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- #721
Newbie Grower, Carmen Auto x Diva, Outdoors
- Thread starter CBDMed
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I don't grow autos but hear they are a bit finicky as any setback materially impacts the final haul. There is no grace period with them so that small one may have gotten stunted earlier due to a watering issue or a reaction to nutes or wind or who knows what and now will lag the others.
cbdhemp808
Well-Known Member
My 40g pots are 18" tall and 25.8" dia.
cbdhemp808
Well-Known Member
I still think Ed is correct that cannabis roots need a lot of lateral spread, and the extent of this determines the width of the canopy. (Again, for small pots, this whole conversation is different.)
Thanks for the clarification about the clone developing a working tap root... reminds me of a bee hive producing an emergency queen.
Let's consider my DIY 15g cylindrical fabric pots, for example. I want to give as much lateral root spread as I can in that pot, and some good depth, but favoring lateral spread. The pot dimensions are 15" tall by 17.2" wide. Note that this is almost "square" (i.e 15 x 15), but the 2.2" more width than height translates into 3.5 more gallons of soil for lateral spread, as well as downward spread.
What if the pot dimensions were reversed... 17.2 tall and 15 wide? You maybe wouldn't guess it, but the pot is now a 13.16 gal pot, instead of a 15 gal pot. We've lost almost 2 gallons of soil for both lateral and downward spread. What size pot would we need to turn this height/width ratio into a 15 gal pot? The answer is: 17.83 tall x 15.73 wide... i.e. 0.63" taller and 0.73" wider.
I feel like my 15 x 17.2 dimensions are a good balance, and the pot is nicely portable... 2 people can easily lift it into a wheelbarrow.
cbdhemp808
Well-Known Member
Yes, but I think the practice of providing more width than height, for large pots, didn't originate with Ed. I think it's quite common. We are talking about growing in soil, in large pots. Let's say maybe 15g or more.
As Emilya schooled us, clones do develop a working tap root, but I'm going to guess it's not the same as a seedling's tap root. So, perhaps it is more important to provide more depth for a seedling than for a clone. I don't know.
cbdhemp808
Well-Known Member
Ed's book is not seed- or clone-centric – he covers both.
The "flatter" container isn't an Ed idea... I think it is a common practice for large pots.
cbdhemp808
Well-Known Member
I'd like to say one more thing about this whole pot dimension discussion, for large pots, and that is... there is some economical consideration involved. The way I see it, if space wasn't a concern, and cost of organic living soil (w/ nutrients added) wasn't a concern, and weight of full container wasn't a concern, then we could add vertical space to our heart's content. But all of those things are usually a concern. So, it makes sense to me to opt for lateral root spread over root depth. One can arrive at a happy medium.
I found this interesting experiment that compared root growth of seedlings to clones, side by side: Root Comparison: Seedlings vs Clones - Superior Hemp Clones
Takeaway (from this one study): clones produce more roots, finer roots, and more root mass.
Lastly, if one looks at the root system of cannabis planted in the ground, let's say from seed, it looks like the ratio of width in the upper soil layer (let's say first 20") to the depth of the system is about 2:1. If this is actually true, then it makes sense to mimic this ratio, to a degree, for a container. Apparently, the root system resembles an inverted pyramid, and maybe about 50% of the biomass (more?) of the system is in the upper soil layer... something like that.
Sorry to not be more definitive, but it's hard to find good, recent data for all this.
I found this interesting experiment that compared root growth of seedlings to clones, side by side: Root Comparison: Seedlings vs Clones - Superior Hemp Clones
Takeaway (from this one study): clones produce more roots, finer roots, and more root mass.
Lastly, if one looks at the root system of cannabis planted in the ground, let's say from seed, it looks like the ratio of width in the upper soil layer (let's say first 20") to the depth of the system is about 2:1. If this is actually true, then it makes sense to mimic this ratio, to a degree, for a container. Apparently, the root system resembles an inverted pyramid, and maybe about 50% of the biomass (more?) of the system is in the upper soil layer... something like that.
Sorry to not be more definitive, but it's hard to find good, recent data for all this.
And wider vs taller makes for a more stable base especially as the plant grows taller and more top heavy.
Thanks for sharing this. Interesting.
The results are also consistent with my recently harvested clone in a sub irrigated container. It was my first test of this process and I used an off-the-shelf container with a comparatively small reservoir. When all the soil was washed from the root ball it was a mass of very thin fibrous root hairs, with no tap root in sight, no circling of roots around the inside of the pot, etc.
Emilya Green
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A lot of people don't work on their lateral root development much, so a wider container isn't going to help them. The importance of the top set of spreader roots should not be underestimated though, and because of the ability to rapidly feed through those top roots, and even to be able to water a bit each day by using them, it is easy to see why Ed and others preferred the wider containers.
I am taking advantage of both worlds with my present final 5 gallon containers. They are not only taller than wider, catering to the needs of the lower feeder roots, but they are also tapered so that there is more surface area at the top than at the bottom, so as to also concentrate on the more spread out needs of the upper spreader root system.
I am taking advantage of both worlds with my present final 5 gallon containers. They are not only taller than wider, catering to the needs of the lower feeder roots, but they are also tapered so that there is more surface area at the top than at the bottom, so as to also concentrate on the more spread out needs of the upper spreader root system.
cbdhemp808
Well-Known Member
OK, so you are talking about small containers (5g) and I am talking about large containers (15g+). Are you also talking more about indoor grow than outdoor?
Emilya Green
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I am talking mostly about people who start in their final containers, indoor or outdoor
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- #733
CBDMed
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- #734
CBDMed
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@cbdhemp808 , thanks for the pot measurements!\
I think I understand what you are saying about lateral spread in that they say a tree's root systems generally tend to mirror their canopy (so the roots get almost as wide as the canopy outdoors in soil).
However that said, I have seen plenty of cannabis plants growing in pots with a canopy much wider than the pot!
So I do not know that I could agree that the ability of the roots to spread laterally will limit canopy growth.
I can understand the importance of portability for your constant-harvest setup, and the setup you have seems to make perfect sense.
However, just to comment, since I am growing in batches, there should not be a need to move the pots.
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- #735
CBDMed
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Yes, the smaller pots online are mostly tall, whereas the really big pots (30G+) are mostly wide.
But I wonder if that is because that is what is best for the plant, or if a lateral pot seems more desirable because it looks more stable.
Emilya Green
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it is because vertical height is usually the limiting factor in an indoor grow
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- #737
CBDMed
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Yes, I was looking for some good studies of side-by-side grows between a tall container versus a wide one, and could not find anything.
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- #738
CBDMed
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Sí. The wider base does seem more intuitive and appealing.
And I can see that lateral stability would seem important if growing outdoors (with wind).
Only, I am planning to grow in a closed greenhouse (no wind). So is lateral stability a huge concern?
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- #739
Emilya Green
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I roll my containers around on wheeled carts, and even though my tall 5 gallon containers are less stable than a squat grow bag would be, I haven't spilled one yet. I also have zero concern that my wall fan will ever be able to topple one of these.