Advice, opinions, suggestions

[Madtabman]

Hi guys. So I have a Maxibright Daylight 660w pro LED. I've been scrogging under it for 10 days now in veg. Im getting a maximum 600umols at canopy at 18/6. My thoughts are to increase umols by 50 then incrementally by 50 or so week to week if thy are happy. Now the light has a distance of 7-9 inches from the canopy at 50% power and they love it honestly I'm so surprised. But the problem I see is if I want to increase the umols for my last bit of strech. I have 2 options lower the light which I don't think is a good idea and raising the light and turning up the power to 75%. Now I just raised the light and upped to 75%. And they are now receiving 675umols maximum. But the light is so far away from the canopy like 50 inches. Which has me wondering a few things. Will the plants stretch increase now? Am I overthinking it and maybe I should have just left everything the way it was? Or am I doing it correctly and my job now is to monitor and slowly move the light up and down in order of what the plants want and are happy with?

 

[013]

don’t have light meter or know crap about umols but 50 inch spacing is wasted energy!

the team will jump in with more / better info

 

[Madtabman]

don’t have light meter or know crap about umols but 50 inch spacing is wasted energy!

the team will jump in with more / better info

Yes I have a light meter I dont care about wasted energy. I care about efficient light intensity and exposure. I'm now getting 720 umols at canopy level. At 46 inches.

 

[013]

wasted energy, wasted time, whatevs….

since light is their food…. which would be more effective? which would provide better coverage?, or which woukd penetrate the canopy? To feed them from great spacing distance or to feed them up close?

the further the plant is from artificial light source source the more output wattage required to illuminate them, the opposite of efficient light intensity

lets see if @Delps8 is available

 

[Delps8]

Hi guys. So I have a Maxibright Daylight 660w pro LED. I've been scrogging under it for 10 days now in veg. Im getting a maximum 600umols at canopy at 18/6. My thoughts are to increase umols by 50 then incrementally by 50 or so week to week if thy are happy. Now the light has a distance of 7-9 inches from the canopy at 50% power and they love it honestly I'm so surprised. But the problem I see is if I want to increase the umols for my last bit of strech. I have 2 options lower the light which I don't think is a good idea and raising the light and turning up the power to 75%. Now I just raised the light and upped to 75%. And they are now receiving 675umols maximum. But the light is so far away from the canopy like 50 inches. Which has me wondering a few things. Will the plants stretch increase now? Am I overthinking it and maybe I should have just left everything the way it was? Or am I doing it correctly and my job now is to monitor and slowly move the light up and down in order of what the plants want and are happy with?

There's no need to increase light that slowly. Check out my posting here.

How are you measuring PPFD?

50µmol is not much - that's about the change in PPFD when you move the sensor 1" vertically. In the post that I linked to, I theorize that growers think about plants the way we understand athletes train - it's a gradual process of overload and recovery. That's not how plants work.

With a mature plant, you should be able to jump your PPFD by 200µmol per day. Of course, you have to watch your plants to make sure that they can handle the new light level but cannabis' "light saturation point" is described as 800-1000µmol. That assumes that the grow environment is good and different strains may be different. I routinely grow autos and photos at > 1kµmol.

As hang height increases, PPFD drops but the PPFD map tends to even out. At 8", you're getting a lot of light in the center but it falls of pretty quickly once you move off center. The image below is from the manual for that light. It doesn't give a hang height but it does indicate that it's got a hot spot. The trick there is to raise the light but, as you're figuring out, the higher you raise the light, the lower the PPFD so, like everything else, it's a tradeoff.

50" is very high and you're only getting 675µmol. I would increase the power setting to 100% (or 90W% if you're concerned about running at 100%) and lower the hang height until you get 850µmol± on your grow. If things go well at 850, drop the light again until you're at 1k. For most grows that's about the limit and you're going to get a lot of flower at 1k.

If your plants curl their leaves or rotate them, like a Venetian blind, that's an indication off excess light so drop the light level a bit and let them straighten out.

It's no big deal for a leave to taco. I give my plants a lot of light and have also had a dimmer fail which pushed my light level from 1050 or so to about 1300. I noticed that the temp in my tent had shot up and, when I stepped in the garage, I knew something was wrong. I replaced the dimmer and it took an hour or two for the handful of affected leaves to return to their normal shape.

The balance is to get high levels of light on your canopy, across the entire canopy. That doesn't, necessarily mean across the entire grow space but you should do your best to have an even canopy that fills the tent so that "no photons hit the floor".

Plants in cannabis grows stretch, mostly, when growers don't give their plants enough light. And most growers don't give their plants much light. :-(

One of the "problems" with cannabis is that it looks great at modest light levels. The downside to that is that growers don't get the most out of their grows.

Growers lose more yield by not giving their plants enough light than they do by giving their plants too much light. That's not bold statement, really, because it's hard to damage a plant with an LED grow light because, if a plant is getting too much light, it will change the shape of its leaves to reduce the amount of light it's getting. If a grower ups the light and doesn't watch their plants, they'l taco a few leaves but the increase in yield just by turning up the dimmer is pretty amazing

I created this table from the cited paper:

Increasing average PPFD from, say, 650µmol to 850 increased yield by 4.9+4.7+4.5≈15% so if you turn up the dimmer, your 8 ounces will be >9 ounces.

But more light also gives a healthier plant that's easier to work with. Plants that don't get a lot of light will be tall and slender with lots of internodal space and a smaller number of large leaves. On the other hand, a plant that's been given lots of light will tend to be shorter, with more branches, and shorter internodal space. That means you will get more weed but they're also easier to work with.

This plant was really nice to work with. Very easy to manage, easy to get good light, etc. etc.

 

[bluter]

holy shit @Delps8 that's a deep dive. nice.

i do a big jump in power between veg and flip. but i have 2 rigs. my veg rig is underpowered though.

 

[Madtabman]

"50" is very high and you're only getting 675µmol. I would increase the power setting to 100% (or 90W% if you're concerned about running at 100%) and lower the hang height until you get 850µmol± on your grow. If things go well at 850, drop the light again until you're at 1k. For most grows that's about the limit and you're going to get a lot of flower at 1k."

I'm using a Phantom photo bio and I concentrate on the readings under the center of the light at canopy level and that's where it's at 675 umols right now.

My light only goes up in 25% intervals.
You see, so if I put it at 50% I'd have to have it about 5 inches from the canopy to get over 500 umols.
I have it at 75% now and didn't want to push them.
I get what your saying about getting it closer but 850 umols at the start of 3rd week of flowering? Still stretching a little?
@Delphs8

 

[Delps8]

holy shit @Delps8 that's a deep dive. nice.

i do a big jump in power between veg and flip. but i have 2 rigs. my veg rig is underpowered though.

Thank you, I appreciate that.

RE veg vs flower - based on Westmoreland's comments in his videos, I'm thinking that high PPFD in veg is more important than in flower because that's when the plant is building out the infrastructure. With more branches, I think you'll get more bud sites and, therefore, more flower. I haven't seen any data to support that, just a hunch.

 

[Roy Growin]

Thank you, I appreciate that.

RE veg vs flower - based on Westmoreland's comments in his videos, I'm thinking that high PPFD in veg is more important than in flower because that's when the plant is building out the infrastructure. With more branches, I think you'll get more bud sites and, therefore, more flower. I haven't seen any data to support that, just a hunch.

I'd agree with that - most fruits and flowers produce more when conditions are favourable in the veg phase rather than the bloom/fruit phase

 

[Delps8]

"50" is very high and you're only getting 675µmol. I would increase the power setting to 100% (or 90W% if you're concerned about running at 100%) and lower the hang height until you get 850µmol± on your grow. If things go well at 850, drop the light again until you're at 1k. For most grows that's about the limit and you're going to get a lot of flower at 1k."

I'm using a Phantom photo bio and I concentrate on the readings under the center of the light at canopy level and that's where it's at 675 umols right now.

Good, a PAR meter.

Based on the PPFD map from the manufacturer, if you're at 675 at the center, you're getting very little light at the edges, somewhere in the region of 350µmol. Does that check out with what your meter is reporting?

If that's the case, I'd look to super crop the center of the plant. That will let you drop the light and get more photons out to the edges and corners.

I sample the canopy. Here's data from a grow this year:

The grid pattern gives me an idea of how even the canopy is. In that case, it was pretty good.

And in late flower, from early 2023:

I start on the left and sample front to back so 24-26 are on the right edge of the tent.

If you're got a "record" function on your meter, that can be handy. I've used that feature on my PAR meter but will admit that I've settled on creating a note on my iPhone, putting it in dictation mode, and then just calling out the numbers - "eight seven five new line, one zero five five new line…"

Once I'm done recording the light values, I open the Note on my Mac and copy and paste the contents into Excel.

Sounds strange but it's really handy.

My light only goes up in 25% intervals.

You can fine tune PPFD by raising or lowering the light. Moving the light just 1" makes a difference.

You see, so if I put it at 50% I'd have to have it about 5 inches from the canopy to get over 500 umols.
I have it at 75% now and didn't want to push them.

You're not pushing them - you're feeding them.

By the time a cannabis plant is in mid-veg, it can use 800-1000µmol. Again, that depends on the grow and the strain so there's no doubt that plants will not be able to use that much light. I've seen two grows here on 420 where the plants crapped out at 500±µmol. In both cases, the plant wasn't being watered correctly and parts of the soil had turned hygrophobic. The key phrase is "if light it the limiting factor" so, if your grow is set up well, your plants will thrive at 800-1000µmol.

If I might suggest, do a 9 point sample. Start on the left and then sample the values in the back, the center, and the front. Then move to the center of the plant and sample back, center, and front. Put those in a spreadsheet so you can get a "picture" of the light values.

If you put them in a grid the way I've done in the first set of values, you can make a chart similar to the PPFD chart for your light. Here's one set of values and the surface chart (with settings) from Excel. That's what the light values are, looking down at the canopy from the light. For this set of data, you can see that it's really low in the back left.

Once you do your table, go to the Insert menu item, then "Chart", and select "Surface". Excel will draw a chart but it shows the back row at first. Right click on the chart and you'll be able to rotate the chart around so that it's easier to see.

I get what your saying about getting it closer but 850 umols at the start of 3rd week of flowering? Still stretching a little?
@Delphs8

Plants that are given lots of light don't stretch. They will grow taller because that what plants do but, if there's lots of light, they build out their branches and leaves.

This is the plant in data set #2. It's averaging 940µmol under a dedicated flower light. Red photons tend to make plants grow taller but this plant was only about 30" tall.

 

[Delps8]

I'd agree with that - most fruits and flowers produce more when conditions are favourable in the veg phase rather than the bloom/fruit phase

And it's ironic that so many cannabis sites recommend that PPFD is lower in veg than in flower. :-(

 

[Madtabman]

Ok thankyou so much you have given me so much to look at and to experiment with. I'm going to do some light adjustments. When they turn on tonight. I'm starting to question my choice of light now. I'm in 5x5 tent if there is a better one with better/even coverage I can get it after this harvest. This was the first LED I've ever used. This is my 3rd cycle using it. I also need to mention that on my last grow I suffered some terrible bleaching on some Epic Buzz phenos I was doing. It was my fault. They were telling me they didn't like it by twisting and things. But I didn't know what was going on. Im still learning. And thanks to guys like yourselves I'm learning more.

Ps if you have a better light in mind for a 5x5 that would be great. Everything else i use in there is AC infinity. But I don't have their light.

 

[Roy Growin]

Ok thankyou so much you have given me so much to look at and to experiment with. I'm going to do some light adjustments. When they turn on tonight. I'm starting to question my choice of light now. I'm in 5x5 tent if there is a better one with better/even coverage I can get it after this harvest. This was the first LED I've ever used. This is my 3rd cycle using it. I also need to mention that on my last grow I suffered some terrible bleaching on some Epic Buzz phenos I was doing. It was my fault. They were telling me they didn't like it by twisting and things. But I didn't know what was going on. Im still learning. And thanks to guys like yourselves I'm learning more.

Ps if you have a better light in mind for a 5x5 that would be great. Everything else i use in there is AC infinity. But I don't have their light.

I think both @Krissi Carbone and @Skunksta have trialled and reviewed lamps in similar sized environments
Maybe one of the two will pop in with a better answer

 

[Delps8]

Ok thankyou so much you have given me so much to look at and to experiment with. I'm going to do some light adjustments. When they turn on tonight. I'm starting to question my choice of light now. I'm in 5x5 tent if there is a better one with better/even coverage I can get it after this harvest. This was the first LED I've ever used. This is my 3rd cycle using it. I also need to mention that on my last grow I suffered some terrible bleaching on some Epic Buzz phenos I was doing. It was my fault. They were telling me they didn't like it by twisting and things. But I didn't know what was going on. Im still learning. And thanks to guys like yourselves I'm learning more.

Ps if you have a better light in mind for a 5x5 that would be great. Everything else i use in there is AC infinity. But I don't have their light.

You're very welcome.

Re. AC Infinity - I'm a big fan of their gear, except for the lights. They do some brilliant things, pardon the pun. Their Terraformer is a masterstroke, for example, but they market what I'd refer to as "value" lights vs "quality" lights.

That's in the lower end of the price range but their Ionframe EVO 10 is not in the value range. I run checked that light and also the EVO 8 only to the extent that I took the one of the PPFD values in the center and a value at the 4' mark. The light fall off was pretty high and I think it was higher than the % in a big Spider or Mars light.

Yeh, the spider dropped only 15% at 16" vs the EVO 10 which was 18% at 18". If the lights were at the same height, the falloff in the EVO would be great. When I check 12" hang height, the EVO 10 goes from 2001 to 1201 which is a 40% drop, The values for the Spider are 1989 to 1528 which is 23%.

The issue is that when you're putting 1000µmol at the center of the grow, with the EVO 10, you'll only be getting 600 at the edge vs. 77 at the edge with the Spider. There's a $219 price difference with the EVO10 being $999 vs $680 for the Spider.

Having an even PPFD map is just one factor that I look at when it comes to a grow light. Spectrum is fact, the ability to dismount the driver makes a difference as does remote control (both lights can be controlled using AC Infinity controllers).

I just picked out that the G1000 Spider light but haven't looked at Mars or other sellers' offerings in any depth. I prefer to buy either direct from the vendor or from Amazon but resellers can have some value add. On the latter point, we do have to accept that any advice from someone who stands to gain by you purchasing the products they recommend will tend to recommend products from which they will gain something.

It's just after 8 AM and I need to get my butt to my office and start typing programming words instead of "weed words". I haven't looked into the 5' market previously so I'll put some think time into this and do an update over the weekend.

One final thought - instead of a light for a 5' tent, which is a big beast of a light as well as being a single point of failure, there's a strong argument to use two smaller lights. Off the top of my head, they're smaller, so they're easier to maneuver, two lights give you some redundancy, and, finally, with two lights, it's easier to get a more even canopy especially since your grow will probably have an uneven canopy.

Would two lights, say 2' x 4' be an acceptable approach?

 

[Madtabman]

You're very welcome.

Re. AC Infinity - I'm a big fan of their gear, except for the lights. They do some brilliant things, pardon the pun. Their Terraformer is a masterstroke, for example, but they market what I'd refer to as "value" lights vs "quality" lights.

That's in the lower end of the price range but their Ionframe EVO 10 is not in the value range. I run checked that light and also the EVO 8 only to the extent that I took the one of the PPFD values in the center and a value at the 4' mark. The light fall off was pretty high and I think it was higher than the % in a big Spider or Mars light.

Yeh, the spider dropped only 15% at 16" vs the EVO 10 which was 18% at 18". If the lights were at the same height, the falloff in the EVO would be great. When I check 12" hang height, the EVO 10 goes from 2001 to 1201 which is a 40% drop, The values for the Spider are 1989 to 1528 which is 23%.

The issue is that when you're putting 1000µmol at the center of the grow, with the EVO 10, you'll only be getting 600 at the edge vs. 77 at the edge with the Spider. There's a $219 price difference with the EVO10 being $999 vs $680 for the Spider.

Having an even PPFD map is just one factor that I look at when it comes to a grow light. Spectrum is fact, the ability to dismount the driver makes a difference as does remote control (both lights can be controlled using AC Infinity controllers).

I just picked out that the G1000 Spider light but haven't looked at Mars or other sellers' offerings in any depth. I prefer to buy either direct from the vendor or from Amazon but resellers can have some value add. On the latter point, we do have to accept that any advice from someone who stands to gain by you purchasing the products they recommend will tend to recommend products from which they will gain something.

It's just after 8 AM and I need to get my butt to my office and start typing programming words instead of "weed words". I haven't looked into the 5' market previously so I'll put some think time into this and do an update over the weekend.

One final thought - instead of a light for a 5' tent, which is a big beast of a light as well as being a single point of failure, there's a strong argument to use two smaller lights. Off the top of my head, they're smaller, so they're easier to maneuver, two lights give you some redundancy, and, finally, with two lights, it's easier to get a more even canopy especially since your grow will probably have an uneven canopy.

Would two lights, say 2' x 4' be an acceptable approach?

The thing is I'm a big scrogger so I don't really have an issue with uneven canopy. And the other thing is that I'm hoping to move into a bigger area and i'm not sure of the size of area yet. So I'm thinking that in the future I'll may be buying another light the same as the one I'll be using in the 5x5. If that would be the right aproach I'm unsure about that?
So my set up right now is the 5x5 tent, Autopots using Coco and air bases, (I'm not fan of the Airdomes and the pH FLUCTUATIONS they cause at the rootzone IMO) 69pro controller, Cloudline S8 pro, Cloudforge T7 Gen 2 humidifier. 2 x Cloudray S6 Gen 2 Oscillating fans. And one 9 inch wall fan connected to the top of the tent facing down to the canopy. I'm new to AC Infinity and this is my first Cycle using anything by them. The gear is awesome apart from the inline fan is louder than my previous fan, if I ever whack it up to full blast, which is rare.
The Maixbright Daylight 660w Pro I've had for a couple of years now. IMO I'm using the best of the best right now apart from my light. A couple of lights that someone mentioned to me was called a "Diablo" or "Scorpion"or something. I've never even seen one of these and know anything about them. There's so many and dont know if either of them are compatible with my controller or even if that is necessary