Gavita 1930e vs gavita de

Apalchen said:

Hmm mind explaining ir to me a bit, I guess I could google but gotta go strip a room for the next 8 hours lol. Where does it fall on that scale like 700? So would those far red flower initiating pucks or strips work to do the same thing and if so I wonder how many you need to efficiently cover a 5x20 row?

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Ya the initiator pucks and booster boards should do the job. That being said I've never used those booster boards but it's on my list to try. Honestly you know who knows way more about this than me from real experience is @Grow Lights Australia @Prawn Connery @Rocket Soul

Apalchen said:

Hmm mind explaining ir to me a bit, I guess I could google but gotta go strip a room for the next 8 hours lol. Where does it fall on that scale like 700? So would those far red flower initiating pucks or strips work to do the same thing and if so I wonder how many you need to efficiently cover a 5x20 row?

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Why I want to run it is 660nm and 730nm together basically speed up photosynthesis more than the individual sum of those photons normally would. Plus IR drives cell expansion according to Bruce Bugbee so that's seems relevant. Lol.

the infrared signals the Phytochrome proteins. Cannabis uses Phytrochrome to know when to flower so high amounts of IR the more signalling to flower. At least that's the way I understand it.

Aeroknow said:

Only thing I trip out on is it seems the buds take longer to finish compared to under DE. Why i dunno.
But other than that, they seem to be a direct replacement for 1000W DE. I haven’t quite hit the same numbers yet that i get running DE at 1150W though.
They do kick ass.

oh yeah. Now that my AC’s don’t need to work as hard, def needed more DeHu. Totally worth it though.

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I would agree with both the answers below. I'm not sure about the afterglow, but there's also a pre-glow with HPS where it takes a few moments to heat up and starts to glow deep red and then orange before the light finally changes to its familiar pink-orange glow. I don't know how much difference that makes if any.

Rocket Soul said:

The most likely contender is missing far red on the led fixture, speeds up flower a bit. Some even say that the HPS "afterglow" could work a bit like people doing end of day treatment with far red. Not too sure on that one.

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MidnightSun72 said:

white LED
View attachment 4934661

vs Gavita DE
View attachment 4934660

I think the reason they finish faster under gavita is that the gavita is throwing an extra 400ish PPF of IR. So I think as a result of the IR signalling early finish.
Most of Bruce Bugbees info is kind of saying that IR photon should count towards the par range. So I think in reality the gavita still gives off more useable light. And probs why your yields haven't been better with the LED on a per light basis. But my possibly be better on a watt for watt basis. Albeit you are spending like 300W less per fixture going with LED. And there other advantages like being able to grow into the space under the lights and not e to avoid it for heat reasons.

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What we do know is that Far Red should definitely be counted in PAR readings as it has a noticeable effect on photosynthesis (Emerson Effect when combined with Red) and photomorphogenesis (accelerated flowering). @Prawn Connery first noticed the effects when running Nichia CRI90 LEDs in a grow room that had been using 600W SE HPS lamps. The Nichias had higher levels of Far Red, and he noticed that flowering times on typical 8-weeks strains were reduced by a few days. This is the typical spectrum of those 600W SE lamps that most growers were (and and still are) using around here.




The HPS spectrograph that @MidnightSun72 posted has a lot more Far Red in it, but the one above also has a decent amount of Far Red. It may not look like much, but it is more than typical CRI80 3000K and 3500K LEDs. A lot of the Far Red has been cut off at around 780nm where the spectrometer reading ends.

I can't find the Gavita 1930e spectrum but there do not appear to be any Far Red diodes in it. My understanding is the fixture itself is not that efficient compared to other LED fixtures, which makes sense as they appear to be using 3535 diodes (3030 whites are more efficient) packed close together and behind a glass or plastic sreen, so they will get hot which hurts efficiency. The 660 monos are the exception as they are generally very high PPE diodes. Those blue coloured diodes are not UV so the extra 450nm blue may not help with yields or flowering times but I'm just guessing until I see the actual spectrum.

Far red is somewhat tricky since it has several effects on the plant:

Emerson: far red + photo red; seems like total photosynthesis when both wavelengths are present is higher than what it would be by measuring total photons given. A kind of synergy effect. But I haven't seen the science of it for cannabis, especially in flowering. But there seems to be some references that this happens mainly when total light levels and photosynthesis are low, at higher light levels like cannabis flowering it's almost nothing.

But all the other effects are still in play:

Flower inducing: seems like it favors the flower response, speeding up flower a bit. But if it's not well balanced it can speed it up so much that the early harvest means some yield reduction.

End of day treatment: pr/pfr switching is what the plant uses for knowing when it's time to shut down and sleep. In normal conditions far red is very high at dusk, higher than 660nm, giving the plant a signal to go to sleep quicker by about 2 hours compared to no far red. Some use this to flower quicker, some use it to give the plant a couple of extra hours of daylight for more yield.

Shade avoidance: high far red, compared to photored, also triggers shade avoidance syndrome: stretch and yield lost. This happens as an adaptive response to far red being high in shady conditions. Best to be avoided, one of the reasons you want things to balanced.

Offset to uv: seems like far red and uv to some extent of set each other's morphological reactions; blue and uv shrinks leaves, far red increase size; far red stretches and uv inhibits stretch. Not sure if it is on anymore level than this.

The key seems to be to balance all things out and remember that a little is a lot.

i think i have noticed a slight reducution in flower times even when compared to sodium when using led + far red/730nm + EOD, an approx 11 week strain that i know well finishes closer to 10.

grotbags said:

i think i have noticed a slight reducution in flower times even when compared to sodium when using led + far red/730nm + EOD, an approx 11 week strain that i know well finishes closer to 10.

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Is it only far red or far red + uv? Uv is another factor in bud finishing time. I know @nachooo done a lot of work between breeding and lighting, he has a few sativa's finishing in 56 days I believe, but that's with far red+ eod + uva and b + shorter day cycles, 10-11h.

Rocket Soul said:

Is it only far red or far red + uv? Uv is another factor in bud finishing time. I know @nachooo done a lot of work between breeding and lighting, he has a few sativa's finishing in 56 days I believe, but that's with far red+ eod + uva and b + shorter day cycles, 10-11h.

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just far red up untill now, far red + uva is current so no data/hunches yet...

Well I already dropped almost 10k on only 8 lights . Who knows what will happen, I’m just gonna hope the engineers from the previous fixtures (de and 1700) are still there because that’s where my trust in the brand is coming from. I nerded out for weeks comparing bar fixtures from every where lol and then last minute kinda decided on these.

The thing the pushed me that direction more than anything might be stupid but it was that damn video of the guy pouring dirt on his fixtures on YouTube. Now I know you would never pour dirt on a fixture but over 5 years I guarantee there is enough dust from coco to have the same effect in my garden. And I don’t think you can get that conformal coating clean that is used on most lights. Hell right before I left home I thought I’d made my mind up to buy loriflux cause they were local company and I know a few guys killing it with them. They have no conformal coating which I thought would be a good choice vs sticky coating, but then I did some research and if you spray or fog rooms to clean between runs, burn sulphur or anything like that unprotected chips get damaged. So at that point I felt like it was buy a sticky coating that basically holds dust or have diode wear from IPM and cleaning. I had seen some videos of the 1930e and thought it looked cool but at $1399 retail it wasn’t even on my list. So I kinda just decided on the way to the store to say fuck it here is a deposit (what I was bringing to buy loriflux) order me 8 of the 1930e.

I do believe they will penetrate more than some other fixtures so if I need more or to add back in some de to get where I wanna be I’ll just have to do it.

Couldn’t figure out where that smacking head emoji was for after my first sentence of last post was, lol.

Cant wait to see what these light will do for you.... I'll be watching

oswizzle said:

Cant wait to see what these light will do for you.... I'll be watching

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Thanks man I just picked em up, but it will be prob 3 weeks or so before they have plants under em, I got to finish this run out.

I didn’t want them to get dusty in my garage so I left the bag on but grabbed a few pictures.


Heat sink


Came double boxed

I know with LED's penetration can be an issue compared to DE bulbs, but everyone I see running these 1930e's just hang them at the same height as their DE lights and don't move them throughout the grow. I wonder how they are able to do this. One of the best things I love about my DE lights is they stay in a fixed position, never have to move them. I assume these 1930e's are the same?

Are you going to do the entire room with these or just swap out half the DE's in each of your rooms. I saw a video of a room running both the Gavita De's along side the 1930's... apparently they can be daisy chained together and run off the same controller.

2klude said:

I know with LED's penetration can be an issue compared to DE bulbs, but everyone I see running these 1930e's just hang them at the same height as their DE lights and don't move them throughout the grow. I wonder how they are able to do this. One of the best things I love about my DE lights is they stay in a fixed position, never have to move them. I assume these 1930e's are the same?

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At first I only swapped out half my DE’s with the 1930’s to see what was up. I have the EL2 so i was able to still run the DE’s at 1150W on one zone and the 1930’s on another, at only 100%. I’m not sure what would happen if you try to run the led’s at 115%.
Then I ran them both at only 100%, same crop, two seperate sides. One side DE’s the other 1930’s. yielded identical. So i replaced the other half.

I have 12’ ceilings. My DE’s were hung 1’ below.
My 1930’s are around 14” below. Same spread, roughly 4’x6’. Pretty much the same yield.

2klude said:

Are you going to do the entire room with these or just swap out half the DE's in each of your rooms. I saw a video of a room running both the Gavita De's along side the 1930's... apparently they can be daisy chained together and run off the same controller.

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Yeah with the right cable adaptors you can run them together. But right now im switching out one room with all these. I had 6 de 1k fixtures and I was stretching out the coverage to 5x6 areas for each fixture. I got 8 of these and I’m gonna cover 5x20 rows with them. 4 fixtures per row with 2 rows. I guess ideally I should have bought two more fixtures and ran them the other direction, id have been lighting my walkway though. I might still add a couple more after I figure out the air conditioning needs. I want to buy the bontanicare rolling tables and move the plants to the middle of the room but that’s a run or two away.

Aeroknow said:

At first I only swapped out half my DE’s with the 1930’s to see what was up. I have the EL2 so i was able to still run the DE’s at 1150W on one zone and the 1930’s on another, at only 100%. I’m not sure what would happen if you try to run the led’s at 115%.
Then I ran them both at only 100%, same crop, two seperate sides. One side DE’s the other 1930’s. yielded identical. So i replaced the other half.

I have 12’ ceilings. My DE’s were hung 1’ below.
My 1930’s are around 14” below. Same spread, roughly 4’x6’. Pretty much the same yield.

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Did you have to buy some kinda adaptors to get them to work with the gavita controller? I haven’t messed with them yet I know it should be simple but I did notice that the plugs on the cables are bigger than the interconnect cables on the de fixtures, almost like phone jack size for de and Ethernet size for led.

Apalchen said:

Yeah with the right cable adaptors you can run them together. But right now im switching out one room with all these. I had 6 de 1k fixtures and I was stretching out the coverage to 5x6 areas for each fixture. I got 8 of these and I’m gonna cover 5x20 rows with them. 4 fixtures per row with 2 rows. I guess ideally I should have bought two more fixtures and ran them the other direction, id have been lighting my walkway though. I might still add a couple more after I figure out the air conditioning needs. I want to buy the bontanicare rolling tables and move the plants to the middle of the room but that’s a run or two away.


Did you have to buy some kinda adaptors to get them to work with the gavita controller? I haven’t messed with them yet I know it should be simple but I did notice that the plugs on the cables are bigger than the interconnect cables on the de fixtures, almost like phone jack size for de and Ethernet size for led.

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Nope. The only difference is in the connectors on the interconnect cables. The 1930’s use rj45’s.
You could, if the lengths are still good, snip off the old rj12/14 and crimp on rj45’s. Just make sure the wires are centered in the connector.
My old ones i made for the DE’s were not long enough so i bought a roll of 6 Conductor 28AWG flat cable off amazon and crimped on rj45’s. You don’t even need 6 wires but what the hell.
Easy peasy.
The cat6 cables they ship with weren’t long enough. If they came with 10’ cables they would have worked.

If those cat6 cable lengths don’t work for you and you make custom length ones like i do, make sure and put one of those ferrites before the first fixture in the chain.

Aeroknow said:

Nope. The only difference is in the connectors on the interconnect cables. The 1930’s use rj45’s.
You could, if the lengths are still good, snip off the old rj12/14 and crimp on rj45’s. Just make sure the wires are centered in the connector.
My old ones i made for the DE’s were not long enough so i bought a roll of 6 Conductor 28AWG flat cable off amazon and crimped on rj45’s. You don’t even need 6 wires but what the hell.
Easy peasy.
The cat6 cables they ship with weren’t long enough. If they came with 10’ cables they would have worked.

If those cat6 cable lengths don’t work for you and you make custom length ones like i do, make sure and put one of those ferrites before the first fixture in the chain.

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The interconnect cables between fixtures should be fine length wise for me. But I’m wondering how to actually connect to the controller. Now I have a cord running from controller to a splitter at that splitter my interconnect cables plug in, but unless it was the wrong splitter I tried earlier I don’t think these interconnect cables plug into it.

Apalchen said:

The interconnect cables between fixtures should be fine length wise for me. But I’m wondering how to actually connect to the controller. Now I have a cord running from controller to a splitter at that splitter my interconnect cables plug in, but unless it was the wrong splitter I tried earlier I don’t think these interconnect cables plug into it.

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So yeah, all you have to do is crimp on an rj45 connector to switch it over. You could then crimp on an rj11,rj12, or rj 14 and back to rj45 and so on. Both fixtures use the same wires, just different connectors.

If you are confused i can snap some pictures one of these days.

Rocket Soul said:

Far red is somewhat tricky since it has several effects on the plant:

Emerson: far red + photo red; seems like total photosynthesis when both wavelengths are present is higher than what it would be by measuring total photons given. A kind of synergy effect. But I haven't seen the science of it for cannabis, especially in flowering. But there seems to be some references that this happens mainly when total light levels and photosynthesis are low, at higher light levels like cannabis flowering it's almost nothing.

But all the other effects are still in play:

Flower inducing: seems like it favors the flower response, speeding up flower a bit. But if it's not well balanced it can speed it up so much that the early harvest means some yield reduction.

End of day treatment: pr/pfr switching is what the plant uses for knowing when it's time to shut down and sleep. In normal conditions far red is very high at dusk, higher than 660nm, giving the plant a signal to go to sleep quicker by about 2 hours compared to no far red. Some use this to flower quicker, some use it to give the plant a couple of extra hours of daylight for more yield.

Shade avoidance: high far red, compared to photored, also triggers shade avoidance syndrome: stretch and yield lost. This happens as an adaptive response to far red being high in shady conditions. Best to be avoided, one of the reasons you want things to balanced.

Offset to uv: seems like far red and uv to some extent of set each other's morphological reactions; blue and uv shrinks leaves, far red increase size; far red stretches and uv inhibits stretch. Not sure if it is on anymore level than this.

The key seems to be to balance all things out and remember that a little is a lot.

Click to expand...

Hey mate, good to see ya! You're right about the Emerson Effect being more pronounced at lower PPFD levels, but if memory serves me correct, those tests were conducted on lower PPFD plants and not cannabis, so it may stand to reason that the effect is greater at higher PPFD levels depending on plant species. I'm speculating, but I think I've read somewhere else that it still has an effect at higher PPFD levels. I'll have to go and research now . . .

Shade avoidance is something that can be harnessed and is not "best avoided" when you are trying to promote larger leaf area (as opposed to greater internodal length), as large leaves capture more photons. Actually, even longer internodal length can help with yields if it means better light penetration into the lower canopy. I have seen scientific tests where this was cited as being a probable cause for higher yields in cannabis species when compared to LED lighting with no far red. In fact, I think it was a Bugbee study – again, I'll have to come back to this.

Yes, UV can offset far red shade avoidance to an extent as it opposes cell expansion (far red shade avoidance promotes cell expansion). But I need to mention that when I first noticed the faster flowering times under the Nichia LEDs, I was comparing them to HPS and neither of the two light sources (LED, HPS) had any significant amounts of UV or near UV. (SPAM alert) Our new boards do have UVA and near-UV – as well as over 9% far red – and all reports are that flowering times are reducing by up to 10%.

I've actually been telling growers to run higher amounts of far red through ALL hours of flowering – including SOD and EOD – as red:far red ratios of typical LEDs is up to 10:1 or more, whereas sunlight is typically 1.3:1 and you don't normally see much stretch outdoors (although there is much more UV around).

Just my 2c

2klude said:

Are you going to do the entire room with these or just swap out half the DE's in each of your rooms. I saw a video of a room running both the Gavita De's along side the 1930's... apparently they can be daisy chained together and run off the same controller.

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Here’s those pics i told you I would take this morning. Obviously with the lights on

Pots of dirt. Megacrop and ph down only.