Under-Canopy Lighting: Boost Yields, Bud Quality & Color

In the continuous quest for higher yields, every aspect of the plant’s environment needs to be optimized. Under-canopy lighting, also known as sub-canopy lighting, offers a compelling solution to common lighting challenges faced by indoor growers.

This targeted approach to lighting is designed to boost lower plant growth, which is crucial for maximizing overall yield and quality.

What is Under-Canopy Lighting?

Under-canopy lighting refers to the practice of positioning additional light sources around the lower parts of the indoor grown plants. 

This technique is essential for ensuring that light reaches the lower leaves and branches, which often remain under-lit in traditional top-lighting setups. By targeting these areas, growers can stimulate photosynthesis across a larger portion of the plant. This helps to promote a healthier and more uniform development.

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The Science Behind Under-Canopy Lighting

Under-canopy lighting transforms indoor horticulture by actively delivering light to the lower parts of plants, which are usually shaded and underexposed. This method ensures better light penetration to areas that traditional overhead lighting cannot reach, promoting healthier growth and more uniform development throughout the plant, ultimately boosting both yield and quality.

This innovative lighting strategy employs scientifically designed lights placed beneath the plant canopy. These lights target areas that traditional overhead lighting systems cannot reach effectively.

The science behind sub-canopy lighting centers on the principle of photosynthetically active radiation (PAR). PAR is crucial for plant health as it involves the wavelengths of light that plants use for photosynthesis. 

Typically, the upper leaves and branches of a plant absorb significant amounts of this light. This leaves the lower parts of the plant with insufficient exposure. Sub-canopy lighting compensates for this imbalance by delivering targeted PAR to these underlit areas. This promotes much healthier growth and more uniform development across the entire plant.

This approach not only optimizes the photosynthetic efficiency but also significantly improves the plant’s overall energy utilization. Enhanced light penetration encourages robust growth in lower branches, leading to increased biomass and potentially higher yields.

Additionally, this method can improve the quality of the produce, as better light exposure stimulates the production of essential oils, flavonoids, and terpenes. These are vital for flavor and aroma in many plants.

Adopting under-canopy lighting is also a step towards energy efficiency. By improving light usage, growers can achieve better results with less energy, aligning with sustainable farming practices. This lighting strategy represents a blend of botanical science and innovative technology, paving the way for future advancements in precision agriculture.

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Key Benefits of Under-Canopy Lighting

Yield Increases From 25% – 35%

The most exciting results of adding under-canopy lighting to your grow room are consistent and reliable yield increases. Whether you are a new grower, craft grower, or professional working in a large facility, we are repeatedly seeing huge yield increases. We are confident you will achieve these results as well. The massive increases in average yield can give growers up to a 1-run ROI (Return On Investment).

Improved Lower Bud Structure & Shape

Sub-canopy lighting can significantly improve health and yields by enabling lower buds to develop more fully and contribute significantly to the total harvest. The even level of plant and bud maturity is a huge positive, as you will have more usable and high-quality A/B tier buds. 

Consistent Color Throughout The Full Plant

Plants grown with supplemental under-canopy grow lights show consistent color from the top of the plant to the very bottom. This is a huge benefit as typically lower branch flowers lack bold beautiful colors (think purple) as the top flowers. 

Less Undergrowth Clearing/Trimming

One of the most significant benefits you will notice is that you will no longer spend excess time trimming undeveloped undergrowth. All flowers on the plant will have the same potential for solid formations, aiding to better yields, but also saving manual time trimming

Save Time Sorting Flower Post-Harvest

With even bud development across the entire plant, the flowers will be more visually appealing and uniform, eliminating the need for sorting by grade. When using under-canopy lighting, all flowers are top-tier.

Increased Light Exposure

Under-canopy lighting ensures that all parts of the plant receive adequate light, which is vital for consistent growth and prized compound & terpene production.

Enhanced Photosynthesis

By increasing light exposure to the lower leaves, sub-canopy lighting boosts the overall rate of photosynthesis, supporting more vigorous growth and flowering.

Energy Efficiency

Implementing LED-based sub-canopy lighting systems offers the benefit of energy efficiency, which is crucial for sustainable cultivation practices.

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Proper Implementation Under-Canopy Lighting

• Choose the Right Lights: LEDs are recommended for their broad spectrum and low heat output. This makes them ideal for use near plant foliage without risking heat stress.
• Optimal Placement: Lights should be strategically positioned to ensure even coverage. Placing lights too low will cause the light to hit the substrate instead of the plant. Adjustable fixtures can provide flexibility as plants grow and canopy density changes.
• Monitoring and Adjustment: Regular monitoring and adjustment of light placement and intensity are necessary to adapt to the growth stages and ensure optimal light distribution throughout the growing cycle.
• Slowly Introduce Light To Full Intensity: One of the most important factors of proper implementation of under-canopy lighting is to minimize stress on the plant. You can do this by slowly ramping up the light intensity to 100%. We recommend turning on your light at about 45%-50% on day 1 of flower, then slowly increase it over the next 18-21 days. 

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Under Canopy Lighting & VPD Interaction

The connection between sub canopy lighting and Vapor Pressure Deficit (VPD) is significant in indoor cultivation. Both elements play crucial roles in creating an optimal growing environment.

Vapor Pressure Deficit (VPD) is the measure of the difference between the moisture currently in the air and the maximum amount of moisture the air can hold when fully saturated.

Essentially, VPD indicates the potential for evaporation and transpiration in plants. It’s an essential factor because it influences how well plants can uptake water and nutrients through their roots and release water vapor through their stomata. Managing VPD helps optimize plant growth by promoting efficient water and nutrient uptake and preventing issues like wilting or stress.

Sub canopy lighting impacts VPD primarily through its effects on temperature and humidity within the plant canopy. Here’s how under-canopy lighting interacts with VPD:

Temperature Regulation

Under canopy lighting can directly affect the temperature around the lower parts of the plants. Since VPD is sensitive to temperature changes, adding light sources can increase the local temperature, thereby affecting the VPD. The additional heat ends up being a net positive as it evens out the VPD stratification between the top half of the plant and the lower half of the plant.

Humidity Control

By illuminating the lower parts of the plants, under-canopy lighting can also influence the microclimate’s humidity levels. This localized lighting can cause localized transpiration, where plants release moisture into the air. Managing planting density helps eliminate any microclimates and potential issues in the lower half of the plant.

Enhanced Growth and Transpiration

Properly implemented sub canopy lighting promotes healthier growth and increases leaf density. These two factors will increase the overall transpiration from the plants. More transpiration can alter the humidity levels around the plants, thereby influencing the VPD. Growers need to adjust their environmental controls to maintain an optimal VPD, ensuring that plants can transpire and photosynthesize efficiently without undue stress.

Balancing Act

The key for growers using under-canopy lighting is to balance the light benefits with controlled adjustments in their environment. By monitoring and adjusting temperature and humidity levels in response to changes brought by sub-canopy lighting, growers can maintain an ideal VPD.

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Under-Canopy vs. Inter-Canopy Lighting

You’re not alone if under-canopy lighting is on your radar for your greenhouse or grow room. Recently, there has been significant interest among growers in using lighting in various placements and angles to cater to their plants’ requirements.

This approach includes overhead top lighting, inner-canopy (inter-canopy/intra-canopy) lighting within the plant canopy, and under-canopy lighting positioned below the plants.

Although these sound similar and are both used to help increase light in the middle and bottom half of the plant which usually lacks lighting from traditional overhead lighting, they are technically different.

As this new technology becomes more popular with growers, the terms for the two will most likely become misused and confused.

Both methods aim to enhance plant productivity but differ in light placement and distribution strategies. Below we give a full breakdown and comparison of the two types with definitions.

Definitions of Intercanopy Lighting (ICL) & Under Canopy Lighting (UCL)

Intercanopy Lighting (ICL) – A lighting source designed to be in between 2 canopies, illuminating sideways in either direction. Lights are usually suspended from above between two rows of plants. Inter canopy was initially designed for vine crops such as tomatoes and peppers, which have a longer fruiting period than specialty indoor-grown plants.

Intracanopy Lighting – Similar to Intercanopy Lighting but defined as being within one singular canopy instead of in between 2 canopies.

Under Canopy Lighting (UCL) – A light source designed to be placed underneath the canopy, illuminating upwards. Lights are usually supported from below and placed between the substrates of two rows of plants.

Truth About Intercanopy Lighting (ICL)

1. Placement – Suspending ICL at the right height is difficult

• ICLs must be placed at the correct height to maximize inner canopy lighting. This can be difficult for some plants, which have varying sizes depending on the cultivar.
• Due to the need to support some plants with trellis, ICLs must be suspended in place before plants reach their maximum height. Once the trellis has been placed, it is very challenging to install ICLs without damaging sensitive tissue and increasing labor costs.
• Laborers are often tasked with guessing the height of the plant post stretch and, thus, guessing where to place ICLs. This leads to inconsistent results and workflow pinch points.

2. Effects on Labor – Inter canopy is an obstacle that labor must work around.

• With ICLs inside the canopy, plant maintenance such as de-leafing and under-clearing becomes more complicated and labor intensive. ICLs impede the ability to manage hard-to-reach areas within the canopy.
• IPM sprays cannot penetrate as deep into the canopy with ICLs hanging in the way. Often, this causes areas in the canopy that sprays cannot reach, leaving refuge for pests and pathogens.
• Harvesting with ICLs adds another layer of difficulty to an already challenging process. First, the outside row of plants must be harvested, and then workers stop to remove the ICLs. This process repeats twice on every bench, extending time on an already long day.

3. Changes in Pruning – Higher plant maintenance/labor costs

• When a light source is inside the canopy, leaves grow towards it. This causes leaves to surround the ICL and suffocate it. To reach the full potential of ICLs, labor must de-leaf heavier to unblock the lights. This leads to higher labor costs and a higher likelihood of damaging sensitive plant material.

4. Yield potential lower vs. UCL

• While inter-canopy lighting seems like an excellent remedy for increasing yields, the overall yield gain compared to under canopy lighting is much lower. ICLs only focus on the middle of the plant, whereas under canopy lighting focuses on lighting the plant in its entirety.
• ICLs are also less intense due to their positioning inside the canopy. Their intensity more closely resembles a clone light than a flowering light. Intensity and yield are closely related.

Facts About Under Canopy Lighting (UCL)

1. Placement – Supporting UCL from below is ideal

• Under-canopy lights are supported by stands that can be adjusted to match the height of the plant’s genetics. You can easily modify the height at any point in the flowering phase to ensure the plants receive sufficient light based on their growth.
• Adjustable stands allow facilities to create repeatable SOPs based on genetic growth habits or facility design. For example – multi-tier grows may only set their stands to 8”, while single-tier grows may prefer placing UCLs higher off the bench.
• The lowest setting recommended for UCLs is for the base of the light to be flush with the top of the substrate. This activates as much canopy depth as possible without adding unnecessary heat to the substrate.

2. Effects on Labor – UCL does not disrupt workflow

• UCLs sit below the canopy without disrupting workflow or plant maintenance. While workers may need to adjust their reach from a different angle, they can still perform all maintenance tasks with minimal interference.
• UCLs do not affect IPM regimens. After sprays, the lights can be wiped down to remove any residue from the lens.
• UCLs can be removed from the room the day before harvest. This allows your harvest to go as planned without interruption. Lights can also be kept in the room during harvest and removed after plants have been removed.

3. Changes in Pruning – Lower plant maintenance/labor costs

• Under canopy lighting activates the bottom 1⁄3-1⁄2 of the plant. This means there is less of a need to under-clear or “skirt” the under-canopy. Instead, focus on strategic de-leafing to open plants and allow upward penetration of UCL. UCLs dramatically reduce the time needed for plant maintenance on each run.
• We recommend two touches during the flowering process: an initial thinning of big fan leaves that may impede the upward mobility of the light. It’s best to do this after plants have stopped stretching and will start bulking soon. Secondly, a heavy strip to help uniformity of color, maturity, and bud structure from top to bottom of the plant. It’s best to do this early in the ripening phase.

4. Yield potential much better for UCL

• The overall goal of UCls is to light plants uniformly from top to bottom. Expect yield increases to start around 20% and grow to over 35%+ as you become more familiar with the fixtures.
• You can control 120w dimmable fixtures to achieve DLI (Daily Light Integral) targets and match the light intensity (measured in µmol) across the top, middle, and bottom of the canopy, ensuring consistent and optimized light exposure throughout the plant’s growth.

Hydrobuilders Take On Under Canopy Lighting vs. Inter Canopy Lighting

For growers looking to optimize yield and reduce labor costs, under-canopy lighting (UCL) is the clear superior choice. It offers significant yield improvements, is easier to integrate into existing operations, and provides a more uniform development of the entire plant without the complexities associated with ICL systems.

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Enhance Your Grow With Faven Lighting

The two custom spectrums, R6 and R8, work effectively in rooms that use both traditional HPS lighting and modern LED grow lights.

R6 lights (60% red) complement HID (HPS) Top Lights that are high in ROY

R8 lights (80% red) complement Full Spectrum LED Top Lights.

This allows cultivators to exercise greater control over the quality of the product they produce. While adding Favens to your facility will increase yield, increasing the product quality is also a top priority.

Our customers are routinely seeing a 25%-35% increase in yields when implementing Faven Lights in their grow rooms.

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Final Thoughts On Under-Canopy Lighting

The adoption of under-canopy lighting is becoming a game-changer in the cultivation world. The addition of lower canopy lighting in an indoor grow setup compensates for the lack of natural sunlight. This significantly boosts the lower plant development, leading to increased yields and higher-quality harvests. 

By strategically implementing and managing under-canopy lighting, growers can unlock the full potential of every indoor-grown plant. In a world of ever-changing technology enhancements, what might seem like a small factor can make the biggest difference. 

Be ahead of the curve, and take advantage of the next big leap in controlled environment agriculture with under canopy lighting. 

Need help determining the layout or have questions before placing your order? Our experienced cultivation staff is always available to answer any questions you might have regarding Faven Lighting. Give us a call at 888-815-9763 today!