Light %

[desplegado]

The stage of a cannabis plant is a handy guide but that's all. Cannabis is a light whore loves light. Give you plant as much light as it can handle and it will grow incredibly well.

The XS-1500 Pro will put out quite a bit of light and, at 16" hang height, you're at about 600µmol. I use word "about" because I don't have a PPFD map for that height so I'm looking at the one on the Amazon listing and the info here. 600 is considered the minimum amount of light that you should give a plant in flower. Why? Because.

That's the number that I think Bugbee provides and I know that DeBacco (You Tube) states that but DeBacco isn't a researcher. He repackages a lot of what Bugbee says but I haven't read anything of his that's not in synch with Bugbee and others.

An excellent source for this is from Bugbee student, Mitch Westmoreland, who published a couple of YT videos this Spring with some of the research that he did for his PhD. Every grower should watch at least one of his two videos. He lays out his research very well and it's pretty simple 0 give you plants at much light as they can tolerate with ambient temps up to the mid-80's. Do that through veg and into about the second week of flower. That will allow the plant to build out its infrastructure. Once you're in about week two of flower, if you want to maximize secondary metabolites, keep the temperature at the top of the flowers <=78°F.

OK, great info but it doesn't answer your question, because it depends on the grow. If you grow is "firing on all cylinders", you might be able to go to 100% and drop your hang height to 12". Per cocoforcannabis, that's going to get 950µmol± on your plant. That's quite a bit light but cannabis will handle more than that in ambient CO2.

On the other hand, you might drop the light to 14" and get canoeing of your leaves. If that's the case, you should check your grow and see what's not set up right. VPD could be off or not enough//too much wind in the tent or nutrient level too high. It could be a variety of things that, if they get adjusted, can allow you to feed your plants better.

But what I mean is when to I turn up the light% or woukd I even have to right now its at 50%

 

[Delps8]

Is ppfd next to the names and the lux it is or somewhat the top like the 10,000?

Lux values are the "10,000", "20,000" etc. in the column headers. The PPFD values are in the body of the table.

For the XS-1500 row, 10000lux is 145µmol. Just run your finger across that row and, each time you hit a new column, the table shows you the corresponding PPFD value.

 

[Delps8]

But what I mean is when to I turn up the light% or woukd I even have to right now its at 50%

That's not generating much light.

"have to" - there's no "have to". It's completely up to you. Cannabis will thrive at very high light levels but it will also grow well at modest light levels.

If your hang height is 16", a well setup grow will use 100% but the only thing I know about your grow is that you're giving it 50% of a Vipar at 16" so it might not be the case for your plants.

If I assume that your grow is in decent shape, I would advise you to turn up the dimmer dial from 50% to 70% and then watch your plants. If they can't tolerate that change, turn the dimmer back down and figure out why they can't tolerate that amount of light.

I sense some timidity/lots of caution. Fair enough. If there's too much light, the plants will tell you in a few minutes. They'll curl the edges of the leaves or take other action to get away from the light stream. No big deal. Just turn it down a bit.

 

[Delps8]

Is ppfd next to the names and the lux it is or somewhat the top like the 10,000?

Yup, you got it.

PPFD is across the row and the lux values are in the column headers.

 

[coreywebster]

U mean 100% at 16 in? There just starting to grow there pistils

Yeah sorry, typo.

Soon as you flip to flower 100%

 

[Mumbeltypeg]

That's not generating much light.

"have to" - there's no "have to". It's completely up to you. Cannabis will thrive at very high light levels but it will also grow well at modest light levels.

If your hang height is 16", a well setup grow will use 100% but the only thing I know about your grow is that you're giving it 50% of a Vipar at 16" so it might not be the case for your plants.

If I assume that your grow is in decent shape, I would advise you to turn up the dimmer dial from 50% to 70% and then watch your plants. If they can't tolerate that change, turn the dimmer back down and figure out why they can't tolerate that amount of light.

I sense some timidity/lots of caution. Fair enough. If there's too much light, the plants will tell you in a few minutes. They'll curl the edges of the leaves or take other action to get away from the light stream. No big deal. Just turn it down a bit.

Do plant reactions to light really happen in minutes? I didn’t know that.. that’s interesting, I have always adjusted and left overnight for reactions thank you I’ll have to play with this.

 

[larrypizzimp93]

If it’s 150 watts just understand the buds are gonna be small and not as dense. Especially if you have a plant with bad genetics. But I would keep it around 12 inches from top and if the top is yellowing, raise light (that’s light bleaching)

 

[desplegado]

If it’s 150 watts just understand the buds are gonna be small and not as dense. Especially if you have a plant with bad genetics. But I would keep it around 12 inches from top and if the top is yellowing, raise light (that’s light bleaching)

I think I have it at around 16-17 in

 

[Delps8]

Do plant reactions to light really happen in minutes? I didn’t know that.. that’s interesting, I have always adjusted and left overnight for reactions thank you I’ll have to play with this.

I've had a couple of instances of my grow light going to 100%. In each case, it was at that level for about 30 minutes before I noticed it. First time was when I switched on the second rocker switch on a Mars SP 3000. I didn't realize that I'd hit that button and, apparently, it bypasses the dimmer and sets the light to 100%. The other time was when the dimmer on my Growcraft failed and set the light to 100%. The Mars went to <1100µmol but the Growcraft went to almost 1300.

The only way I knew that there was an issue was that the temperature in the tent went up rapidly and since I have a Controller 69 in the tent, I could see the temp spike.

In both cases, the reaction was very rapid but both cases weren't just "a little bit too much light".

The leaves didn't canoe. Instead, they rotated around their petiole, similar to how a Venetian blind turns the slats. Fortunately, the leaves that were impacted started rotating back to normal orientation within about ½ of turning down the light.

One grow which got just a little too much light had a cola that bent, right near the top. It never straightened out, though.

Perhaps the issue that I hit was because the plants were getting gobs of light more than they could handle vs maybe just 100 or 200µmol more than LSP to which they might have reacted by canoeing. Don't know. Twice was enough.

 

[Delps8]

Yeah sorry, typo.

Soon as you flip to flower 100%

And drop the light.

At 12" that light is putting out <900µmol which is where cannabis is quite comfortable. The various charts that show giving cannabis 600-800µmol in veg - or worse yet, the silliness that the Photone site talks about - aren't research based. They're very conservative recommendations and/or ignorance.



I believe that's one of the reasons why Shane at Migro sells lights that put out modest amounts of photons. It perplexed me for a while but I saw it as a savvy business move - lower powered lights are cheaper to manufacture and most growers don't know the difference. I can understand that as a business strategy. But Shane also has done videos about "How much light does cannabis need?" and his recommendations were not in line with published research. The guy is an EE so he's got some smarts so something just didn't set right with me.

Then I watched Shane interview Bugbee about light (it's on YouTube). When Bugbee says get plants to 1kµmol, you can see Shane just stop. To me, he looks, honestly, shocked but he recovers and asks the question again, expecting a different answer. Bugbee comes right back saying do the ton. Shane expresses his surprise and moves on to another question.

OK, he honestly didn't know. Now he does. And he hasn't changed the design of Migro Aray lights.

The OP can leave his lights at 50% and will have a happy plant and cop a few ounces. On the other hand, if he turns up the dial, he'll probably more weed. For me, I'll be damned if I'm going spend 3 months of my life to grow 4 ounces of weed. I'm 67 years old (68 in a few months) so I don't have that many more grows left. Plus, I've put a shitton of money and time into my equipment and processes so, for me, if I don't get a pound out of a grow, I consider it a failure.

Again, it's how the grower wants to do it. I just hate to see people putting their heart and soul into a grow and getting a couple of baggies worth when they can lower the light a few inches and end up wondering "what do I do with all this weed?"


Two plants, one grow.

I'm not saying a grower will get this kind of yield just by turning up the dial but I am quite sure that if a grower doesn't turn up the dial then he won't get this.

 

[desplegado]

And drop the light.

At 12" that light is putting out <900µmol which is where cannabis is quite comfortable. The various charts that show giving cannabis 600-800µmol in veg - or worse yet, the silliness that the Photone site talks about - aren't research based. They're very conservative recommendations and/or ignorance.

View attachment 5413702

I believe that's one of the reasons why Shane at Migro sells lights that put out modest amounts of photons. It perplexed me for a while but I saw it as a savvy business move - lower powered lights are cheaper to manufacture and most growers don't know the difference. I can understand that as a business strategy. But Shane also has done videos about "How much light does cannabis need?" and his recommendations were not in line with published research. The guy is an EE so he's got some smarts so something just didn't set right with me.

Then I watched Shane interview Bugbee about light (it's on YouTube). When Bugbee says get plants to 1kµmol, you can see Shane just stop. To me, he looks, honestly, shocked but he recovers and asks the question again, expecting a different answer. Bugbee comes right back saying do the ton. Shane expresses his surprise and moves on to another question.

OK, he honestly didn't know. Now he does. And he hasn't changed the design of Migro Aray lights.

The OP can leave his lights at 50% and will have a happy plant and cop a few ounces. On the other hand, if he turns up the dial, he'll probably more weed. For me, I'll be damned if I'm going spend 3 months of my life to grow 4 ounces of weed. I'm 67 years old (68 in a few months) so I don't have that many more grows left. Plus, I've put a shitton of money and time into my equipment and processes so, for me, if I don't get a pound out of a grow, I consider it a failure.

Again, it's how the grower wants to do it. I just hate to see people putting their heart and soul into a grow and getting a couple of baggies worth when they can lower the light a few inches and end up wondering "what do I do with all this weed?"


Two plants, one grow.

I'm not saying a grower will get this kind of yield just by turning up the dial but I am quite sure that if a grower doesn't turn up the dial then he won't get this.
View attachment 5413703

I have lowered my lights to 12 in and put the light to 50 plants are looking ab the same prob could water bc I haven't watered in 3-4 days how much should I give them do you need pics of the plants to know I've only been doing 2 cups and upping it by the week I'm just new and don't k ow anything and can't find anything
I'm growing in a 5 gal bucket

 

[Delps8]

I have lowered my lights to 12 in and put the light to 50 plants are looming ab the same prob could water bc I haven't watered in 3-4 days how much should I give them do you need pics of the plants to know I've only been doing 2 cups and upping it by the week I'm just new and don't k ow anything and can't find anything
I'm growing in a 5 gas bucket

What were your settings before - hang height and dimmer %?

 

[desplegado]

What were your settings before - hang height and dimmer %?

Around 16-20 at 50

 

[Delps8]

Around 16-20 at 50

At 50% and 16-20", your plants are getting seedling levels of light. At 12" and 50%, they're getting about 450µmol which is early veg.

I don't know much of anything about your grow but a cannabis plant in early flower will be quite happy with the light output from that light at 100%. Per the PPFD map below, which is from the product listing on Amazon, that would give your plant(s) just under 900µmol.

When I check the Vipar website FAQ's, they state:

A: For seedlings, you should hang the lights 22 inches above the canopy. For the vegetative and flowering phase, you should hang the lights 12 inches above the canopy.

The assumption is that the light is running at 100% power.

If your plant has been getting, say, 450µmol and you turn the light up to 100% and give it 900µmol±, you might well "piss it off" so I would recommend that you take pictures of the plant (and post them here) at the current setting, then turn the dimmer from 50% to 70%. That will increase PPFD from 450 to about 630µmol. That's a decent jump in the number of photons and, if your plant doesn't like it, it will indicate as such by doing what it can to reduce the amount of light. Typical reactions are for leaves to "canoe" or "taco" but they will also rotate leaves to a vertical orientation similar to how a Venetian blind opens and closes.

The reaction can be very quick. I've had lights go to 100% power a couple of times and the leaves reacted within 30 minutes. You're just bumping up the dimmer so it won't be as quick (if at all) but you need to make the change and then see how the plants react. I suspect (and hope) you'll see no change but you should check the plants about ½ hour after the change and then every hour or so after that.

When to bump the dimmer setting? When you're going to be home for the day (assuming that's where your tent is located) and when you'll be able to check the tent every "once in a while".

Once you've got your plants to 70% (630µmol), the next step would be to go to 80%, check to see how they react, then 90%, etc. etc. I would recommend that you take photos of the plant(s) before you increase the dimmer setting and then take photos a little while later. If there's going to be any "photo-inhibition", the leaves at the top of the plant will be the ones to react the most because they're the ones closest to the light.

How does that sound?

It would be very helpful to see photos of your grow. I'm making assumptions that your plant(s) is healthy and that could be completely off base. Photos + grow info would add very valuable context.

 

[jimihendrix1]

I blast my seedlings, from day one. I figure if I lived at the Equator, and I was growing outside, they would get blasted from day one Even in North America, in the direct sun, they get blasted, from day one.
The SUN, at the Equator, is 2000umol+, and 108,000 LUX. They would also be getting blasted with UVA/b
I start seedlings under a 1000w Hortilux HPS at 24 inches, or a 1000w Hortilux Blue, at 20 inches, and let the plants, grow towards the light. I also keep a fan on, 24/7, so there is a constant breeze. Its usually directed between the top of the canopy, and the bottom, of the bulb. Temps are 78f-85f.
Im also not in a tent, but an open room/basement. Huge airflow/exchange. The trick to using large amounts of light, is a constant, fresh air exchange. IMHO, most so called light stress, is caused by inadequate fresh air exchange.

 

[EvilJ]

Amazon has a couple par meters ( not lux) under 100.00. It’s so worth the money, once I used it realized my light were wayyyyy to far. Same clones I’m running now have improved dramatically, node spacing is the biggest change. I was going by the manufacturers recommendations, boy were they off.

 

[desplegado]

At 50% and 16-20", your plants are getting seedling levels of light. At 12" and 50%, they're getting about 450µmol which is early veg.

I don't know much of anything about your grow but a cannabis plant in early flower will be quite happy with the light output from that light at 100%. Per the PPFD map below, which is from the product listing on Amazon, that would give your plant(s) just under 900µmol.

When I check the Vipar website FAQ's, they state:

A: For seedlings, you should hang the lights 22 inches above the canopy. For the vegetative and flowering phase, you should hang the lights 12 inches above the canopy.

The assumption is that the light is running at 100% power.

If your plant has been getting, say, 450µmol and you turn the light up to 100% and give it 900µmol±, you might well "piss it off" so I would recommend that you take pictures of the plant (and post them here) at the current setting, then turn the dimmer from 50% to 70%. That will increase PPFD from 450 to about 630µmol. That's a decent jump in the number of photons and, if your plant doesn't like it, it will indicate as such by doing what it can to reduce the amount of light. Typical reactions are for leaves to "canoe" or "taco" but they will also rotate leaves to a vertical orientation similar to how a Venetian blind opens and closes.

The reaction can be very quick. I've had lights go to 100% power a couple of times and the leaves reacted within 30 minutes. You're just bumping up the dimmer so it won't be as quick (if at all) but you need to make the change and then see how the plants react. I suspect (and hope) you'll see no change but you should check the plants about ½ hour after the change and then every hour or so after that.

When to bump the dimmer setting? When you're going to be home for the day (assuming that's where your tent is located) and when you'll be able to check the tent every "once in a while".

Once you've got your plants to 70% (630µmol), the next step would be to go to 80%, check to see how they react, then 90%, etc. etc. I would recommend that you take photos of the plant(s) before you increase the dimmer setting and then take photos a little while later. If there's going to be any "photo-inhibition", the leaves at the top of the plant will be the ones to react the most because they're the ones closest to the light.

How does that sound?

It would be very helpful to see photos of your grow. I'm making assumptions that your plant(s) is healthy and that could be completely off base. Photos + grow info would add very valuable context.

View attachment 5413852

I dont have pics of them rn and the light is off I will send pics of the plant when light turns on around 8-9 pm but here are pics before, I don't have any pics of the other 2

 

[desplegado]

At 50% and 16-20", your plants are getting seedling levels of light. At 12" and 50%, they're getting about 450µmol which is early veg.

I don't know much of anything about your grow but a cannabis plant in early flower will be quite happy with the light output from that light at 100%. Per the PPFD map below, which is from the product listing on Amazon, that would give your plant(s) just under 900µmol.

When I check the Vipar website FAQ's, they state:

A: For seedlings, you should hang the lights 22 inches above the canopy. For the vegetative and flowering phase, you should hang the lights 12 inches above the canopy.

The assumption is that the light is running at 100% power.

If your plant has been getting, say, 450µmol and you turn the light up to 100% and give it 900µmol±, you might well "piss it off" so I would recommend that you take pictures of the plant (and post them here) at the current setting, then turn the dimmer from 50% to 70%. That will increase PPFD from 450 to about 630µmol. That's a decent jump in the number of photons and, if your plant doesn't like it, it will indicate as such by doing what it can to reduce the amount of light. Typical reactions are for leaves to "canoe" or "taco" but they will also rotate leaves to a vertical orientation similar to how a Venetian blind opens and closes.

The reaction can be very quick. I've had lights go to 100% power a couple of times and the leaves reacted within 30 minutes. You're just bumping up the dimmer so it won't be as quick (if at all) but you need to make the change and then see how the plants react. I suspect (and hope) you'll see no change but you should check the plants about ½ hour after the change and then every hour or so after that.

When to bump the dimmer setting? When you're going to be home for the day (assuming that's where your tent is located) and when you'll be able to check the tent every "once in a while".

Once you've got your plants to 70% (630µmol), the next step would be to go to 80%, check to see how they react, then 90%, etc. etc. I would recommend that you take photos of the plant(s) before you increase the dimmer setting and then take photos a little while later. If there's going to be any "photo-inhibition", the leaves at the top of the plant will be the ones to react the most because they're the ones closest to the light.

How does that sound?

It would be very helpful to see photos of your grow. I'm making assumptions that your plant(s) is healthy and that could be completely off base. Photos + grow info would add very valuable context.

View attachment 5413852

So far I haven't seen a change in any of them as far as me changing it all the way to 100 and I can't do 60 or 70 it goes by 25 like 25,50,75,100

 

[J2M3S]

So far I haven't seen a change in any of them as far as me changing it all the way to 100 and I can't do 60 or 70 it goes by 25 like 25,50,75,100

Expected. Nothing changes overnight.

 

[desplegado]

Expected. Nothing changes overnight.

If there's to much it will tell me within a few minutes according to delps if it's to much