption was relatively long (more than two hours) during flowering, then plants may revert to the vegetative phase, so you’ll want to identify any hermies ASAP and stay vigilant in case more appear. Plants that are stressed by any of these events, even if salvageable, will often produce significantly lower yields.

TAKEAWAYS & EQUIPMENT LIST

Look at you go! Another chapter under your belt. You’ll be growing like an OG in no time. The section you just made it through is one of the drier parts of the book, so if you’re still awake, great work.

In Step 3: The Light, we were exposed to the ins and outs of lighting a personal, indoor grow space, including:

• The basic components of grow lights: ballast, lamp, and reflector

• Different varieties of lamps and their pros and cons

• Tips to reduce energy consumption

• The right amount and quality of light for your operation

• The importance of lightproofing your growing space in order to maintain dark periods

SHOPPING LIST FOR LIGHTING YOUR GROW SPACE

Apparatus to suspend and raise or lower light assembly as needed

Head lamp to wear while inspecting and monitoring plants

Lux meter to measure light received by plants

Reflective or white tape

Self-contained grow light of appropriate wattage or correctly sized ballast, lamp, and reflector that accommodate one another

Tape measure to measure canopy and plants’ distance from lights

Let’s continue on with our green journey. In Step 4: The Environment, we’ll talk in detail about monitoring and managing air supply so your babies will not just survive but thrive.

GROWTH STAGE	OPTIMAL LUX RANGE
Seedling	4,000 to 7,000
Vegetative	10,000 to 50,000
Flowering	35,000 to 75,000