Why use a grow light?
All plants require light to grow. In cases where you cannot use the sun or there is not enough sunlight, a "grow-light" makes for an ideal addition to your grow. Grow-lights are artificial light sources that are designed to provide a source of light that the plant can use. The range of light that a plant uses is known as photosynthetic active radiation (PAR). Grow-lights are also used to increase particular desirable traits in plants and benefit different stages of growth. This is done by manipulating the amount of light the plant is exposed to, i.e the photo-period. This is easily done by connecting your grow-light to a timer.
How is light measured and how much light does a cannabis plant need?
Light is measured in two ways: spectrum and energy and the two are directly related to each other. In order to measure how much energy a light produces, we use a special sensor that translates light into an energy reading in μmol or "micro-moles". This measurement is then translated into a photon flux density reading, i.e how many photons are being emitted from the light source. The more photons being delivered to the plant, the more photosynthesis it can undergo. Photons are measured in ppf and ppfd, with the former being the amount of photons the light source emits and the latter how many photons are delivered in a period of time. Plants use particular colours of light to best complete different processes. This means that the light must produce enough "energy" or photons and these photons must also be in the correct colour to induce photosynthesis.
Cannabis requires higher amounts of light than other plants, especially when in the flowering stage. The ideal amount of light for early stage growth ranges from 200-600µmol and flowering growth between 600-1200µmol. The more light provided, the more nutrients and CO2 the plant will require and the more it will grow correctly.
Is there an optimal cannabis grow light spectrum?
There are still many unknowns when it comes to the "best" light spectrum. However, no matter how powerful the light may be, if the spectrum is not correct, the plant may not grow as desired. The easiest bad example of this would be an all green light. No matter how strong the light may be, the plant cannot use green light for photosynthesis and cannot grow. Early research suggested that the most efficient wavelengths of the light spectrum for photosynthesis are red and blue. This caused many grow-light producers to focus on only these wavelengths. Modern light producers have however identified that a broad spectrum of light is far better for overall plant growth.
Cannabis Grow Lights Buyers Guide
From LED and fluorescent to HID, there are different grow-light options for different applications and preferences. Light emitting diode (LED) lights are the latest technology in grow-lights, using semi-conductors to produce light. These are assembled fixtures that need only be mounted and plugged in. High intensity discharge (HID) are bulbs that produce light via a chemical reaction in the bulb when ignited.
These bulbs include High Pressure Sodium (HPS), Metal-Halide (MH) and Ceramic Metal-Halide (CMH). HID lamps require a transformer or "ballast" to operate. These lights should be housed correctly in a reflector. Fluorescent lamps also use a chemical reaction to produce light and are usually in the form of large "energy saving bulbs" or CFLs. These lamps can be installed like regular household bulbs and merely need to be wired safely.
The dank, the sad and the hot of cannabis grow lights
The industry standard in grow lights, HID bulbs deliver exceptional and consistent results. These bulbs are ideal for all stages of plant growth and are very easy to purchase. A good reflective hood and additional grow area cooling are essential for best results.
Pros: High intensity light, easily replaced, easily mastered.
Cons: Heat output, electricity consumption, bulbs can be hazardous if broken.
Ideal use: Greenhouses, commercial setups, larger home grows.
Fluorescent options run very cool and can be placed very close to plants. Making them ideal for seedlings and young clones. They however lack good light penetration and if used on there own could lead to tall plants with fluffy buds.
Pros: Cheap, easy to install, low electricity consumption
Cons: Low amounts of light produced, do not run as cool as LEDs, short lifespan
Ideal use: Propagation/low-light requirements, small cabinet or hobby grows
The future of grow lights has arrived due to the recent innovations in LED technology. Fully optimized colour spectrums, 50000+ hour peak operating life and ergonomic design make LEDs the first choice for serious growers. Prices are however still a bit steep, yet this investment is soon recovered thanks to their energy efficiency and lower operating temperatures.
Pros: Long-lasting, low heat profile, high light output
Cons: Expensive, individual parts are harder to replace, fixtures have a finite lifespan
Ideal use: Home grows, high-tech setups, commercial applications
Each type of light has its' own benefits. LED lights require less electricity than HID bulbs and can produce as much light or more per watt. However LED lights are a lot more expensive than their HID counterpart. Fluorescent lights may not consume as much electricity as a HID or produce as much heat, but therefore lack punching power. Thus, your application is vital to your choice in grow-light.
Ceramic Metal-Halide vs HPS
Ceramic Metal-Halide bulbs deserve a special mention when it comes to grow-lights. These are HID fixtures that are able to produce the same amount of light as a HPS, but at a fraction of the heat and in a better spectrum. This is especially favourable to cannabis growers as the HPS bulb has been the lamp of choice for most cannabis growers over the years. With a CMH fixture, you are able to provide as much intensity as an HPS lamp, while making use of an improved spectrum to induce greater secondary metabolic processes- think oils, aromas and flavours. Aka Terps! To add insult to injury, a CMH light can also be used in smaller grows as they range in size from 315w to 930w. Ultimately this means that the HPS bulb's future is slowly growing dimmer.
Don't grow blind!
As much as we all delight at high light readings and blindingly bright cannabis grow lights, it is vital to take care of one of your most precious tools... your eyes.
Method Seven makes the highest quality lenses to protect your eyes from high powered lights. Whether you are using HPS, LED or simply outside, Method Seven has the right product for your needs. The truly revolutionary aspect of these lenses are their ability to balance the colour under your grow-light. This means that when using the appropriate pair of glasses, the colour of your grow-light won't affect how you see your plants. This means you will be able to spot problems and pests faster, while also putting safety first.
Invest in the right light
All in all, you need to decide which light suits your needs. Between budget, area and expectations, you will need to choose a light to suit your particular environment. Don't buy the best light you can, while ignoring other aspects of the grow. Balance is key! Make sure the product you choose provides enough light for your area while maintaining an ideal environment.
Need a little help making up your mind about the best grow light for you? Please contact our grow pros for some top shelf advice.