Greenhouse lights: HortiPower vs Philips

In this blog post we are going to compare supplemental greenhouse lighting from HortiPower and Signify (formerly known as Philips).

HortiPower Grower is strong in its full adaptability of intensity (0-100%) and spectrum flexibility through software. This enables the grower to choose 1 light that can be used for many different use-cases through its software control.

Philips Greenpower has 84 different light models with fixed spectrums at different intensities and some of them are dimmable.

The Greenpower compact delivers a large output of light especially with versions that contain only Red and Blue colors. However its spectrum cannot be adjusted and its color combinations may lack other light which is still relevant for plants.

The information used in this article is retrieved from the official website and viewed at 9 October 2020.

Light output differences

Most greenhouses use supplemental light to the natural daylight that is coming in. Commonly used lights are HPS (Son-T) lights that consume 315W, 600W or even 1000W. These lights typically produce around 615, 1120 and 2100 μmol/s. Keeping the same or higher μmol/s is important when replacing HPS lamps.

HortiPower Grower can easily replace 315W and 600W HPS lamps and increase light intensity.

The Greenpower LED Toplighting can easily replace 315W, but its light intensity does not reach the 600W HPS equivalent. This means a higher quantity of lights need to be installed in order to reach a similar lighting level.

The Greenpower compact can replace the 1000W HPS lamps.

Dimmability

When you have more natural light coming in during bright and sunny days you may want to dim the lights so that overall the light levels for your plants are consistent. 

Natural daylight intensities differ significantly during a cloudy day or clear sky or inbetween seasons.

The HortiPower Grower can adjust intensity from 0% to 100%. It is perfect when a grower has climate computers and sensors that adjust light intensity frequently. With this intensity control the grower is also able to run dynamic lightscripts and have precision control on light intensity. And when the light is dimmed the power consumption also decreases.

For the Greenpower LED toplighting linear (regular output) it is not clear from datasheets it if is able to dim. The high output version and compact version cannot dim to 0%, but is able to dim to 10%. To use this you would need the additional grow wise control.

Colors, spectrum choice and efficiency

The plant-centric light spectrum contains all colors from 400-800nm which contains e.g. blue, green, red, far red. And in this spectrum white is a combination of these colors. Each color can influence different growth and development processes in the plant. The ratio of these colors in natural light vary based on geolocation, season and even time. For example, during the afternoon there is a lot more far red in the natural light than during noontime. Some research suggests that this tiny bit of far red in the afternoon can support cold-resistance in a crop such as tomato, light might help to trigger the tomato to prepare for cooler temperatures at night. While traditionally LED grow light was mainly red and blue, there is increasing research that shows that e.g. green can also be absorbed by plants and used during photosynthesis.

The relative efficiency for plant-centric light is highest in Deep Red and Blue, whereas Green, Far Red and White score relatively low. It is therefore tempting to optimize for energy efficiency and cut out all other colors. However some research suggest that after a certain threshold of Red and Blue, the impact and relevance of other colors become a much more important aspect than only increasing intensity.

HortiPower Grower uses all colors such as Deep Red, Blue, Green, White and Far Red. These colors are then individually adjustable so it can provide any combination based on crop, growth goals, growth stage, season or daytime. This is a significant benefit for the grower since you can use a spectrum that you like, and update it when needed in order to take advantage of the latest science and insights from other growers elsewhere with slightly different spectrums.

The Greenpower top lighting limits it spectrum choice to certain colors in combinations of 2 or 3 colors. E.g. Deep Red and Blue or Deep Red, White and Far Red. Since Blue and Deep Red score high in plant-centric light the relative intensity and efficiency are high but less diverse. Hence a 3.6 umol/J score for the Greenpower Compact. Obviously if the fixture excludes certain colors it is not possible to adjust or add colors without replacing these fixtures.

Cooling

Cooling is important for horticultural lights. While the light beam of LEDs itself is cool, the LEDs generate heat on the printed circuit board. This heat has to be well dissipated otherwise it impacts the lifetime of the LEDs. Less heat from light in general is better since it allows the grower to control heat specifically through its heating installation, rather than dealing with residual heat from light.

The Greenpower linear fixtures goes up to maximum 315 watts per linear light, whereas HortiPower Grower can go up to 650 watts per linear light. The key difference is that the Grower uses a different thermal design which significantly increases the heat dissipation surface, hence it is able to double the wattage without getting into heat issues.

The Greenpower compact is a different form-factor and goes up to 645 watts with heat dissipation through its heatsink upwards and sidewards. Ideally heat is dissipated upwards since that is the natural heat tendency.

Lifetime

All fixtures have a lifetime of 36.000 hrs.

Voltage input

All fixtures have different voltage input ranges

IP Rating

All fixtures have IP66 rating

Different hardware variants

The Greenpower lights come in 84 different variants, mainly with differences in power wattage and fixed spectrum. Once a fixed spectrum is chosen it cannot be adapted.

The HortiPower Grower is dimmable and therefore can adjust to different power wattages that are preferred by the grower at that moment. It also has a flexible spectrum so it can cover a wide range of spectrum choices. The hardware is made for flexibility and with the help of software it is an excellent choice to grow, adjust and optimize over and over again. With trends such as plant empowerment and data-driven cultivation this flexibility may benefit young plants, adult plants, the growers, scientists and many more.