understanding different grow lights
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HIGH PRESSURE sodium ( HPS ) lights have been a common choice among indoor growers for many decades and are still the most common type of grow light used in the commercial greenhouse industry .”
HPS
High pressure sodium ( HPS ) lights have been a common choice among indoor growers for many decades and are still the most common type of grow light used in the commercial greenhouse industry . They emit light mostly in the yellow to red range of the spectrum , 565-700 nanometres ( nm ). For reference , yellow light occurs at wavelengths between 560 and 590 nm , orange at wavelengths between 590 and 625 nm , and red at wavelengths between 625 and 700 nm . High pressure sodium lights usually last for spans of time around 10,000 hours ( though bulbs should be changed after 18 months of use even if they have not been used for the full 10,000 hours as the quality and quantity of light diminishes over time ), and burn between 25 and 30 per cent efficiency . The remaining energy emitted from the bulbs is released as heat , making the surface of these bulbs extremely hot ( some studies have shown surface temperatures of HPS lights as high as 450 ° C ). High pressure sodium lights should not be placed in contact or very close to crops , as they will burn the foliage . For safety reasons , they should not be in contact with anything flammable such as some types of shade material or paper . It should also be noted that in most large , commercial growing facilities like greenhouses , they are used as a supplement to natural light . Growers that opt to use HPS light as the sole source of artificial light are not giving their plants anything useful from the blue range of the spectrum .
HID
High-intensity discharge lights ( HID ), also known as gas or discharge lights , are commonly manufactured as metal halide ( MH ) or sodium vapour light ( HPS lights are also HID lights , but they are excluded here since they were discussed above ). These work by passing electricity through a gas-filled tube . High-intensity discharge lights offer the brightest light of any lights discussed in this article , so they offer the added benefit of allowing crops to be easily inspected . They were used by growers for many years since they are about 10 times more efficient than traditional incandescent lights , which are inefficient , burn hot , and offer little in the way of blue light . High-intensity discharge lights , while more efficient than incandescent lights , still emit a lot of heat . Among the HID light choices , HPS lights are roughly equivalent in terms of energy efficiency compared to MH bulbs , but they are more efficient in their photosynthetic value . Metal halide bulbs offer better light on the blue side of the spectrum than HPS do . Highintensity discharge lights also require large , bulky , and often costly fixtures to operate them , though the bulbs themselves are relatively inexpensive . They are not typically the grow light of choice for most hobbyist growers or growers who operate in relatively small growrooms . The technology , however , is old by today ’ s standards , and most current research is being directed towards light emitting diodes ( LEDs ) and sulphur plasma technologies . If HID lights are a practical or more economically viable solution in a certain situation , a combination of both MH and HPS lights may be advisable if the crops being grown are blooming or fruiting crops as opposed to foliage crops like edible greens . These can be operated at the same time or alternated , depending upon the stage of growth ; better results will likely result by using both in tandem . Though HID bulbs are not interchangeable with one another , conversion lamps have been available for some time , which allow you to achieve the spectral output of an MH lamp in an HPS fixture . Also , there are double-ended MH lamps that have been recently introduced to the market that can be used as a direct replacement in a compatible HPS fixture .
44 grow cycle