By Luke Sumpter

If somebody told you to chop off the vast majority, or all, of your cannabis plant’s leaves in order to massively enhance yield, would you listen to them? Or would you merely disregard the claim as the suggestions of a mad man?


Well, the person in question might actually have a valid point. Something about severing off the fan leaves of your indoor crop during the flowering phase seems to rapidly ramp up the size and vigour of cannabis buds.

Defoliation is the term usually assigned to the practice of clipping off a few leaves, but a new term has been developed for fully stripping a plant of its leaves, named “schwazzing”.

The term schwazzing was born out of a book named Three a Light, penned by author Joshua Haupt. The very concept of the book is the application of various growing methods in order to produce a mammoth 3 pounds (~1.4kg) of weed under a single grow light. Schwazzing is a training method featured within the book that's said to help growers achieve such barbaric yields.

Haupt compares schwazzing as kind of like going to the gym. In the gym, a muscle is beaten up and exposed to stress. Muscle fibres are torn and damaged, only to grow back stronger during the anabolic phase.

Weed plants respond in a similar way after such tough love. However, Haupt makes a point that after the gym, muscles will only respond well when fed adequately. This metaphor translates into the notion that plants must be given appropriate nutrients after the removal of their prized and precious leaves.

In the absence of pretty much all of its leaves, it may be the case that all of the plant’s energy, now spare, is distributed to the buds instead. This may explain the explosive growth of the buds when plants are subject to such methods.

Schwazzing Cannabis


Schwazzing typically takes place twice within the grow cycle of a crop. The first bout occurs just before the flowering phase is initiated. The grower will remove the vast majority of fan leaves from plants, leaving them looking almost bare.

Although this might appear shocking and damaging, it is said to pay off further down the line. The photoperiod should then be changed to a 12 hours on, 12 hours off cycle in order to induce the flowering phase of the grow cycle.

The removal of such large amounts of leaves will expose bud sites to light that previously would have been obstructed by the canopy.

Schwazzing Cannabis


Schwazzing then takes place for a second time 20 days after the initiation of bloom, roughly ⅓ of the way through the flowering phase. During this time, new fan leaves will have grown back, and in doing so, will have started to once again form an obstructive canopy, preventing large amounts of light from directly stimulating the buds.

Many buds will be starting to form at this point, so it is a good time to start to trim away those fan leaves and expose the flowers to some strong light. After this point in the grow cycle, plants won’t be making many more leaves at all, so it’s important not to completely strip plants bare. Instead, let some leaves remain in order to fulfil their biological purpose, focussing mainly on removing large fan leaves that block a lot of light.

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