I don't have firsthand knowledge of how to do this, but I did get to ask a similar question of someone(s) I'm fairly certain had the same thought decades before I did, and possibly before I was born. This is a paraphrasing of what was explained to me when I, in a scissor-hash induced haze, asked how to grow the most ridiculously huge individual plant possible to try to take advantage of plant-count laws. ~
If you start a plant in the fall, inside of a big PVC pipe in a greenhouse with additional lighting, it will stretch towards the light, without growing out at all. Once you get it to be 6-8' tall, you surgically split the stem, from the roots up, but not all the way. Coat every newly exposed surface with rooting hormone, splay that stem out, and bury it in a giant container, like a home-made hot-tub sized thing, all on a huge pallet. Then nurse it back to health without the PVC tube. Once you get it back up to 6-8' tall, you do the same stem-split, but from the top down. This time, after dousing everything with rooting hormone, wrap up all the exposed areas with grafting tape. Keep nursing it back to health until it can be moved outside into the sun. Make sure your forklift is suited to move the monster outside. At some point, you need to build a big trellis system, IIRC. I was shown some pics of plants that seemed to be a solid 20' tall, and round, like a ball. It was certainly the biggest plant I have seen a picture of. I can't recall what he said they pulled from it at the end of the year, but I remember some others with decades of outdoor growing experience estimating 50 to maybe 75% for the claimed yield. I'll see if I can dig up the pics they shared.... This first pic is what the split stems grow out like, but this is a "smaller" plant. Second one is after it's been outside a bit. Not a 30# monster, but it shows what's somewhat reasonably possible.
Last edited by beefalo bill; 07-12-2018 at 05:59 AM..