DISCLAIMER: Everything taught and sold by BudTrainer® is to be used strictly for legal purposes. We condemn the production of illegal substances and it is your duty to ensure that you are complying with the law. The words "hemp", "cannabis", "weed", and "marijuana" are used interchangeably to refer to the same plant (legal hemp with less than 0.3% THC) for the purposes of this lesson.

Did you know that nearly 100% of commercial cannabis producers defoliate and prune their cannabis plants? They wouldn’t be doing it if it wasn’t increasing their yields. In fact, if left unpruned, your plant can attract mold and bugs such as spider mites, thrips, and aphids. But if you defoliate and prune it properly it will yield bigger buds, more trichomes, and an overall larger yield (with no pests). So let’s get to work.

When: week 5+ of the vegetative stage

Stage 1 of defoliation and pruning is meant to set up a strong canopy structure when your plant is young. By removing old and shaded leaves, and removing small branches, your plant transfers its energy toward the stronger branches and leaves left behind, thus promoting a much stronger base for your plant.

Growing Outdoors?

Stage 1 can be repeated every 2 weeks when growing outdoors.

Growing Autoflowers?

Skip Stage 1 if you are growing autoflowers, as they only get 4 to 5  weeks of vegetative stage time.

When: 3 to 4 weeks after switching to flower

Stage 2 of the defoliation and pruning process is the most essential stage. Performed after the flowering stretch phase, stage 2 is where you get to “clean up” the small and shaded leaves, but also all small bud sites that would otherwise form larfy, popcorn bud. You will leave behind only bud sites that can form big buds.

Growing Outdoors?

The process is exactly the same, but since you can’t know exactly when marijuana plants switch to flower, wait to defoliate until your plant has stopped stretching, and started forming bud crowns.

Growing Autoflowers?

Instead of performing Stage 2 in one day, prune and defoliate on a daily basis, only removing 3 to 5 leaves or branches in order to avoid stress.

When: 1 week prior to harvest day, or on harvest day itself

Performed one week before harvesting or on harvest day, Stage 3 is where you remove all fan leaves that don’t have trichome heads attached to them. This not only makes it easier to trim your buds later on, but it also helps expose the lower buds to more light for that last week of flowering, thus helping them reach the same maturity as the top ones.

Whether you are growing autoflowers or outdoors, Stage 3 is always the same.

Fan leaves - these are the larger leaves that come out directly from the branches. Fan leaves are the symbol of cannabis (although we hardly use them) and their main function is to collect light and CO2, store nutrients, and transpire. Fan leaves have no use after harvest, since they hardly have trichomes attached to them.

Sugar leaves - these are small leaves that stick out of the buds and are covered in trichomes (hence the name). They are much smaller, and their main function is to store nutrients for the flowers and grow trichomes to attract pollen. For this reason, sugar leaves contain a lot of THC and CBD, and should always be harnessed for procoessing (like making hash or edibles).

Our sun is nearly 100 million miles away, which means that it doesn’t matter if your plant is a few ft taller or shorter - the bottom and the top leaves will feel no difference in light intensity (as long as they are not in the shade). However, when it comes to indoor lighting, the intensity of your grow light decreases a lot as you get farther away from the source - from 5 to 10 times weaker every foot of distance away.

Airflow is essential for plants to absorb CO2 as it helps circulate the air released by the leaves (which is full of oxygen) and renew it by air that is full of CO2. For this reason, it is equally important to train indoor and outdoor marijuana plants to maximize airflow around the leaves and inside of the canopy.

The main difference, however, is that outdoors plants have the extra pressure from pests while indoor plants generally don’t. This is why we highly recommend defoliating outdoor plants at least once a month to clear out all old leaves that are turning yellow, not catching any more light, or that are blocking airflow to the middle of the plant. As long as you don’t create pockets of clustered leaves, you should be safe from the pressure of pests!

Microclimates are little pockets of air in different parts of your growing space that are different from the overall climate you set. For example, you can set a temperature of 26C/79F and RH55% in your fancy exhaust fan, but if you measure the middle of your canopy you will end up with a cooler temperature and higher RH.

Microclimates are most common on the corners of your growing space, the underside of your canopy, and in the middle of the canopy where it’s humid. Since these areas are usually more shaded and have less airflow, they make the perfect environment for pests to thrive in and the worst environment for photosynthesis to happen - due to what is called photorespiration, which is the opposite of photosynthesis.

Plants don’t just absorb CO2 during photosynthesis, they also absorb oxygen “by mistake” in a process called photorespiration - where instead of producing sugars, they consume sugars - becoming smaller instead of bigger. This is the reason why the leaves inside your canopy are smaller - because there is too little CO2, which means the leaves are “respiring” more than “transpiring”, i.e. consuming more than producing.

To summarize: shade + stale air = less CO2 + less light = more photorespiration + less photosynthesis = smaller plants/leaves/bud sites + more pests

It is very common for new growers to fear defoliating and pruning their cannabis plants. After all, you are hurting them by cutting it up. But if you start slow and follow the rules you just learned, you will always have great results!