HPS or LED? Or why not both? Hybrid lighting systems for cannabis cultivation

In cannabis growing, choosing the right lighting system is key to maximising both the quality and quantity of your harvest. Nowadays, there are two main systems that dominate the market: High-pressure sodium (HPS) and light-emitting diode (LED) lamps. Instead of choosing between one or the other, many growers are now opting for a middle-ground solution that combines the best of both technologies. By setting up a hybrid system, they can make the most of both whilst mitigating their limitations.

When it comes to growing marijuana plants in controlled environments, lighting is everything. Just as the sun is crucial for plant growth outdoors, the right kind of artificial lighting can make or break your efforts indoors. And, while there’s a wide range of lighting options available, two of the most popular are high-pressure sodium (HPS) and light-emitting diode (LED) lamps.

Each of these lighting systems has its own strengths and weaknesses; but what if you could get the best of both worlds? That’s where the idea of mixing HPS with LED lamps comes in – a strategy that can provide your plants with the perfect balance of light spectrum, energy efficiency, and temperature control.

Why choose hybrid lighting?

HPS lights can meet the needs of grows and short-term budgets, but growers who take a longer-term approach usually choose LED lights –these are more energy and cost efficient, and provide optimal light with better spectral control.

But if LEDs are superior in most aspects and applications, why would growers consider a hybrid lighting setup that includes HPS lamps? Many are interested in switching to LED technology but cannot commit to the higher initial capital investment that LEDs entail, despite the long-term energy and cost savings. Therefore, depending on the budget, facilities, and growing conditions, it can sometimes be beneficial to implement a hybrid lighting strategy. Let’s see why.

The radiant heat of HPS

To grow and develop properly, plants need the right temperature for each stage of their life cycle. The significant amount of heat radiated by HPS systems compared with the relatively cold running of LEDs can help achieve this in a hybrid lighting environment, helping to balance the thermal load for a grow and giving plants the temperature they need, whilst also helping to offset heating costs in the colder months. On the contrary, in the spring and summer months, when light levels need to be increased without raising indoor temperatures, LEDs can be used to keep temperatures low.

Improved spectral control

When it comes to providing the light quality that your plants need, HPS lamps simply cannot offer a highly customised spectrum. In fact, when PAR (photosynthetically active radiation) is observed (i.e., the blue, green, and red spectrum), only 6% of the light emitted by HPS lamps is blue light. And by providing very little blue light, HPS lamps are depriving plants of a critical wavelength that governs growth.

Let’s say, for instance, that you want to promote more compact growth using blue light – adding customisable LEDs will allow you to achieve this. And if you want to induce bud development by introducing more red light, this can be achieved with a hybrid lighting solution that includes LED and HPS lamps – this provides an effective and energy-efficient way to obtain the desired results.

Better distribution of the light source

Another point to consider is how each light source distributes the light. LEDs emit light in a single direction, and the intensity decreases as you get further from the source. Because of this directional distribution of light, shadows can be enhanced if lights are placed too close to the canopy.

On the other hand, HPS lighting provides a more diffuse lighting pattern because it uses reflectors to direct the light. Plants can use diffuse lighting more efficiently than directional lighting because of the way this light penetrates the foliage. Diffuse lighting also tends to lead to greater growth than that produced by direct light from above. Therefore, HPS lighting should be installed for the light to overlap and penetrate horizontally, so that the shadows are reduced. A combination of HPS and LED lighting provides the perfect distribution of diffuse and directional light.

Intercanopy lighting

The implementation of hybrid lighting systems with intercanopy technology (Intercanopy Lighting or ICL) is also becoming increasingly appealing to growers, as this can help improve both the quality and quantity of the buds. This method involves using HPS lamps for overhead lighting, whilst also placing LED lights strategically between the layers of the plant to help increase light penetration and ensure that the lower parts of the canopy also receive proper lighting.

Unlike traditional setups that only illuminate from above, intercanopy lighting leads to a more even development of all areas of the plant, including the lowest branches. Studies suggest that not only does this technique stimulate biomass production but also promotes the synthesis of cannabinoids and terpenes by optimising the lighting environment at each stage of growth.

Greater energy efficiency

Lastly, energy efficiency can also be improved with a combination of HPS and LED lights. While HPS lamps are powerful, they also use a lot of energy. However, by integrating LED lights in your grow, you can reduce the overall energy consumption without sacrificing on light intensity. This balance lets you enjoy the benefits of both systems whilst also potentially decreasing your electricity bill.

Unity gives strength

As you can see, the choice between HPS and LED lighting no longer needs to be an exclusive decision. Hybrid systems represent a smart choice for cannabis growers who want to maximise the yield and quality of their crops. By combining the power and penetration capacity of HPS lamps with the efficiency and versatility of LED lights, it is now possible to create an ideal growing environment that supports every stage of plant development, from germination to flowering. For those looking for the best of both worlds, hybrid lighting is certainly an option to consider in the competitive and growing cannabis market.