Should I choose LED lights or HPS Lights?

Before deciding on whether to go for LED or HPS lights, TLS has made the choice easy for you. All our rigs can be fitted with HPS and/or LED lights.

Each light fixture, be it HPS or LED, has a similar PAR light output and they utilise the same cabling. You can also have a hybrid solution where you combine LED lights and HPS lights on the same rig.

Before concluding on what gives the best value for money and the best grass growth, there is a lot to consider.

First of all, let us start with some basic light information.

The plant utilises light within the 400 through 700 nanometer range, called PAR, or Photosynthetic Active Radiation.

Whilst the “standard” PAR spectrum range is 400 nm to 700 um, there is a “Wider” PAR spectrum range of 315 – 800 nm

The Hortilux HPS lamps are providing the below light spectrum.

About 54% of light is in the PAR area and 46% in in Near Infra-Red range. The NIR range is heat radiation. The NIR light adds value In cold light by providing heat, and it also helps drying a wet turf. In warmer climate the NIR range adds unwanted heat and is a waste of energy and may cause damage to the grass.

Typical LED grow lights are made with a red/blue mixture of RB/LB 95/5. The lower light frequency, the higher the energy lever, and a light mixutres with high level of red makes very energy efficient LED lights.

TLS and Hortilux have be running tests at the World Horticentre on a typical warm climate grass (Bermuda) and a cold climate Rye grass to determine what light mixture works best for these grass types. Based on the test results we have created our own LED light mixture for the TLS Turfpal rigs.

Before we can select whether to use LED or HPS lights, we need to compare the efficiency on HPS versus LED lights.

Both lights fixtures need a driver unit to create light. The HPS light looses about 28% energy through the driver (heat) and the LED lights RB/LB 95/5 looses about 36% through the driver. For the 39% of the energy is converted to grow light and 33% is NIR, or heat. For the LED lights, all light is grow light. In other words, with an input of 1000W, the HPS lamp converts 390 watts to grow light and the LED lamp converts 640 watt to grow light. The LED lamp provides 64% more grow light per energy unit!

In other words, if your soil and air temperatures is sufficient, or on the high side, to secure good grass growth, you select a 100% LED rig.

If you need to add heat to equation you have several options:
1. Lighting rig with HPS light fixtures (33% heat radiated for every energy unit)
2. Lighting rig with LED light fixtures and infrared heating elements
3. Lighting rig with a combination of LED and HPS fixtures
4. Swap between LED fixtures and HPS fixtures (LED during the warm season, HPS during the cold season)

From the above, we would recommend 1., 3, or 4. The heat footprint of the HPS fixture is identical to the lighting footprint and there is no energy wasted on pure infrared heating elements.