315W CMH Economy (no bulb)

Description

Let’s look at the spectrum output of each lighting system and compare them.

The spectrum output of CMH, HPS, MH and Red/Blue LED grow lights compared to the suns output.

The Budget Red/Blue LED panel is primarily narrow band Red and Blue LEDs. This spectrum is proven to work but inspection of the plants is difficult and the benefits of a broad spectrum of light are now being realised.

The High Pressure Sodium bulb produces an efficient spectrum for growing but with only 5% blue the plants are likely to stretch.This is not ideal for growing indoors in confined spaces but has been tolerated in the past as it is a more efficient spectrum for growing.

The Metal Halide bulb emits a broad spectrum light and is suitable for growing from seed to harvest. However the relatively high amount of blue in the spectrum at 23% is more than needed. Increasing the amount of blue over 15% reduces the efficiency of the light for growing.

The Ceramic Metal Halide is a perfect spectrum for growing plants from seed to harvest. The level of blue light is ideal at 15% and the balance is red and green in equal measure. The addition of UV and Far Red in the spectrum delivers the closest match to the Suns spectrum.

The best Budget Grow Light Efficiency comparison

To give you a like for like comparison we used the same reflector, light hanging height, grow tent and testing method for each HID technology. We hung the Mars reflector at its manufacturers recommended hanging height. We have tested the Photosynthetic Photon Flux Density or PPFD output of each grow light and divided by the power consumed. The efficiency result can be compared just like the fuel efficiency of cars can be compared using kilometers per litre. Ceramic metal halide is comparable with the highest efficiency Blue/Red LED grow light Mars Hydro produce.

The grow light technologies have been tested for PAR light delivered to the grow area per kilowatt of electricity. Metal Halide is very low efficiency and High PRessure Sodium is the standard. The Mars Hydro Reflector LED panel is their most efficient model. The MGRO 315w CMH Economy matches the Mars Hydro for efficiency.

The best Budget Grow Light – running & fixture Cost comparison graph

We compare the three year cost of ownership for the the different systems including the orginal purchase price and running costs.

The High Pressure Sodium is the benchmark for PPFD output and the Metal Halide and Ceramic Metal Halide are multiplied by a factor to level the output of all the lights. For example 1.7 CMH systems are required to match the 600WHPS so that factor is applied to the CMH fixture and running costs so the two systems can be compared.

The three year running costs for the CMH is within a few percent of the running cost of the HPS or budget LED grow lights. As the CMH has a much more desirable spectrum it is clear that the CMH is the best overall choice for growing with HID or budget LED grow lights.

The costs compared for each fixture to deliver the same PAR average to a 1.2 x 1.2m (4×4) grow area. The costs for Metal Halide are very expensive due to it’s inefficiency. The HPS, CMH and budget LED panel are within a few percent of each other over three years growing.

The costs compared for each fixture to deliver the same PAR average to a 1.2 x 1.2m (4×4) grow area. The costs for Metal Halide are very expensive due to it’s inefficiency. The HPS, CMH and budget LED panel are within 2% of each other over two years growing.