Choosing the best lights for growing cannabis and selecting the right system tailored to your specific needs is essential for successful growth.
This decision depends on several key factors, including light spectrum and intensity, energy efficiency, heat management, coverage area, durability, lifespan, and of course, your budget.
This guide will walk you through the most popular types of indoor grow lights and those important considerations to help you make an informed decision for your cannabis garden.
Types of Indoor Grow Lights
Fluorescent Lights
CFLs and other fluorescent lights, such as T5 and T8 bulbs, are often used by small-scale growers or for early plant stages like seedlings and clones. These lights emit low-intensity light and produce minimal heat, making them suitable for small spaces and early grow stages like the seedling stage and clone rooting.
ph: Ryan Lange – Unsplash
While inexpensive and easy to use, fluorescent lights are less efficient than HID or LED options for the flowering stage, as their lower light output can limit bud development. However, they are still popular for early-stage growth due to their gentler light.
Compact Fluorescent Lights (CFL)
CFLs are small, energy-efficient lights suitable for small grow spaces or as supplemental lighting. They are easy to set up and emit minimal heat, reducing the risk of burning plants. CFL lights are useful during the seedling stage, the vegetative stage and for rooting clones. They are not the best for the flowering stage but still work if that’s your only choice.
T5 Fluorescent Lights
T5 Fluorescent light are larger and more powerful than CFLs, offering better light coverage. They are ideal for seedlings, clones, and early vegetative growth stages. T5 lights are known for their efficiency and gentle light output.
ph: Ryan Lange – Unsplash
Advantages and limitations of fluorescent lights for cannabis cultivation
Advantages: Fluorescent lights are energy-efficient, affordable, and emit less heat, making them ideal for small grow spaces and early plant stages.
Limitations: They provide lower light intensity and penetration compared to HID and LED lights, making them less suitable for flowering stages or larger grow setups.
ph: Ryan Lange – Unsplash
High-Intensity Discharge (HID) Lights
High-Intensity Discharge (HID) lights like Metal Halide (MH) and High-Pressure Sodium (HPS) have been a staple in cannabis cultivation for years, offering intense light output for both the vegetative and flowering phases.
Metal Halide (MH) bulbs for vegetative growth
Metal Halide (MH) bulbs emit a blue-white spectrum, which is good for the vegetative growth stage of cannabis. This light spectrum promotes healthy leaf and stem development, resulting in bushier plants with strong, sturdy structures. MH bulbs effectively encourage vigorous vegetative growth, which is essential for a high-yielding flowering stage.
High-Pressure Sodium (HPS) bulbs for flowering stage
High-Pressure Sodium (HPS) bulbs produce a red-orange spectrum, perfect for the flowering stage of cannabis. HPS can be used throughout the plant’s life cycle, although sometimes it is only used during flowering due to electricity costs.
This spectrum stimulates bud production and enhances the overall yield and quality of the harvest. HPS grow light bulbs are renowned for their ability to promote dense, resinous flowers.
ph: Crystalweed – Unsplash
When cooling HPS bulbs in a cannabis grow, both Cool Tubes and Cool Boxes offer effective solutions.
ph: Alicia Muzio
Cool Tubes are cost-effective and provide excellent cooling by allowing direct airflow through a cylindrical glass tube, making them ideal for smaller setups. However, their light distribution tends to be more focused and less uniform.
Cool Boxes offer better overall light spread due to their larger reflective surface while still maintaining efficient heat removal through enclosed ducting, making them a better choice for medium-sized grow spaces.
ph: Crystalweed – Unsplash
Pros and cons of HID lighting systems
Pros: HID lights are highly effective for both vegetative and flowering stages, providing intense light that penetrates deep into the canopy. They are relatively affordable and widely used in the industry.
Cons: HID systems generate significant heat, sometimes requiring robust cooling solutions. HID bulbs have shorter lifespans compared to other lighting technologies. They consume a lot of electricity and during the seedling and vegetative stages, such intense lighting is not necessary, and can be replaced by energy saving options like CFL or LED. Spotting pests, diseases and deficiencies is more difficult with HID lights than with full spectrum ones. Make sure you scout your plants with natural or white light if you grow with HID.
ph: Alicia Muzio
Light-Emitting Diode (LED) Lights
LED grow lights are perfect for indoor cannabis growing during the whole plant life cycle due to their energy efficiency, lower heat output, and customizable light spectrums.
The “blurple” LED fixtures combine blue and red diodes, mimicking the natural light needed during different growth phases. They are a good and cheaper option but they use more electricity than the full spectrum LEDs and they lack the complete “full spectrum” benefits. One disadvantage is that you can’t spot pests, diseases and deficiencies as easily as with white light.
ph: Crystalweed – Unsplash
More advanced options include LED COB (Chip-on-Board) lights offering intense, white, focused light output and modern full-spectrum. They are good for all plant stages including flowering but they can raise significant heat. COB LED fixtures for example can raise a lot of heat but most of those lighting systems come with built-in cooling mechanisms. If this is not enough, consider implementing additional ventilation and cooling solutions.
Modern LEDs like the Samsung LM301B/H diodes provide a balanced light spectrum for all growth stages and are highly efficient, offering excellent yields with less power consumption. Full spectrum LED grow lights are the best option regarding efficiency but they have a higher initial cost. Most modern LED fixtures can dissipate heat without the need for cooling mechanisms.
ph: Alicia Muzio
These modern LEDs Full-spectrum LEDs mimic natural sunlight, providing a complete range of wavelengths beneficial for all growth stages.
Benefits of LED lights for indoor cannabis growing
LED lights are energy-efficient, produce less heat, and have longer lifespans compared to HID lights
LEDs offer precise control over light spectrum, allowing growers to customize the light for different growth stages.
LEDs can result in lower electricity bills and reduced cooling requirements.
ph: Crystalweed – Unsplash
When selecting LED lights, consider the light spectrum, wattage, and coverage area. Look for LEDs with high PPFD ratings and good heat dissipation features.
The upfront cost of LEDs is higher, but the long-term energy savings and reduced cooling needs can offset the initial investment.
Key considerations when choosing lighting for cannabis plants
Light Spectrum: Select lighting systems that provide a balanced spectrum of light for vegetative and flowering stages, respectively. Full-spectrum options closely mimic natural sunlight and can enhance overall plant health and productivity.
Light Intensity: Consider the recommended light intensity for cannabis plants at each growth stage. Ensure your chosen lighting system can deliver sufficient light levels to meet the plant’s requirements and promote optimal photosynthesis.
ph: Alicia Muzio
Energy Efficiency: Evaluate the energy efficiency of the lighting option to reduce electricity costs and minimize heat generation. LED lights are known for their energy-saving capabilities, making them a popular choice among cannabis growers.
Heat Management: Efficient heat dissipation is important to prevent heat stress and keep an ideal temperature range.
Coverage Area: Determine the size of your growing space and choose lighting that can adequately cover the entire area. Most fixtures come with proper information about the coverage area, make sure to check it out before buying.
Durability and Lifespan: Choose lighting systems that are durable, long-lasting, and require minimal maintenance. LED lights, for example, have a longer lifespan compared to traditional HID lighting options, but HID lamps are usually cheaper.
Budget: Consider your budget and weigh the upfront costs against long-term benefits. While high-quality lighting systems may have a higher initial investment, they can provide better efficiency and yield, leading to a higher return on investment over time.
Let’s explain these topics in a little more dept:
Light spectrum
By understanding the role of different light wavelengths in photosynthesis, and how it influences plant growth and development cannabis growers can fine-tune their lighting systems to promote healthy plant growth, optimize yield, and achieve desired characteristics during various stages of the plant’s life cycle.
Light spectrum and intensity are well explained in the other guide linked below. Make sure you read it to fully understand those key concepts.
Light intensity
Light intensity is the most important factor when it comes to growing healthy and productive cannabis plants. Cannabis plants rely on light as their primary source of energy. Providing the right light intensity can significantly impact the growth, development, and overall quality of your plants.
When it comes to light intensity, it is important to strike a balance. Too little light can lead to weak, spindly plants with poor bud development. On the other hand, excessive light intensity can cause stress, leaf burn, and stunted growth. Finding the sweet spot is essential for optimal plant growth.
ph: Alicia Muzio
Understanding the specific requirements of your strains and stage and adjusting light intensity accordingly can help you maximize yields and produce high-quality buds. Remember to strike a balance and monitor your plants’ response to ensure they receive the optimal amount of light for their growth stages.
ph: Premium cultivars – Unsplash
To learn about light intensity and spectrum your plants need for each stage, read the following guide:
Energy efficiency
When it comes to growing cannabis plants indoors, energy efficiency is a key consideration for both cost savings and environmental sustainability. Evaluating the energy efficiency of lighting options is essential to reduce electricity costs and minimize heat generation.
Traditional lighting systems, such as high-pressure sodium (HPS) lamps, have long been used in indoor cannabis cultivation. While they provide adequate light for plant growth, they are notorious for their high energy consumption and heat output. This not only leads to increased electricity bills but also necessitates additional cooling systems, adding to the overall energy expenditure.
To improve energy efficiency, many growers are turning to modern lighting options, such as light-emitting diodes (LEDs). LED lights have gained popularity due to their remarkable energy-saving capabilities. Compared to HPS lamps, LEDs consume significantly less electricity while providing the same or even better light intensity for plant growth. Additionally, LEDs produce less heat, reducing the need for elaborate cooling systems and helping maintain a more stable growing environment.
ph: Alicia Muzio
When evaluating lighting options for energy efficiency, consider factors such as the light output (measured in micromoles), the wattage consumed, and the light spectrum provided. Opting for energy-efficient LED lights with a balanced spectrum tailored to cannabis growth stages can significantly reduce electricity costs and minimize heat generation.
Heat management
Proper heat management is important when growing cannabis plants indoors or in greenhouses. Maintaining optimal temperature levels is essential for the plant’s health, growth, and overall productivity.
Indoor growers face the challenge of dissipating excess heat generated by lighting systems, especially high-intensity ones. If the temperature inside the growing space rises too high, it can lead to heat stress, nutrient deficiencies, and reduced yields.
To combat this, adequate ventilation and air circulation systems are crucial. Installing exhaust fans, intake fans, and oscillating fans can help remove hot air, bring in fresh air, and maintain a consistent temperature throughout the growing area. Monitoring the temperature closely using thermometers or environmental control systems is essential for both indoor and greenhouse cultivation.
Coverage area
Determining the size of your growing space and choosing appropriate lighting are crucial steps when cultivating cannabis plants indoors. For optimal growth and maximum yields, it’s important to provide space between plants to avoid overcrowding, which can hinder light penetration and air circulation.
Manufacturers usually specify the recommended coverage area for their lights, taking into account the light intensity requirements. Once you have determined the desired light intensity, you can select lighting fixtures that can cover the entire growing area.
To ensure uniform light distribution in big grow areas, it is advisable to use multiple light fixtures rather than relying on a single source. This helps eliminate shadows and ensures consistent coverage across the entire space.
Durability and lifespan
When it comes to durability and lifespan, there is a notable difference between high-intensity discharge (HID) and light-emitting diode (LED) light options for indoor cannabis cultivation.
While they are known for their high light output, HID lights have a relatively shorter lifespan. On average, HPS lamps last around 10,000 to 20,000 hours, while MH lamps have a slightly shorter lifespan. Frequent replacement of bulbs is necessary to maintain optimal light intensity, which can be both time-consuming and costly.
On the other hand, LED lights offer exceptional durability and lifespan. LED technology has made significant advancements in recent years, allowing for longer-lasting and more reliable fixtures. High-quality LED lights can last up to 50,000 to 100,000 hours or even more, depending on the manufacturer and specific model. This extended lifespan not only reduces maintenance and replacement costs but also provides consistent and reliable light output throughout the lifespan of the fixture.
Additionally, LED lights are less prone to sudden failures or burnouts compared to HID lamps. LED technology does not rely on filaments or electrodes that can degrade over time. Instead, LEDs operate using solid-state components, making them more resistant to shocks, vibrations, and temperature fluctuations.
Considering the longer lifespan and enhanced durability of LED lights, they are a preferred choice for many indoor cannabis growers
Budget
When budgeting for lighting options for cannabis plants indoors, there are several factors to consider, including initial costs, operational expenses, and long-term savings.
HID lights, such as high-pressure sodium (HPS) and metal halide (MH) lamps, have lower upfront costs compared to LED lights. These traditional lighting options are readily available and have been used for years in indoor cultivation.
However, it’s important to factor in ongoing expenses such as energy consumption and bulb replacements. HID lights have higher energy demands and shorter lifespans, leading to increased electricity bills and more frequent bulb purchases.
LEDs are highly energy-efficient, consuming less electricity while delivering the same or even better light intensity. Additionally, LEDs have longer lifespans, reducing the need for frequent bulb replacements and associated costs.
When budgeting, consider the size of your growing space, the number of plants, and the desired light intensity. Calculate the total wattage required and compare the costs of HID and LED fixtures accordingly.
It’s important to view the investment in lighting as a long-term strategy. Although LED lights may require a larger initial budget, they offer cost savings in energy consumption and maintenance, making them a financially sound choice for indoor cannabis cultivation.
ph: Teanna Morgan – Unsplash
Conclusions
Selecting the right lighting for cannabis plants indoors is a critical decision that directly impacts their growth, productivity, and overall success.
By evaluating factors such as light intensity, energy efficiency, heat management, and budget considerations, growers can make informed choices to optimize their cultivation operation.
Exploring and experimenting with different lighting setups can lead to optimal results in cannabis cultivation. Each grow environment is unique, and what works best can vary. Trying different light intensities, spectrums, and configurations can reveal the ideal setup for your specific conditions. Stay informed about new technologies and techniques, and don’t hesitate to adjust your approach based on observations and results. This willingness to experiment and adapt is key to mastering indoor cannabis cultivation and achieving the best possible yields.
