Super cropping: how “pruning” (training) can help you produce bigger, better buds.
So the question we all want answered is “how do I get the biggest buds from my cannabis plants?”
Providing the optimum environment, the right lighting, the best nutrients etc all comes into it, but advanced level growers use sophisticated techniques to push bud production even further. Pruning your plants not only alters their shape, but also their hormone (axuin) distribution. (see our overview of cannabis pruning techniques here). Super cropping (or as we joke, “high stress training”) manipulates the plant physiology to maximize bud production from a cellular level. Its a combination of multiple pruning techniques.
Brief botany lesson: understanding why super cropping works:
At its most basic, pruning is used by gardeners to keep long living plants healthy and at low risk of disease. More advanced techniques are also used to shape and train plants. Understanding the principles of how and why plants respond to pruning is the key to realizing their potential and ever resourceful marijuana growers have adapted some of these useages to get better harvests.
So lets have a quick botany lesson. (if you want, skip this bit and go down to “How to supercrop”!)
1: APICAL or terminal bud (growing point)
2: LEADING SHOOT
3: AXILLARY BUDS form in leaf axis
4: LEAF STALK
5: LATERAL SHOOT develops from a lateral or axillary bud. It will have its own apical bud.
6: a NODE is a point from which leaves and stems develop. The stem between nodes is called an INTERNODE.
Understanding apical dominance
The most active site of cellular activity in plants is at the green shoot tips at the top, where the hormones that stimulate and control the plant’s growth are made.
The most growth is made just below the apical bud, in the leading shoot. This is because the top bud imposes what is called apical dominance, whereby the hormones move down the stem and inhibit the growth of the side buds (the lateral buds). These lateral buds will only grow into side branches once the growing tip has grown away strongly. Meristem tip pruning exploits apical dominance. When you prune the growing tip, apical dominance moves down the plant: shoots then sprout from buds immediately below the wound and from lower down on the stem. The topmost remaining stem will grow most strongly, but because it does not have absolute dominance, shoots will also grow from the axillary buds lower down the stem.
Because apical dominance is strongly associated with vertical growth, it can also be broken by pulling a vertical shoot down to almost 90º and tying it in horizontally. LST is – by its name, a low stress training technique that exploits this.
When you force a lateral shoot into a horizontal position, you break the dominance of the lateral apical bud. A number of side shoots then develop simultaneously from buds along the stem, all will grow upwards with similar vigour and flower (this technique is used for cordon fruit trees to increase crop yield from the one tree, or climbing roses to encourage flowering).
Knuckling pushes the marijuana plant a little harder than LST does. I’d hate to call it EXTREME STRESS TRAINING because we never want to put our cannabis plants in danger … but in some ways the name is apt. LSTing depends on gently encouraging the lateral stems on the plant to grow out horizontally through tying in or weighing down. With knuckling you don’t encourage, you DEMAND the plant … and here’s a little more botany to explain why.
The second area of intense cellular activity is in the CAMBIUM layer.
1: Tough outer skin (the “herd”) which protects the soft tissue within, and minimizes water loss.
2: In the cambium layer, cells divide and diversify to create vascular bundles of transporting tissues and increase stem girth.
3: Vascular bundles of cells carrying water and mineral salts (xylem) or manufactured food
(the phloem) from the leaves to all parts of the plant.
4: The pith is a connecting matrix for other tissues.
Crimping & Knuckling
both exploit the high level of activity in the cambian layer. Stressing the stem within the cambian layer (without breaking the outer “herd” puts the cells into hyperdrive as they work to repair the perceived damage. Not only do they repair the damage, they strengthen and improve it, with the xylem and phloem cells bigger than before. Thus the stem receives more food and water more quickly. If you think of these vascular cells as a road infrastructure, they’ve just been upgraded from a country lane to a 3 lane motorway.
Gentle but firm is the key to this one. Starting from seedling stage, gently twist the stem in opposite directions. Continue up the branch every 5cm or so and repeat once a week. Remember the aim is to simulate extreme flexing for the plant, not put pressure on the root system or damage the outer protective layer.
One issue with crimping is that if you have a lot of plants which you’ve topped (meristem tip pruning) to create multiple stems, this is going to be very time consuming … you can simulate the same effect to a lesser extent by making sure you have a fan aimed at the plants stems. This is what creates stronger cambian tissue in nature (well wind, rather than a fan!)
So what is supercopping? And how do you do it?
Combine stressing at cellular level with breaking the vertical apical dominance through horizontal training and the end result is, quite simply, more marijuana bud.
Supercropping is simply combining methods of training. Its not a case of supercropping vs topping, both techniques can be combined. Pick the techniques which seem best to you …
OK so that’s the theory, how does it work in practice? Here’s what we’ve done for super-cropping.
- We broke absolute apical dominance by topping the plants after around 2-3 weeks of vegetative growth. This encouraged 3 main stems to develop instead of one.
- Knuckling. (if anyone knows a better name for this I’d be grateful!)
If LST uses weights or ties and SCROGing involves a screen and weaving plants, knuckling uses the repair abilities of the cambian layer to make the plant make its own support structure. All work on the principle of breaking vertical growth dominance. (and if you skipped the botany lesson above, you’ll have to go back and read it if you want to know why)
But you have to be brave to create knuckling. With one hand support the lower stem. With the other, bend the stem into a right angle until you feel the inner core snap. (Yes you read that right). Try not to tear the outer protective layer (this will take longer to heal) but if you do, splint with cloth or even gaffer tape.
When to start super cropping?
We did this 5 weeks into vegetative growth. This photo taken a few weeks later shows the formed knuckle and increased stem width after the bend.
These white widows have been grown in pots, in a coco-perlite mix. Move ability is key for watering, and I knew they would need to be transported before end of flowering so couldn’t tie or scrog them. Knuckling has induced horizontal training without any external support structure:
The 3 thick stems now spread horizontally and there are innumerate sideshoots growing vertically. When put into flower, each of these side shoots will form their own colas.
Now we’ve exaggerated this whole process for the purpose of writing this article. The white widows have been left in vegetative growth for a long 14 weeks, which you wouldn’t normally do with an indoor marijuana plant. It does show you however how its possible to get one hundred heads on an outdoor cannabis crop – and keep the plant neat, tidy & just a little less noticeable ….
The technique we’ve described doesn’t need such a long veg stage nor such big marijuana plants though … it will even work on autoflowering cannabis, which has virtually no vegetative stage at all. What we have noticed though is that the process needs to be done before flowers start. Super cropping during flowering means stress that will delay flowering whilst the plant attends to damage done by the techniques. But I guess that goes without saying really.
What we need now is a photo of the finished plant once its flowered … hang tight for an update, or follow Heavy Ds grow!
Here we go, a super stinky auto thats been knuckled heavily to reduce its height. This pure sativa based auto grows BIG BIG BIG and isnt normally recommended for an indoor grow. However its been grown under a Fero LED Adjustable indoors and its turned out great!
This plant is a monster! It takes up a 1.5m by 1.2m square area and stands at 80cm. It has its own self-supporting scrog effect thanks to the knuckling, and has survived moving house in the back of a van fine!