Installing between traditional lighting systems like High Pressure Sodium (HPS) or Metal Halide (MH) and newer LED technology can be a complex choice. Factors like energy consumption, return on investment (ROI), maintenance costs, and their impact on plant growth must be taken into account. Many growers are interested in updating to LED lighting due to benefits such as energy savings and the ability to adjust light spectra. However, since the LED industry is still relatively young and initial costs can be high, it may seem impractical to switch entirely. Implementing a hybrid lighting system is an efficient way to take full advantage of the distinct benefits that LED and HID lights offer.
What Is a Hybrid Lighting System?
A hybrid lighting system refers to the installation of both LED and HPS lighting (or even a combination of different light styles such as HPS and MH) in a single grow setting.
When using an LED and HPS hybrid setup, this combination offers an optimal balance between diffuse light distribution and spectral efficiency. It provides the flexibility to benefit from the radiant heating properties of HPS lighting while also extending the supplemental lighting period into the spring using LED lights when outside temperatures and daylight hours increase. Implementing a hybrid lighting system helps reduce initial capital expenditure and allows growers to manage costs by utilizing their existing infrastructure.
Lighting Overview
HPS Lights
High pressure sodium (HPS) lighting has long been favored in commercial horticulture due to its effectiveness. The spectrum of HPS lights is rich in red wavelengths, which helps long-day plants like cannabis grow and flower. However, HPS lights lack sufficient blue wavelengths, which can inhibit stem elongation. Additionally, HPS lights emit abundant radiant heat in the illuminated area. This heat not only is beneficial for heat-loving crops such as tomatoes, peppers, or cannabis but also helps offset heating costs with natural gas or electricity.
MH Lights
Metal halide (MH) and ceramic metal halide (CMH) lights have traditionally been used during the vegetative stage of plant growth. These lights offer a broader spectrum and emit high levels of blue light. The blue light restricts blooming response and raises chlorophyll levels, thereby speeding up the plant’s photosynthesis. Moreover, the blue and ultraviolet (UV) wavelengths have been found to stimulate the plant’s defense mechanism, leading to increased metabolic activity responsible for the synthesis of terpenes and cannabinoids.
LED Lights
In terms of spectral efficiencies, HPS lamps produce a significant amount of light that is not beneficial for plants, resulting in lower efficiency compared with LEDs. LEDs, on the other hand, allow for targeted emission of wavelengths that are specifically useful for plant growth, making them more efficient spectrally. LEDs also offer advantages such as higher energy efficiency and longer lifespan.
Another benefit of LEDs is their impact on the temperature in the grow room. Unlike HPS lights, which emit radiant heat in the direction of illumination, LEDs dissipate heat away from the area being illuminated through convective heat. This means you can put the light close to the crop canopy without the risk of burning. However, this lack of heat means that during colder months, heating costs may be higher with LEDs, particularly in northern climates. Studies have indicated that in such cases when additional heat is required, the overall energy costs between LEDs and HPS lights are the same.
What Are the Benefits of Having an LED and HPS Hybrid Lighting System?
Having an HPS and LED hybrid lighting system offers several benefits, such as enhanced spectral control, better temperature, and improved distribution of light.
Enhanced Spectral Control
Hybrid lighting systems offer the advantage of optimizing the quality of light for plant growth. Different crops have specific light spectrum requirements at each stage of their growth. HPS lighting alone cannot provide a highly customized spectrum of light. In terms of PAR, which includes the red, blue, and green wavelengths, only 6% of the light produced by HPS lights is blue light. This lack of blue light deprives plants of a crucial wavelength necessary for their growth.
By incorporating customizable LEDs into the lighting system, you can tailor the spectrum of light to meet specific needs. For instance, if you want to promote more compact growth, adding blue light through LEDs can help achieve that. Similarly, if you want to induce fruiting, you can adopt a hybrid lighting solution with customizable LEDs that can produce red and far-red light. Particularly during seasons with low sunlight, supplementing HPS lighting with LEDs offers an effective and energy-efficient approach to obtaining desired crop results while maintaining control over light quality.
Provide the Optimal Temperature
Maintaining the right temperature plays a key role in the healthy growth of plants at every stage. In a hybrid lighting setup, the heat emitted by HPS lamps and the relatively cool operation of LEDs can help achieve optimal temperature conditions throughout the seasons. During colder months, the heat generated by HPS lighting can offset the need for HVAC (heating, ventilation, and air conditioning) usage. By implementing a hybrid lighting strategy that combines HPS and LED, you can fully capitalize on the advantages of supplemental LED lighting and HPS lighting.
Conversely, in warmer months when additional light is still required for crops but not the extra heat, cooler LEDs can be utilized. This allows for providing the necessary daily light integral (DLI) and photoperiod without overheating the grow space.
Improved Distribution of Light
LEDs emit light in a specific direction, and the intensity of light diminishes as your plants are placed away from the light source. This can lead to increased shadows if LEDs are placed too close to the plants. In contrast, HID lighting, such as HPS lamps, provides a more diffuse lighting pattern by using reflectors to direct the light. Plants can utilize diffuse lighting more efficiently as it allows light to penetrate into the canopy effectively. Diffuse light typically results in better plant growth than light from above.
To maximize the benefits of HPS lighting, installation of HPS lighting should be done such that the light overlaps to lessen shadows and penetrates in a horizontal direction. By using both HPS and LED lighting, you can achieve an optimal distribution of both diffuse and directional light. This hybrid approach allows plants to receive the necessary wavelengths when they need them, while also benefiting from the radiant heat and diffuse light provided by HPS lights. Additionally, incorporating LEDs into the system enables the extension of light usage into the spring months without adding excessive heat load. This combination of tried-and-tested HPS lights with efficient LEDs provides a comprehensive lighting solution for plants, addressing their specific light and heat requirements.
What Are the Benefits of Having a MH And HPS Hybrid Lighting System?
Another type of hybrid lighting system worth mentioning is HPS and MH lighting. This approach means adding different light spectra within the same grow setting. Specifically, it entails using a higher red HPS light in combination with a higher blue MH or CMH (Ceramic Metal Halide) light. By implementing a well-designed hybrid light system that incorporates both MH and HPS lighting, growers can enhance crop productivity and improve the quality of their harvest.
In flowering rooms, where growers may wish to experiment with increasing terpenes or cannabinoids by introducing more blue light, MH lamps can be a more cost-effective option compared with buying LEDs, which can be 3-5 times the price. Additionally, some growers prefer mixed spectra for vegetative growth, where plants receive a balanced spectrum suitable for growth without enough red light to initiate a flowering response.
Develop Your Ideal Hybrid Lighting System With MokoLight
Switching to a full LED system to reduce heat and energy waste may not be financially viable for all cultivators. However, implementing a hybrid lighting strategy can serve as a valuable intermediate step toward a long-term business model or retrofit. It allows growers to take full advantage of both LED and traditional lighting systems.
If you are interested in implementing a hybrid lighting system but are unsure of how to proceed, we recommend MokoLight. As a market-leading LED light design manufacturer with 16+ years of experience, MokoLight is able to provide the best support to help you successfully adopt a hybrid lighting solution. We provide 24/7 online service, please feel free to reach out to us.