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5 Things You Should Know Before Buying LED Lights To Boost Bud Production

A cannabis plant under LED growing lights
August 03, 2020

Light-emitting diodes or LED grow lights are an increasingly popular lighting option in the marijuana cultivation scene. Many growers believe LEDs help produce higher-quality buds with more trichomes and better flavor. They may have started as a novelty, but LED lights have since gained a solid reputation as an effective means of boosting marijuana plant growth and bud production, while also saving you time and money.

LED lights are as dependable as traditional types of grow lights and have the added bonus of being more energy-efficient. They can mimic natural sunlight, producing the full spectrum required at all stages of your cannabis plants’ life cycle. Far from being too expensive to buy as they were a few years ago, high-quality LEDs are now more affordable than ever.

What Other Types of Grow Lights Can You Use Besides LEDs?

When it comes to lighting systems, LEDs are a widely-approved option. Nonetheless, some marijuana cultivators prefer other types of grow lights – CFLs, fluorescents, and high-intensity discharge lamps. Each have their pros and cons, and it’s better to be aware of them before you make your final decision.

CFL or Fluorescent Lights

Farmers and botanists have been using fluorescents for a very long time because the technology has been around for a very long time. It is still a popular choice for people who grow marijuana strains that are extremely sensitive to heat. You can position these lights very close to the plants, as little as 5 cm distance, without any adverse effects.

Depending on the number of cannabis plants, you could install several fluorescents to increase the wattage. To maximize their efficiency, you could also install reflectors on the interior walls of the grow room. One thing you should not do is to force them to produce all the optimal wavelengths necessary for the vegetative and flowering stages.

High-Intensity Discharge (HID) Lights

HIDs, initially used to illuminate large venues like stadiums and arenas, are powerful lights that have a good track record when it comes to marijuana cultivation.

One type of HID is the metal halide (MH) light. It emits a bluish glow that is ideal for the vegetative stage because it encourages plants to produce more foliage. At the same time, you can also use it for the flowering stage. MH lights are flexible, which is the reason they are popular with growers.

High-pressure sodium (HPS) vapor light is the other common HID light. It produces a dull pink glow that turns to orange when it warms up. This color is particularly suited for the flowering stage.

MH and HPS lights are usually used in conjunction to provide the full spectrum of colors required throughout the cannabis plant’s growth cycle. HID growers would have both MH and HPS, which means additional expenses. Furthermore, they produce plenty of heat; hence you will need other equipment like an air-conditioner to cool down the grow room.

5 Things You Should Know Before Buying a LED Grow Light

If you are thinking of switching to and buying grow LED lights, here are 5 tips to help you on your way to a bountiful yield of aromatic, potent buds.

  • Know the advantage of LED grow lights.
  • Be familiar with the different types of LED lights.
  • Calculate the wattage you need.
  • Position your LED lights properly.
  • Consider your plants’ light requirements during every growth stage.

I. What Are the Advantages of LED Grow Lights?

LED lights have many advantages compared to compact fluorescent bulbs or high-intensity discharge lights. Being efficient with energy use is one, another is producing less heat than HIDs. Let’s look at the reasons why you should choose LEDs for your growing operation.

1. More Energy-efficient

LED lights use less electricity and can save you money in the long run. LED consumes 40% less energy than HID, and 50% less than CFL. While it is true that high-end LEDs are more expensive to purchase, the initial investment is offset by your electric bill savings over time.

Furthermore, LED light fixtures have a longer lifespan than other types of lights. Therefore, there is no need to replace them as often. For example, an HID light lasts between 2,000 to 3,000 hours, but an LED will give you 50,000 to 60,000 hours. That’s a difference of almost 5 years!

2. Produce Less Heat

LED lights run cooler than HIDs, which means that you won’t have to buy an air-conditioning unit or evaporative cooler to lower the temperature in the grow room. If you are growing marijuana in a warmer climate, then LEDs make more sense.

On the flip side, if you live in a cooler climate, your grow room might get too cold because LED light fixtures do not contribute significant heat. An electric heater might be necessary. Nevertheless, the lower energy consumption of LEDs will make up for the cost of operating a heater.

3. Uses Less Space

An LED lamp uses far more energy efficient because it focuses light through a lens, unlike an HID light, which requires external reflectors. Moreover, since LEDs produce less heat, you can move the lights closer to your plants. The upshot is a greater light intensity for the plants, which results in higher yields.

4. Safer

LED bulbs do not emit polluting radiation, and therefore do not pose a health hazard. They don’t contain mercury like other lights, such as CFLs. They are also less of a fire risk due to lower heat output.

5. Reduce Your Watering Schedule

Because there is less heat in the grow room, there is less evaporation. Your potting soil will remain moist longer after watering, and you won’t have to water the plants as often.

A nutrient mix is usually added to the plants’ water, so less-frequent watering translates to less expenses for nutrients, too. Additionally, there is a lower risk of nutrient lockout due to the buildup of nutrients from chronic watering and feeding. A nutrient lockout can stunt your plants’ growth, and even kill them.

II. Be Familiar with the Types of LED Grow Lights

Before buying an LED grow light, you should know what’s available in the market. Three main types of LEDs can be used to grow marijuana. Each one has its pros and cons, and it is best to study them first to avoid mistakes and regrets later on. Choose the one that fits your needs and budget.

1. Standard or Purple LED

This type of LED fixture is the oldest, and it is still widely available. It comprises hundreds of single small or medium-wattage LEDs – about 3 to 5 watts for each one – spread out in a compact light fixture. Marijuana growers often call these purple lights because they emit a purple hue that comes from the mix of the individual red and blue LEDs.

Purple LEDs are cheaper to buy, and they are easy to find online. However, sometimes the quality is not up to par compared to other types of LED. Their light output is often lower, too, which can lead to lower yields. Some standard LEDs are being offered, including COB lights or UV LEDs on top of the red and blue, which can improve bud quality and yields.


The COB or “chip on board” LED bulb contains multiple tiny LEDs on a small chip. COBs produce a very bright white light, which is similar to sunlight’s natural spectrum. The intense light can easily penetrate the plant canopy, which results in higher yields.

COB LEDs are more expensive than purple lights, but they have a color spectrum optimal for healthy growth. Some manufacturers combine several COB bulbs into one light fixture, but individual bulbs are also available for greater customization. Most growers buy COBs with a spectrum that works for all marijuana growth stages, while others use separate bulbs for the vegetative and flowering stages.

3. Spread-Style LED

The spread-style LED is a common sight in commercial greenhouses. Each fixture is made up of many low or medium-watt LEDs that are distributed over a large area. Rack-style LEDs are set on a flat sheet or board, while spider-style LEDs are placed on arms instead of a solid panel.

This type of configuration is the most cost-efficient by providing the most amount of light for the wattage used. However, the purchase price could get a bit high in comparison to the other types.

III. Calculate the Wattage You Need

Although it may sound complicated, finding out the size of the LED lights you will need for your grow room is actually very straightforward. Just refer to the table below.

Number of Plants Area in Square Feet Recommended Wattage
1 1 32
2 2 64
4 4 128
6 6 192
8 8 256
10 10 320

Allow 1 square foot of space for each marijuana plant so that it can spread out and grow. The recommended wattage is what is required by the plants during their flowering stage. Flowering cannabis consumes significantly more power than the other growth stages, so it is used here as the base point. During the periods when your plants don’t need a lot of light intensity, it’s easy to switch off or dim the lights, but it’s not so easy to adjust when you need more.

If the recommended wattage seems low, remember that LEDs can be much brighter than other grow lights. To illustrate, a typical HID light draws 45 watts of power to provide lighting per square foot. In comparison, LEDs only need 32 watts to produce the same light intensity.

IV. Proper Placement of LED Grow Lights

As mentioned earlier, you can position LED lights closer to the plants because they produce less heat than HID lamps. Compared to fluorescent lights, you should place them farther away. Therefore, if space is an issue, LEDs might not be right for you.

Even after running for several hours, it is still safe to touch an LED light. Nevertheless, this does not mean that they cannot cause heat issues. High-quality LEDs come equipped with heat sinks, which allow for the dissipation of unwanted heat. Nonetheless, you should maintain a distance of 30 to 45 cm (12 to 18 inches) between the lights and the plant canopy.

A light burn can occur if the plants are too close to the LEDs. Should this happen, you would see leaves turning yellow or brown, with the edges curled up. If left unchecked, the leaves eventually become crispy and brittle. Light burn affects the plant’s normal photosynthetic process because the leaves can’t do their work. Hence, you should do your utmost best to keep the leaves healthy.

The easiest way to check if your lights are too close is to stick your hand under them. If it is too hot for you, then it is also too hot for the plants. Adjust the placement of the lights until the temperature feels comfortable.

You should also check if all parts of the plants are getting sufficient light. The primary lens of an LED directs light at a 160- or 180-degree angle. You might have to purchase a secondary 90- or 120-degree lens to refocus light. Each extra lens, however, reduces the output intensity by 8 to 10%. Furthermore, it would be best to cover all interior walls with aluminum foil (reflector panels) to bounce light to the plants.

V. Considerations for Each Growth Stage

Marijuana plants prefer bluish light for their vegetative stage and pink-orange light during the flowering phase. Fortunately, LED grow lights in the market work for both stages. They produce the full spectrum of wavelengths or colors that plants require. Unlike HIDs (MH + HPS), you only need one set of LED lighting from seed to harvest.

This type of fixed LED is undoubtedly convenient. Some growers, however, prefer to modify their setups to boost efficiency during each growth stage. For best results, purchase LED lights with a manual switch to change the color spectrum, from vegetative to flowering mode.

Let’s discuss the specific color and intensity needed for each growing phase to fine-tune your setup.

Seedling Stage

After the marijuana seeds sprout, they will need light to grow. The young plants, however, are still sensitive to intense light, so you must be cautious. Start with a gentle glow, then gradually increase the intensity.

To do this, position the lamps farther away from the seedlings at first. If there is a dimming option, then you should turn it down. Take care, however, to give the seedlings sufficient light. Otherwise, they will grow thin and lanky as they try to reach upward to catch more light.

At this time, your plants need the bluish end of the color spectrum, so activate the vegetative setting of your LEDs. Keep the lights on for 18 consecutive hours a day, with 6 hours of darkness.

Adjust the dimmer periodically to increase the intensity bit by bit. Avoid changing the intensity or the position of the lamps abruptly to prevent stressing your plants.

Vegetative Stage

With adequate light intensity, your plants will exhibit explosive growth during the vegging stage. They should get taller and bushier, with strong stems and healthy leaves. However, they could become spindly and gangling if there is not enough light. You can increase the light intensity by adjusting the LEDs to be closer to the plant’s upper canopy, and turning up the dimmer.

You can continue with the 18/6 light cycle for as long as you want the plants to remain in the vegetative phase. For some marijuana strains, you could even give them 20 to 24 hours of light a day to maximize growth. But eventually, you will want them to start their flowering phase – not unless you are keeping a mother plant for cuts.

Flowering Stage

Cannabis plants are photoperiodic, which means their development depends on the lengths of the daytime and nighttime periods. To induce flowering or budding, change the light cycle to 12 hours on, 12 hours off. The shorter daylight hours, in this case, simulates outdoor conditions in late summer or early autumn. Recognizing that, your plants would start the reproductive phase to ensure the survival of its species.

You can turn the LED dimmer to maximum intensity during this time. Switch the setting to flowering mode, which produces the pink-orange glow that is more suitable for this growth stage. Ensure that the lamps are not too near the plants, though, to avoid causing a light burn.

Remember: If it is too hot for your hand, then it is too hot for your plants. It is important to note that your plants must have uninterrupted darkness within the 12-hour nighttime period. Check your grow space to ensure that light does not leak in from outside. Otherwise, your plants will revert from budding back to the vegetative stage. Moreover, it could cause hermaphroditism. Hermaphrodite marijuana can still produce smokable buds. But they are not as potent or tasty as 100% female buds.

Use LED Grow Lights to Get Optimum Results

If you are thinking about which type of lighting to use for your marijuana grow room, give LED a try. Compared to traditional CFL and High-Intensity Discharge lights, modern LEDs are capable of producing the complete color spectrum for your plants. Furthermore, they emit less heat and are more cost-effective in the long run. They are also more flexible throughout your plants’ life cycle, and they come in a variety of configurations.

Learning how to choose and set up your LED grow lights is not at all complicated. After dipping your hands with this type of lamp, it does not take long to see the fantastic benefits. Come harvest time, expect to actualize your ultimate goal of colorful, sticky, and potent buds.