Why are my plants so big?

This is my first grow, so I'm still trying to figure things out. Currently, I have 2 Critical 2.0 autoflowers growing in my 2x2 tent and I'm just approaching week 7. When I look at videos of autoflowers on youtube, almost all of the plants are way shorter and have way farther developed buds by week 7. I assumed I could fit 2 plants if they would be smaller, but mine have taken over the whole tent. I started LST at the beginning of Week 2 and I loosened the ties around week 5. And I only topped the further back plant to see how they would grow comparatively. Does anybody know why my nugs on the colas are so spread apart, and my plant seems so underdeveloped at 7 weeks? Is it just growing slowly? Am I lacking something? Any insight will be appreciated.

try to bend them over. It’s too late to do much else. Next time you need to train them more or else they will outgrow your tent.

how tall the plant gets before flowering depends on the genetics. You cant compare your auto grow to another auto unless it’s the same exact breeder…even then their will still be slight variations.

photos are easier to control in a small/tight grow space. The YouTube growers (I assume, I don’t really go on YouTube) hype up autos like they’re easier to grow. They aren’t easier, and they’re less forgiving.

There's a bunch of reasons plants get lanky...sometimes that's genetics (Sativa dominant plants get bigger than Indica dom plants) and part of that is environmental. Often providing them with less light than what they want makes them stretch to reach what light you have provided.

It could well be because of a lack of light and lack of leaves.

Light
The main characteristics of plants that aren't receiving enough light are that they tend to grow tall (check), the have significant internodal space (check), and the buds are not dense (check). It appears that the light is very close to the plants and that's good because AC Infinity lights do not put out very much light. I use AC Infinity products and am glad to see them in the marketplace but their lights are the weak point in their product line up.

Refer to the PPFD chart below (or on the AC Infinity site) and compare it to the PPFD map of a Vipar Spectra XS-1500 shown here (I use that as an example because it's good light and I'm using one right now for germination/seedlings).

Per the PPFD maps, even at a 12" hang height, the PPFD values for the Infinity collapse once you leave the 1' square area in the center of the light. It may be possible to run that light at 12" because the light saturation point for cannabis it 800 to 1000 µmols and, if the 998 number is correct, a plant could grow really well in the center of the light but at 390±µmols in the corners, there's not much light. Go to the PPFD charts for the XS-1500 and it's a completely different story. If we take out the 998µmols hot spot in the middle of the AC Infinity light, there is no reading in the 1' square in the center of the AC Infinity light that's as high as the lowest reading in the 1' square in the center of the XS-1500 or across most of the 2' x 2' light cast.

AC Infinity has some great looking products and it's clear that they've put a lot of effort into aesthetics and system integration but I don't understand why their lights, across the board, don't provide the light output of competing products.

Leaves
The plants in the picture have very few leaves below the canopy. Many growers remove leaves below the canopy because they're being blocked by leaves above them. The belief is that those leaves should be cut off because since they're not getting direct light, they're taking "energy" away from the rest of the plant. What that approach doesn't take into account is that any leaf that has a leaf between itself and the light source is functioning at a net photosynthetic loss. (This is easily determined by checking light levels in the foliage below the canopy - any leaf receiving less than 64µmols is a net photosynthetic loss.) Thus, if the grower were to enforce the rule of removing leaves that were blocked, the grower should remove, essentially, all leaves below the canopy. That won't end well.

What "cut off everything in the shade" ignores is that leaves have other functions besides photosynthesis. Most leaves in a plant are not net photosynthetic contributors but they do perform other functions that are vital to plant growth. Those leaves act as a nutrient store and they are vital for transpiration. When those leaves are removed in extremis, it reduces the possibility for the plant to grow to its maximum genetic potential.

You many not be keen on getting a new light, I can understand that, but, regardless, it would be a good idea to increase light levels (get a light meter and a factor of 0.015 to convert lux to PPFD) and cut back on the cutting back.

Just my tuppence.

pahpah-cee said:

try to bend them over. It’s too late to do much else. Next time you need to train them more or else they will outgrow your tent.

how tall the plant gets before flowering depends on the genetics. You cant compare your auto grow to another auto unless it’s the same exact breeder…even then their will still be slight variations.

photos are easier to control in a small/tight grow space. The YouTube growers (I assume, I don’t really go on YouTube) hype up autos like they’re easier to grow. They aren’t easier, and they’re less forgiving.

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Thank you for this insight, unfortunately the stems are too woody to train them any further. If I try to give them any more tension I’m afraid I’ll snap off the main cola. Next grow I will definitely try to train them more intensely and I will likely go with photos as well.

JASONsHAZE said:

Thank you for this insight, unfortunately the stems are too woody to train them any further. If I try to give them any more tension I’m afraid I’ll snap off the main cola. Next grow I will definitely try to train them more intensely and I will likely go with photos as well.

Click to expand...

Super crop them.

Delps8 said:

It could well be because of a lack of light and lack of leaves.

Light
The main characteristics of plants that aren't receiving enough light are that they tend to grow tall (check), the have significant internodal space (check), and the buds are not dense (check). It appears that the light is very close to the plants and that's good because AC Infinity lights do not put out very much light. I use AC Infinity products and am glad to see them in the marketplace but their lights are the weak point in their product line up.

Refer to the PPFD chart below (or on the AC Infinity site) and compare it to the PPFD map of a Vipar Spectra XS-1500 shown here (I use that as an example because it's good light and I'm using one right now for germination/seedlings).

Per the PPFD maps, even at a 12" hang height, the PPFD values for the Infinity collapse once you leave the 1' square area in the center of the light. It may be possible to run that light at 12" because the light saturation point for cannabis it 800 to 1000 µmols and, if the 998 number is correct, a plant could grow really well in the center of the light but at 390±µmols in the corners, there's not much light. Go to the PPFD charts for the XS-1500 and it's a completely different story. If we take out the 998µmols hot spot in the middle of the AC Infinity light, there is no reading in the 1' square in the center of the AC Infinity light that's as high as the lowest reading in the 1' square in the center of the XS-1500 or across most of the 2' x 2' light cast.

AC Infinity has some great looking products and it's clear that they've put a lot of effort into aesthetics and system integration but I don't understand why their lights, across the board, don't provide the light output of competing products.

Leaves
The plants in the picture have very few leaves below the canopy. Many growers remove leaves below the canopy because they're being blocked by leaves above them. The belief is that those leaves should be cut off because since they're not getting direct light, they're taking "energy" away from the rest of the plant. What that approach doesn't take into account is that any leaf that has a leaf between itself and the light source is functioning at a net photosynthetic loss. (This is easily determined by checking light levels in the foliage below the canopy - any leaf receiving less than 64µmols is a net photosynthetic loss.) Thus, if the grower were to enforce the rule of removing leaves that were blocked, the grower should remove, essentially, all leaves below the canopy. That won't end well.

What "cut off everything in the shade" ignores is that leaves have other functions besides photosynthesis. Most leaves in a plant are not net photosynthetic contributors but they do perform other functions that are vital to plant growth. Those leaves act as a nutrient store and they are vital for transpiration. When those leaves are removed in extremis, it reduces the possibility for the plant to grow to its maximum genetic potential.

You many not be keen on getting a new light, I can understand that, but, regardless, it would be a good idea to increase light levels (get a light meter and a factor of 0.015 to convert lux to PPFD) and cut back on the cutting back.

Just my tuppence.



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This was a really in-depth and much-needed response. Thank you for all is useful information about the lighting, I will consider looking into getting a new light for my next grow. I hadn’t taken into account how little light the AC infinity was putting out. I just turned them to the max and I’m hoping the helps the plants get what they need until I can find a long term solution.

JASONsHAZE said:

This was a really in-depth and much-needed response. Thank you for all is useful information about the lighting, I will consider looking into getting a new light for my next grow. I hadn’t taken into account how little light the AC infinity was putting out. I just turned them to the max and I’m hoping the helps the plants get what they need until I can find a long term solution.

Click to expand...

Jason (I assume that's your name) - thank you for taking my posting in the spirit in which it was intended (ATM, I'm writing a client of mine named "Jason", interestingly).

First off, for a first time grower, things are looking really good. Congrats on that. I've attached a graphic from one of the YouTube videos by Dr. Bruce Bugbee. I found it very helpful for me to develop an understanding of the "problem domain". I used it as a check list to dial in my grow environment. Based on what I'm seeing in your photos, you've dealt with a lot of the issues so you're off to a strong start*.

Re. leaves - my thinking is that it's better to leave too much on than it is to take too much off. Maybe that's a hold over from how I cook steak - you can always cook it more but you can't cook it less.

Light - I'm a big believer in "high light" and I admit I do stand on my soap box about it. It pains me to see endless discussion about the minutiae of nutrients while growers underfeed their plants by not giving them lotsa light.

If you're not familiar with PPFD, µmols, PAR, etc. check out Bugbee's video and, as much as I have strong reasons not to use the software, this site has a lot of good info on the basics of cannabis grow lighting. (My reason for not using Photone is based on having tested the application a couple of times and, second, the data that I'm gathering indicates that a $20± light meter is a better option for a lot of growers, but that's a lengthy discussion.)

Re. another light - there are tons of great choices. I bought the XS-1500 because it's a good light but, to be completely honest, the main reason I bought it was because it was available for next day delivery on Amazon. It's a good light and it has good numbers but there are quite a few other lights that, when it really comes down to it, are going to give you the same results. If you're giving your plant enough light, the brand of light makes, arguably, no difference. Per the steak analogy, they're all Choice grade New York strip steaks. Just don't overcook it and everything will turn out great!









*Note that I say that as an "old hand" with all of three grows under my belt.

JASONsHAZE said:

Thank you for this insight, unfortunately the stems are too woody to train them any further. If I try to give them any more tension I’m afraid I’ll snap off the main cola. Next grow I will definitely try to train them more intensely and I will likely go with photos as well.

Click to expand...

Look up supercropping.