OK, Gary, I’m going to chime in my two cents here: I will, however, preface my response with a brief disclaimer: defoliation is as personal as choosing your underwear in the morning; meaning it’s all about what works for you!
I have a technique I have been developing over the course of a lifetime of growing. The technique calls for a “rule of five” approach to pruning, which demands a FIM (Fuck! I Missed! [i.e. removing about 75% of the new growth at the top of a node, leaving about 25% of the node}) every five new internodes. By doing this FIM, the grower is transforming the energy within the plant system via a series of hormonal responses. By doing this I achieve two desirable results: one, I have literally hundreds of blooming buds; and two, I have an extremely even canopy with every flower top receiving equal light. Another ancillary benefit to this pruning practice is virtually every flower on the plant has “bag appeal” (thereby minimizing loss through waste) and all the buds test at similar cannabinoid/terpene levels (high standard of purity).
When I approach the topic of the removal of leaves, I have a balanced approach: I always try to never remove too much. I do, however, remove many leaves during the course of the plants growth cycle, but only during very specific times. I always remove the leaves that are demonstrating pronounced chlorosis (yellowing). Keep in mind leaf shedding happens naturally during the plants’ life cycle. I do the majority of my leaf removal during the first two weeks of flower, which is when I really shape the canopy, allowing for that even flower set I am looking for. After about the second week of flower, I pretty much leave the FIM/pruning alone until the flush phase.
When the flush begins, a healthy plant will begin to consume remaining micro and macronutrients still remaining in the canopy. As the remaining nutrients are spent, you will notice an increase in yellowing in your leaves. This is a good sign. Your finished product will be cleaner for this. I remove those yellow leaves which the plant has already begun to shed.
My pruning techniques work for me. I routinely pull over one gram of harvested dry product for every watt of light consumed. I largely attribute my success as a grower to learning to respond to the needs of my plants. Pruning and trimming are huge parts of a plant’s needs.
Like people, plants can be picky. Different cultivars respond differently to pruning and defoliation. I find that sativa-dominant strains tend to enjoy a good “haircut” more often that stout, short, indica-dominant varietals. Your plant will let you know what and how much to trim. You just have to tune in to her needs.
