The yield is about the same as under HPS for equal PAR values, with everything else being kept the same. Can you tell me what the average PAR value under your LEDs looks like?
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What would you recommend as the ideal plant height to grow with high powered LEDS (e.g., 400w+)? Veg until 1’ tall then throw into flower? 1.5’? 2’?
Is there an optimal size due to penetration, or a recommended growing style?
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That depends on the beam angle (which may vary greatly between fixtures), and is also strain-dependent, with some strains being capable of handling higher PAR levels than others. As a general rule, 2 ft is a safe distance in most cases during flowering. Usually, the plants’ reaction is telling (photo bleaching is a sign of too much light).
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Hard to have a hard and fast rule on size wrt penetration - that is also highly dependent on beam angle.
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Energy efficacy is one area of superiority over HPS/MH that you mentioned and most lighting companies push and promote this metric. How are companies improving this value currently and how much of an improvement over the current state of the art do you expect to see in the next 5 years?
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I stopped by your booth at CannaGrow Expo last weekend and saw some new prototypes for racks to hold a bunch of GroBars. Do you have any more info on those that you can share?
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By using more efficient LED packages and also by introducing more efficient heat management techniques. The current state of the art LED products are at over 2 micromole/J in efficacy (which is better than any HID fixture), even when using passive cooling. Without active cooling, it’s tough to exceed 2.2 umol/J though. However, active cooling can add another 10% in efficacy even though it makes things worse in terms of reliability or facility infrastructure. I expect to see the 2.5 umol/J value achieved within 5 years.
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We are actively developing those and plan to carry them in the near future - will keep you posted.
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I was also really interested in your comment on spectrum flexibility. What is VividGro doing to introduce a flexible spectrum and have you tested or researched any benefits with such a feature?
Great AMA!
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I have used a variety of LEDs and one thing that has stood out is the ratio of 3 and 5 watt diodes. You have some that are strictly 5 watt diodes and others with 3 watt and then a blend.
Is there a true benefit of having a unit with only 5 watt diodes ? Or, why some have the ratio and others do not ?
I would assume the different watts would effect the PAR values as well.
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I experimented with flexible spectra 6-7 years ago. The problem there is that there are always “idling” LEDs, which rises the acquisition cost too much. Also, there is no clear consensus as to how many more spectra beyond 2 are really necessary. So at least for now, we are sticking with 2 fixed spectra - one for veg and one for flower.
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@VividGro I was introduced to an article written by Bruce Bugbee and Jacob Nelson; have you read it, and do you have any recommendations for other journal articles on the topic?
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The ratio of wattages is usually due to product cost optimization efforts. Higher wattage per LED means lower product cost but also lower efficacy, especially in the case of blue LED chips. So people try to achieve a balance between cost/performance and efficacy.
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The LED efficacy values in that article are 3 years out of date - 2.0 umol/J is the new 1.7 when it comes to LED fixture efficacy these days. At the same time, the HPS ones haven’t really moved since.
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Do you see any improvements in lifespan in LED lighting on the horizon, or is the lifespan already close to as good as it will get?
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What have you seen with LEDs that reach into the UV or infrared spectrums?
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LED lifespan has essentially flattened, so barring any new technology breakthroughs, not expecting to see much of an improvement there. As it is though, it’s very competitive wrt any incumbent lighting technology.
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The obvious thing with those is a drop in PAR efficacy (since UV and IR are not photosynthetically active). The potential added benefits are bactericidal effect and potentially better plant growth but haven’t seen any good quantifications there yet.
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In a similar vein then, have you seen any benefit to green LEDs?
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Thanks! Any more recent articles you recommend?
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