Is there an Optimal Final Height for the plant?
Most everything I read says to continue the Vegatative stage until the plant is about 1/2 its desired height, then flip to Flowering stage.
Assuming you are keeping the canopy as flat as possible. Should you try for as tall as your tent/light will allow without burn? or is there an optimal height found to give best yield/quality? Does the plant waste energy moving the nutrients up a taller plant?
I see amazing pictures here of bountiful plants that appear to be under 36", with lots of fat dense colas.
Thanks.
That's an interesting question! I'm definitely not an expert in this and I'd love to see other opinions, but this is what seems to be true for me when growing indoors.
When it comes to training, in the best case scenario you want to get long colas that are as long as your light penetration. However, there's no point in having buds that are located below where they get light, because they will not fatten up. So indoors the optimal length of buds is dependent on your grow light.
Let's say I have a 250W HPS grow light. The longest cola I was ever able to get from that light was about 12" long. There never seems to be significant buds below the 12" mark with the 250W. So I want about 12" of "stretch" on those colas after the switch to 12/12. So I personally feel like switching the plant to 12/12 when it's about 12" tall ends up giving you colas that are 12" long. However, if I let the plant grow to 2 feet first, I'd end up with 2 feet worth of colas being added to the plant, but they would only fatten up down to about 12", and all that lower growth that was made in the vegetative stage would have been wasted time.
Under a 600W HPS, I haven't ever seen a cola really thicken for longer than 2 feet even if light is getting down almost to the floor. So I'm not sure how much benefit you would get by switching to 12/12 after the plant is 2 feet tall. These plants were switched at around 20".
You can support even taller plants and longer colas under a 1000W light.
These restrictions don't seem to apply as much to outdoor plants. It seems like outdoors, plants will keep getting taller and taller as long as they have enough direct sunlight and root space. Root space seems more important outside and with soil than indoors or with coco or hydro. Root space is usually provided with humungous fabric pots (600+ gallon containers) or with raised beds full of good soil. You'll see this results with colas sticking out everywhere! For example this plant got 12 feet tall in just one summer, with a 3+ foot cola at the top!
But that's very simplified, and it's a lot more complicated than just that in practice. The strain makes a huge difference, as some plants react to light differently, and may be able to support different sized colas.
But in addition to the height, the overall size/mass of the plant has a big effect on your final yields. A bigger plant can simply support more and bigger colas. Because of that, it's good to build up overall size as opposed to just height, if you want to maximize yields. And many growers let their plants get bigger horizontally, while restricting their ability to grow taller than the light can support.
Also, if you grow a very short plant with tons of colas and some defoliation, the plant will often respond by growing basically just a bush of buds, even though each individual bud isn't that long. However, if you can get a bigger plant with that same density of buds, you'll end up with bigger yields overall, just because there's more places for buds to grow.
What do other growers think?