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Ask Me Anything with Dr. Emil Radkov from VividGro

VG_FADE

We’re hosting an Ask Me Anything event on Wednesday, November 1st, 2017 at 11am MDT with Dr. Emil Radkov from VividGro to answer your questions about LED lighting solutions.

About Dr. Radkov:
Celebrated horticultural and SSL technology expert Dr. Emil Radkov is Senior Agronomist and Director of VividGro, an LED innovator focused on advanced agricultural and horticultural LED solutions. Backed by an extensive technology and intellectual property portfolio includes nearly 400 LED technology patents, Radkov himself has authored over 40 patents related to horticulture and cannabis grow technology.

New grower? Established operation? No question is off-limits when it comes to optimizing your output with Dr. Radkov.

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This should be a great one!!!

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@VividGro What would you say are the five most important distinctions in comparing LED to HPS?

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In no particular order: less radiated onto the plants, better energy efficacy (for the top LED products), spectrum flexibility to suit better different growth stages, no danger of explosive failure and no mercury that can be released into the facility upon breakage.

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Meant to say “less heat radiated onto the plants”

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Also, less frequent re-lamping due to the longer life.

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I tried LED for one crop and the yield was way less, about 50%. What is your experience on yield?

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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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