There are a surprising number of ways to trim your marijuana, and each technique has a specific purpose. When marijuana growers talk about trimming, they might be referring to either pruning or clearing harvested branches of leaf material to expose the cannabis buds.
Trimming isn’t a one and done task though: it’s important to trim weed throughout its growing process to achieve the best quality growth and highest yield when it’s time to harvest.
Keep in mind that pruning plants and trimming buds contribute to a good harvest in different ways. We’ll review all of the marijuana trimming techniques you need to know in depth in this article, when to use them, and how they affect plant growth.
why trim a marijuana plant while it’s growing?
Trimming marijuana seems counterintuitive at first. Why waste any part of your harvest? The answer is that when left to grow un-trimmed, marijuana plants will only grow a few buds. As marijuana plants grow, they shoot up and fill themselves in with lots of leaves. The plant will grow like a Christmas tree if left untrimmed with a thick wide base and a tapered top, crowned with a single large cola of flower buds at the very top, and some small flower buds along the sides. This isn’t the ideal shape for a productive plant, which is why trimming and shaping is an important part of growing marijuana.
You need to prune cannabis plants at every growth stage to achieve the most productive crop. In fact, there are specific techniques for each growing stage, and with a little practice, you’ll know exactly when and what to trim. Whenever you trim, only use clean, sharp scissors to protect your plants from disease and tissue damage from blunt cuts. There are multiple techniques to achieve the best shape, including:
- Foliage thinning
- Trimming for harvest
thinning out foliage on a marijuana plant
Trimming a plant helps it grow in multiple ways. First, by removing bulky inner leaves, you’ll increase airflow to the innermost layers of foliage. Second, this technique delivers more light energy to the remaining foliage and prevents moisture build up. More light and less moisture prevents mold, mildew, and pests from flourishing in the dark and damp conditions. Lastly, removing internal leaves will encourage root growth and healthy branching as your plant redirects energy to its outermost growth.
As your marijuana plant’s leaves grow larger, you’ll also need to remove some outer leaves from time to time to prevent them from shading the rest of the plant. It’s important not to remove too many of these, however, since they perform life-giving photosynthesis for the plant. With practice, you’ll refine your trimming technique to provide the perfect balance of airiness and robust foliage.
Along with regular thinning, you’ll also want to deadhead your plant as it grows. Deadheading is the process of removing leaves that naturally die off as the plant grows (this is a totally normal process). As long as the rest of your plant is healthy, then clipping this dead plant matter will help the marijuana plant avoid disease and spend energy where it’s most valuable to you: on healthy leaves and buds. A good rule of thumb whenever trimming or pruning is never to remove more than a third of your plant’s foliage at once to make sure it can continue capturing energy to maintain its tissues. After any type of trim, give the plant time to heal before picking up the shears again.
When the leaves get enough light and air, they help the plant grow strong, and strong branches will better be able to support the flower buds that will eventually grow for you to harvest. This is one of the reasons that many growers will start trimming their plants as early as the seedling stage. By training and shaping them early on, you can grow marijuana plants with a higher yield than un-trimmed plants would provide when they reach flowering maturity.
side note: identifying the gender of your marijuana plants
Pruning is a great opportunity to inspect the plant for its gender.
- Male plants have stamens on their stem nodes, which are small sacs filled with pollen.
- Female plants have pistils at these nodes, and whether they’re pollinated or not, they will grow flowers. If pollinated, they’ll be full of seeds (not good for harvesting).
If you catch and remove male marijuana plants from your crop early on, you can prevent them from pollinating the female plants, and they will produce seedless, usable marijuana buds.
topping a marijuana plant
Topping a cannabis plant helps control both the plant’s height and its horizontal spread. With this technique, a grower snips the top of the center stem with the purpose of redirecting energy and growth to its remaining horizontal branches. After topping your plant, these branches receive more direct light from above and can stretch upwards and outwards. Topping also helps to manage the aggressive vertical growth marijuana plants are known for: it’s common for these plants to reach up to 5 feet (and easily more without trimming) before they flower, especially when surrounded by other plants. Keeping the growth low and horizontal in this way results in more nodes and encourages eventual flower growth.
lollipopping a marijuana plant
Where topping is removing the top of the plant for lateral growth, lollipopping is when the lower branches on the plant are selectively removed so that the undercarriage doesn’t get too leafy, and the plant can focus growth to its upper portion’s branches and leaves. The resulting bare stem and leafy top looks like a lollipop. In grow tents, the light comes straight down from above, and although it’s still reflected by the tent walls, lower branches and inner leaves can be shaded by their own upper leaves as well as those of neighboring plants.
Removing the lower branches also keeps the plants from crowding each other in the tent. When the leaves of different plants start to touch, they’ll stop growing horizontally and focus on growing vertically into open space. If they do reach into each other and create a dense underbrush, moisture can build up and mildew, pests, or mold may grow in the shaded area.
when to prune a marijuana plant
Cannabis growers may have different preferences for when they start to top and prune their plants, but most will begin between a few days into the seedling stage (which lasts for two or three weeks) when the plant has at least 3 leaf nodes, or in the early vegetative stage. The plant needs to have some leaves before you start trimming since these are essential for photosynthesis.
You can trim marijuana plants throughout the vegetative stage up to about week 5. Between week 5 and the first week of the flowering phase, only lightly trim to ensure as many flowers come in as possible. When you decide to transition your plant into flowering, reduce your trimming altogether. You should only carefully and selectively trim away large leaves that are shading nodes in order to reduce damage to the bud sites at the base of leaves. Once the plant flips into flowering, it won’t regrow lost leaves since it will be focusing all of its energy on producing flower buds.
trimming cannabis buds for harvest
The term trimming is also used when referring to the last step in preparing marijuana buds to be ready for use: trimming back the leaf material on branches to expose the colas (groups of marijuana flower buds).
When the time comes for this final step, you’ll need to clip branches away from the main stem and dry them for a few days. At this point, the leaf material around the cannabis buds will be ready to be trimmed away. Wet trimming, or trimming weed without giving the branches time to dry out, can result in moisture buildup in your scissors, dulling the blade and creating not-so-clean cuts. Trimming dry buds after they’ve had a few days to sit is easier since the cannabis leaves will crumble off without leaving any moist residue.
You should take extra care when trimming buds to reduce damage to the trichomes on the flowers. Trichomes are the hair-like glands on the buds that secrete resin, which contains the cannabinoids THC, CBD, and over a hundred other compounds that make the green magic happen when consumed.
The flower buds grow at the stem nodes along the branch at the nodes, which you’ll see clearly as you cut more of the outer leaves and stalk material back. Trimming the leaves and stalk material is important because they don’t contain the compounds marijuana is known for, and typically contribute to a harshness if mixed in with smokable marijuana. The exception here are the sugar leaves, or the leaves closest to the buds that do indeed have trichomes and resin on them. Since you’re hand trimming, it’s easy to notice and set those in a separate pile away from the unusable material.
Use small pruning shears to make the most exact cuts and reduce damage to the plant. Hold the branches at the bottom of the stem when preparing to make cuts to avoid touching the buds themselves with your hands. Be sure to use sharp scissors for the cleanest cuts, and keep some paper towels handy to wipe off the scissors as you go. Sharp, clean blades will help you make precise cuts that don’t waste any of the bud’s flower material or damage the resin-soaked trichomes.
This is how to do it:
- Start at the bottom of your plant and clip leaves away in a spiral, making cuts in the direction of the grain of the leaf growth.
- Trim the fan leaves starting with the biggest first, working your way inwards to the center of the stem.
- Trim to the top of the plant.
- Once the extra material is removed, allow the trimmed buds to dry for another week before plucking them from the branch for use.