Talking about growing indoors, and yields per crop, growers usually use those HPS lamps (high pressure sodium) that promise the best results. Lighting industry offers multiple possibilities: lamps for flowering, lamps for growing phase, mixed lamps (for all cycle growth). Sometimes the quantity of lamps, makes it difficult for growers to choose wich one it's better. In this chapter we will analize different HPS lamps with a luxmeter (to offer a real meassure under same conditions). Now it's time for growers to choose wich one is better, our results are here:
All tests here described have been done keeping the same reflector, ballast, and distance between lamp and luxmeter.
All products used for the test were new to obtain the best result possible.
Brands and models of 400w High Pressure Sodium lamps (HPS)
Brands and models of 600w High Pressure Sodium lamps (HPS)
Test Conditions:
400w Et Ballast
600w Et Ballast
Reflector: Adjust A Wings
Distance lamp - lux-meter: 76 cm
We decided to do the test with a distance of 76 cm, even being more than recommended distance plants-lamp, because lamp's perfomance drop is bigger when the distance lamp-focus is increased. In relationship with this data (nearly 70% of the future crop will come from 60-80 cm lamp distance, so it is logic to assure that a decrease on lamp's performance may generate a dramatically descent of the light production (so on a yield decrease).
Conclusion after test:
Although absolut values may vary slightly from one lamp to other (of the same brand and model), in these comparative we will notice significant differences between brands and models. If we want to get best performance, per cycle, we should use the HPS lamps it's giving us most lumens (of the optimal color temperature). Acording with what's wxplained, the HPS lamps that will give the best result will be all those called mixed spectrum (fro growing phase and flowering phase). Not only because they give a full range of light color, optimum for the whole cycle of the plant, and a increased lumen performance.
Luxmeter with Sylvania
Luxmeter with Phillips
Luxmeter with Soldiers Lighting
Made this comparative for those growers who want to have a refference, after a continuous use of lamps,before having a performance descent.
*Sant Yerbasi recommends checking brightness from the lamps once every cycle to prevent against yield losses.