Hybrid = LED + HPS Grow Light Case Study

  • 10% to 25% increase in yield

  • 50% reduction in power consumption

  • 50% reduction in heat

LED Grow Lights

LED grow lights are relatively new, yet they are making great strides in horticultural circles. Low power consumption, precision light placement, very low maintenance cost, long operational life, and low thermal emissions are huge upsides for greenhouse and indoor growers. Unfortunately, there are many choices in LED grow lights and not all of them actually attain their claims, so unless you know what to look for, you could be throwing away a lot of money.

Like any new technology, there are many manufacturers out there looking to cash in on the buying surge, and like anything else of a technical nature, not all are qualified, or experienced.

Of great concern to the purists in the field are manufacturers that do not specialize in grow lights, or even LEDs. In the marketplace, you will see many LED grow lights that appear almost identical, with the exceptions of aesthetic differences, like paint and power cord color, and different switches. These units come from a handful of vendors offshore, which sell to anyone with cash-in-hand. Unfortunately, most of these companies miss the boat when it comes to producing a highly effective LED grow light, mainly because grow lights are not their primary interest. Some of these companies will allow their clients to specify which LEDs go into their LED grow lights. While this is definitely a great option, simply changing frequencies of LEDs might make a good LED grow light, but it doesn’t necessarily make a GREAT LED grow light.

There are many factors involved in producing a true industrial-grade LED grow light. Thermal management should be of great concern when using LEDs. Airflow paths and volume of air moved are critical to the longevity of LEDs and power supplies, as are the types of materials used and their precise placement in the system. Poor design in these areas is not always evident to the buyer, but will manifest themselves down the road in terms of shortened LED and power supply life. If your LED grow light dies at 20,000 hours instead of the advertised 50,000, you most likely would have no claim against the company – the warranty would most assuredly be expired and the company may not even be in business.

However, there are also a few companies out there which concentrate on getting things right, and that take LED grow lights seriously. These companies focus all of their efforts on perfecting the technology and furthering the fight to bring credibility to the LED grow light industry. While some of their product offerings may appear similar to the others, when one takes a closer look, they will see that there are indeed significant differences.

Credible companies deploy high quality LEDs and power supplies, high-end MCPCB’s (Metal Clad Printed Circuit Boards), superior thermal management materials and techniques, and true industrial-quality design to their products. These companies also show faith in their product’s design and manufacturer, offering no-gimmicks warranties of three years, or more. Although the industry is in its embryonic stages, we are starting to see convincing video and written testimonials, as well as positive word-of-mouth advertising for a few products.

Pros of LED Grow Lights

  • Long life expectancy

  • Almost no excess heat

  • Very precise footprints (light output patterns)

  • Low operating costs

  • Endless spectrum possibilities

  • No UV (unless equipped)

  • No infrared (unless equipped)

  • High yield per Watt

Cons of LED Grow Lights

  • High initial cost

  • Low penetration (requires different growing techniques)

HID Grow Lights – Comparison to LED

High Intensity Discharge (HID) grow lights have been around for a long time. High Pressure Sodium (HPS) lamps are the product of choice when it comes to product yield, and HPS grow lamp manufacturers are constantly making changes to their lamps’ spectral (color) properties to increase this yield even further.Unfortunately, true full spectrum lighting is not an offering in the HPS lighting world. Metal Halide and Fluorescent lighting are also used as grow lights, but usually only in the beginning and vegetative stages of growth. Since HPS technology is the choice for almost all flowering, we will focus on this lighting.

Pros of HPS (or of HID?) Grow Lights

  • Initial setup is less expensive

  • Parts are relatively inexpensive

  • They have the lighting power to “brute force” plants into growing and harvesting

  • They provide penetration through the plant canopy

Cons of HPS Grow Lights

  • High operating cost

  • Excessive heat output that frequently necessitates costly refrigeration and ventilation

  • Frequent lamp replacement

  • Fast light depreciation (dimming) in the first 100 hours of use

  • Excessive power consumption (much wasted producing heat)

  • Ballasts draw significant power and are costly to replace

  • Low yield per Watt

Hybrid Systems = HPS + LED

Hybrid systems, or using a combination of different types of lighting to achieve higher product yield is becoming more commonplace. Using two different technologies can allow us to combine the best of each of the technologies and hopefully, eliminate or minimize the worst parts. In the case of hybrid lighting, by using HPS and LED grow lights simultaneously, we can accomplish quite a bit.

By using a lower wattage HPS light (<1000W) and fewer LED grow lights (strategically placed around the grow area) we maximize the benefits of both technologies:

  • Lower initial cost to purchase than only LED grow lights

  • Much lower operating cost than HPS alone

  • Eliminates excess heat produced by only HPS

  • The smaller HPS light provides just enough heat for the plants

  • Extended lighting area coverage (including the fringe of the grow area)

  • Better spectrum availability

  • Lower replacement costs

  • Great penetration

Many Super Grow LED customers are deploying hybrid lighting setups. This is made possible by our minimized, but industrial strength, construction, which allows lights to be strategically placed in and around any grow area. In the case of hybrid setups, a lower-than normal Wattage HPS is placed in the center of the grow area (i.e. 400 W replaces a 1,000 W) and in most cases, four to six LED grow lights area placed around the edges of the HPS lighting hood. The case study below will explain more about an actual setup one of our customers is using to great success.

Case Study

This is a combination study of two individual growers. Not everyone will achieve the same results. Both are avid growers and students of botany and biology. They are very particular about their plants and everything that influences them, including size/width, environment, water quality and nutrients.

The hybrid (HPS/LED) grows studied were compared to identical grows that did not use LED lighting.

The most popular HPS lamp (bulb) of choice was the 400W SunMaster Dual Spectrum. This unit is known to produce denser plants and fruiting. In one setup, four LED grow lights (100W total) were mounted outside the HPS hood fixture, two on each side, but closer to the plants than the HPS. In the other, six (150W total) were mounted in a similar fashion, three on either side of the HPS fixture.

The growing method known as Sea-of-Green (SOG) or Screen-of-Green (SCROG) was established in all of the test areas, hybrid and otherwise. This is recommended for any LED lighting in order to compensate for the reduced penetration power. For those not familiar with these growing methods, the key is to bring all of the flowering sites in direct view of the lighting, by trimming the canopy undergrowth. Flowering sites are multiplied by pruning top branches, allowing them to split several times. An average of 16 flowering sites per plant was maintained.

The hybrid grows showed significantly improved yield and the end dry weight of the product showed a 10%-25% increase over the HPS-only grows. There was a dramatic increase in flowering over the entire canopy, not just in the “sweet spot” under the HPS. Flower density improved in the hybrid configuration. Further, the amount of sticky sugars present in the flowers was markedly increased.

In at least one of the test grows, the geographic area runs rather cold in certain seasons and due to the lower excess heat output of LEDs, supplemental heating needs to be used for LED-ONLY grows. The hybrid growing method solved the heating issue due to the heat generated by the 400W HPS.

Conclusion

Hybrid lighting systems, consisting of High Pressure Sodium (HPS) and full spectrum Light Emitting Diode (LED) grow lights, can be used together to grow and flower plants – outperforming HPS-only lighting systems. In hybrid systems, a smaller HPS lamp (400W) than normally used (1000W) may be supplemented with LED grow lights. The resulting crop yield of the hybrid lighting system is superior to the HPS-only system due to extended physical coverage, as well as expanded spectrum coverage provided by the LEDs. Flower quality and quantity are increased over HPS-only grows, and power consumption is reduced by up to 50%. In the hybrid systems, excess heat is reduced by up to 50%, saving additional money on electricity, as well as reducing losses in evaporation of water and costly nutrients. LEDs last for over 50 grow cycles, reducing costs in replacement lamps (bulbs). Using hybrid grow lighting as opposed to LED-only grow systems in colder climates eliminates the need for supplemental heating.


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