Growing Big in Oregon


Is Bigger Better?

Does the overall quality and potency of the flower decrease as the size and yield of the plant increases? In other words, do small plants produce better buds? Apparently, there’s an old wives’ tale insisting this is the case, but my own stance has always been that larger plants are superior simply because that’s how they grow naturally. But it’s tough to confirm this indoors, so I’ve been on the lookout for a proper greenhouse with which to prove my point. I wanted to conclusively answer two questions: How large can a potted cannabis plant become, and does potency increase or decrease with plant size and yield?

In Oregon, a medical marijuana patient can grow up to six plants—but there’s no restriction on just how large they can be. So, last spring, using only one medical marijuana card, I decided to grow six plants as huge as I possibly could in a 28' x 48' greenhouse located in the high desert of Central Oregon. For this project, I chose four of my most potent strains: the Tahoe OG from Cali Connection, the White Russian from Serious Seeds, Jack the Ripper from TGA Seeds and my clone-only Headband cut. They’d already been growing indoors for about six weeks and were in 15-gallon pots at the time they were brought to the greenhouse.

On the Grid

In order to support the weight of what I hoped would be massive plants, I had to first construct multiple tiers of “screen of green” (ScrOG) netting. I used bamboo stakes and zip ties to construct an overhead grid system strong enough to do the job without damaging the frame of the greenhouse. This turned out to be the most important step, without which the plants would have been completely unmanageable—by the end, they would have simply toppled over without added support from the ScrOG.

For newcomers, “screen of green” is a growing technique that uses netting to spread out the canopy of the plants and then provides support to their branches once they’ve started packing on bud weight. When a plant feels the stress of a branch in danger of breaking, it will slow down that branch’s bud production as a matter of self-preservation. If the branch is given extra support, the plant is free to continue loading it with buds until the grow cycle is finished, provided that all other conditions are favorable.

After my netting was up, the already large plants had to be transplanted from their 15-gallon pots into 150-gallon Smart Pots. The position and spacing of the plants was a huge consideration at this point, because once they were transplanted into those giant pots, there was no way we’d be able to move or reposition them again. We had to give them plenty of room to grow, but also reserve enough space to easily maneuver around them. Each plant was allotted a 12' x 12' space, which by the end allowed just enough room to move around on ladders between them.

Each branch is trained into its own square of screen.

Transplant Time

Getting the heavy soil and root mass out of one pot and into the other without it falling apart was a nerve-racking experience, to say the least. You just have to hope that the stalk is strong enough and the roots healthy enough to hold all the soil together. Too much moisture and it’ll be too heavy; yet the drier the soil is, the more likely it is to crumble apart. Transplanting your plants is a delicate procedure that requires precise timing. Once the process was complete, large bamboo stakes were used to secure the plants in place while we waited for them to reach the first layer of ScrOG netting.

The following month was pretty slow going, as the plants were acclimating to their new surroundings and their roots were spreading through the giant 150-gallon pots. Then, around the Fourth of July, they suddenly began to explode in size. Each plant’s branches would grow up to 3 or 4 inches in a single day. This marked the beginning of a very intense training and pruning regimen.

Training Day

The cannabis plant is very sensitive to its surroundings and will send extra growth hormones to the highest branches in its canopy. It does this because the most elevated branches have the best chance of catching pollen, thus fulfilling the goal of the plant’s reproductive cycle. This explains the Christmas-tree look of most untrained plants, where there is one large bud at the top and several smaller buds of decreasing size below it. If you train all of the branches in the canopy to be level with one another, the plant won’t choose any favorites and the buds will grow larger and more uniformly.

As the plants got taller, the netting was used to spread out their branches and distribute them evenly, each to its own space. The openings in my ScrOG netting were 6" x 6" squares; in a 12' x 12' area, there are 576 of these spaces. My goal was to fill each one with its own branch, which would ultimately become a massive cola. We achieved that result and then some. I wanted to show that the ScrOG technique is equally beneficial outdoors and that growing your plants like this can make it much easier to control issues like mold, powdery mildew and pests without compromising yields.

Despite all the training and bending, the plants continued growing for about eight weeks, until they were somewhere from 14 to 15 feet tall. The three layers of ScrOG netting that we’d installed previously weren’t enough to contain them; we had to add a fourth layer while we still had the chance, in anticipation of the giant buds to come. All of the growth below the first layer of netting was removed, and all of the smaller underside branches that didn’t receive light were taken off as well. We also pruned the plants until all that remained were about 600 soon-to-be colas of varying sizes, depending on the strain.

Airflow through the undergrowth prevents mold.

Water World

I decided to hand-water the plants, as opposed to using a drip-feed system, because it gives you more up-close and personal time with them and can help you better understand their feeding habits, ultimately keeping them happier. When growing outdoors, one of the biggest challenges is keeping plants healthy the entire season, especially if they’re in pots and not in the ground. At harvest time, these plants were nearly eight months old, and the only way to keep them healthy that long is to keep both the soil and their roots happy. But the more you automate the feeding process, the less attention is paid to the soil.

The plants also had different needs and were fed accordingly to achieve maximum potential. Organic nutrients were added twice a week, as well as a generous scoop of beneficial mycorrhizal fungi to keep the roots happy. Watering by hand turned out to be a lot of work, but I think it was worth it.        

Once the buds started forming, the only things left to do were to water and inspect the plants daily for bugs and powdery mildew. Store-bought nutrients are not formulated or tested for plants this size, so once a week we foliar-fed them with a medium-strength seaweed-extract solution to supplement all the nutrients they were using to achieve such rapid growth. This kept the plants nice and green up until the last three weeks, when we began the flush.

Flushed Out

I figured that plants this size could use an extra-long flush, since they’d been building up nutrients for the last six months. We ran 100 gallons of pH-adjusted (5.8) water through each pot every other day for the first week and then continued to feed them straight water for the remainder. Over the last few weeks, the buds grew noticeably larger and frostier every day. Finally, a week before Halloween, the plants were ready to begin harvest.

From above, no screen is visible due to the heavy colas.

Reaping the Results

The first to be harvested was the White Russian. It boasted some of the biggest buds in the entire greenhouse: Most were the size of my forearm, while the lower ones looked like pinecones. The scent was a sweet, woody citrus with a clean lemon undertone. However, buds that big can actually be dangerous to the plant, since they’re so much more susceptible to bud rot. We got really lucky, as we lost only about an ounce to the dreaded botrytis. This is one case where a dry climate can be advantageous.

Next to come down were the three Tahoe OGs. They definitely had the frostiest buds in the room—not huge ones like the White Russian, since most were the size of golf balls, but they were densely packed and there seemed to be a million of them. (Luckily, it’s an easy strain to trim or we would’ve been at it for weeks.) I prefer the Tahoe to many of the other OG varieties because it has a much milder scent and flavor that to me is just so much more satisfying. This was the bud I was most excited to smoke.      

The Headband was next up. When we brought the plants outside, this was the smallest one, but it didn’t take long to catch up to the others, and by harvest time it was actually the largest. The buds were very impressive: They grew like giant spears about the width of a soda can. Headband is one of those strains you either love or hate, as it reeks of dead fish, road kill and petrol—one of those smells that, if you encountered it in nature, you would never consider a good thing. I happen to love it, but apparently the neighbors didn’t. Also, the cold nights in late October caused the leaves to take on deep purple and pink hues. It was something I’d never experienced with the Headband grown indoors, so I was really excited.

The last plant to come down was Jack the Ripper. The odor on this one was nearly overpowering: The slightest agitation of the plant would fill the entire greenhouse with the smell of sweet, limey shoe polish. The JTR was always the slowest grower and the last to start budding, although once the budding did begin, it nearly caught up with the rest. At just over six pounds, it turned out to be the smallest-yielding plant. But Jack the Ripper has never been known for heavy yields; its flavor and medicinal quality are what make it so desirable.

Let It Dry

Drying such an enormous amount of bud—as well as figuring out how to process the trim in a secure way—took some planning. I rented a big moving truck for a couple of weeks and hung up some eight-tier mesh drying racks with a dehumidifier. Then I decided to set up my closed-loop extractor and vacuum oven in there as well. This allowed me to process the trim onsite while I waited for the buds to finish being trimmed and dried.

By the time everything was wrapped up, it was clear that the project had been a huge success. My question about whether or not this training method would yield well has certainly been answered. The White Russian, Headband and three Tahoe OGs were nearly identical in yield, at around eight pounds per plant (not counting the small lower buds that were reserved for making oil). These numbers could be increased dramatically with the right strains: As I mentioned earlier, I chose my most potent strains, not my best-yielding ones.

Lab Testing

I was very pleased with the finished product: The bud’s overall quality and appearance were indistinguishable from some of my finest indoor. All that was left was to turn some samples over to the lab for analysis.

All of the samples passed inspection for mold, mildew and pesticides, which I attribute largely to the style in which I trained and pruned the plants. Many of the farmers who grow their plants in the conventional round, bushy style are often plagued with powdery mildew and bud rot due to the poor ventilation created by all that thick foliage. It’s definitely better to redirect those side branches up to the canopy, where they’ll be level with the rest.

We also had the samples tested for potency, and the results were conclusive: Each sample came back consistent with the best results from the same strain grown indoors. And one sample really stood out: The THC content of the Tahoe OG came back at a staggering 28.9% THC. This, combined with the other results, absolutely proves to me that a plant’s potency isn’t affected by its size. I encourage everyone to grow your plants as large as you possibly can, because in this case, bigger is indeed better!

Each plant grows into a massive bush when roots are given room to spread out.

Photos c/o Dru West

  1. I appreciated the article very much. Especially some of the details about space requirements. So when you say the plants yield about 8 pounds, at what point did you weigh the product? After drying and manicuring? How about curing (and after how long)?

  2. So I want to do this but add some indoor veg time and add HID lights. How much more canopy do you think i will need?

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