Quick answer: Top your cannabis plant after the 6th node appears, which is typically 4 to 5 weeks from germination. Sterilize a pair of sharp trimming scissors, cut cleanly between the 5th and 6th nodes, then remove all growth from the 1st node. That leaves 4 nodes with 8 future main branches. Always transplant into the final pot before topping, never top during flower, and expect a 3 to 7 day recovery before visible new growth resumes.
Topping is the single highest-leverage move you make in the vegetative stage. Done correctly, it converts a tall, single-cola Christmas tree into a multi-cola plant ready to fill your grow space and translates directly into more weight at harvest. Done incorrectly, it stunts the plant, invites pathogens, or triggers a hermaphrodite response. This guide covers when to top, how to top step-by-step, autoflower-specific rules, topping vs FIMing, multi-topping for larger setups, and the peer-reviewed plant science behind why it works.
If you do not top a cannabis plant, it grows the way evolution designed it: tall, skinny, with one dominant top cola and a handful of weak side branches. That shape is great for a plant trying to outgrow its neighbours in a wild field. It is the wrong shape for a plant in your tent or backyard, where you have full control over light, water, and space and you want every gram of bud the plant can produce. Learning how to top cannabis is the first move that changes plant shape from "what nature gave you" to "what your grow space rewards" - and it is the move that separates a 0.5 oz autoflower from a 4 oz one.
This guide assumes your seedling is healthy and recently transplanted. If you are earlier in the cycle, start with our how to germinate cannabis seeds, how to plant cannabis, and how to transplant cannabis guides. For the science of how the trained canopy actually converts light into bud, see our canopy development science article.
When to Top Cannabis
The best time to top your cannabis plant is when the 6th node has just appeared and is still small (a node is a pair of branches and leaves growing 90 degrees apart on the main stem). At that point you have 5 fully formed nodes with the 6th still pointing upward and not yet developed. From germination, this usually takes 4 to 5 weeks for a healthy photoperiod seedling.
The smaller the 6th node when you cut, the less plant material you remove and the faster the plant recovers. If you wait until the 7th node has fully developed, you are removing significantly more biomass and risking real stunting. To dig deeper into how the canopy develops in response to topping, read our canopy development science guide.
Transplant Before Topping
Stacking two high-stress events back to back is a common beginner mistake. Transplant first, give the plant 5 to 7 days to settle and push fresh roots into the new media, and then top. A well-rooted plant has the energy reserves to redirect into lateral growth almost immediately, while a freshly transplanted plant does not. The pop-out bottom plate on a starter cup like the BudCups makes the transplant itself shock-free, so by the time you top, the only stress event the plant is dealing with is the cut itself. The full transplant procedure is covered in our how to transplant cannabis guide, and the BudCups-specific workflow is in our how to use the BudCups guide.
Never Top During Flower
The flowering stage is for bud production, not branch development. Topping during flower diverts energy away from inflorescences, reduces final yield, and significantly raises the risk of hermaphroditism (the plant producing male pollen sacs in response to the stress, which can self-pollinate the female flowers and ruin the harvest). Always finish topping at least 5 days before you switch the light schedule to 12/12.
How to Top Cannabis - Step by Step
Once the 6th node is visible and the plant has fully recovered from its transplant, the procedure itself takes about 30 seconds. The two things that matter most are clean tools and a clean cut.
What You Will Need
- Sharp, thin-tipped trimming scissors (thin tips matter for not damaging the small growth sites that sit just below the cut)
- Rubbing alcohol or isopropyl, plus a clean cloth or paper towel
Step 1 - Sterilize and Make the Cut
Wipe the blades of your scissors with rubbing alcohol. Dirty tools introduce pathogens through the fresh wound, which slows recovery and can cause infection at the cut site. This takes 10 seconds and matters.
Cut cleanly between the 5th and 6th nodes, leaving 5 nodes (10 small branches and leaves) on the plant. The cut should be straight across the stem, slightly above the 5th node, with the 6th node and any growth above it removed in one piece.
If the 6th node is small, this cut removes very little plant material and the recovery is almost invisible. If you waited too long and the 6th node has developed substantial leaves and a 7th node above it, you are removing a meaningful chunk of the plant and recovery will be slower. Top early when the 6th node is still small and harmless.
BudTip: Protect the Small Growth Sites
When you top close to the 5th node, the small growth sites at that node have already started to emerge - and they are exactly what becomes your new main branches. Damaging them on the way through is a real risk, especially with thick-tipped pruners. To avoid it, gently bend the 6th node sideways before you cut, which moves the tip of the scissors away from the 5th-node growth sites. Thin-tipped pruners help here too. Treat those small sites like the future main stems they are.
Step 2 - Remove the 1st Node
Once the top is off, take both leaves and the small growth sites at the 1st node off the plant. The 1st node sits closest to the soil, never receives enough light to develop into a strong branch, and never produces a meaningful cola. Removing it redirects energy to the 4 remaining upper nodes, where you actually want it.
You should be left with a plant that has 4 nodes, 8 future main branches, and 8 leaves. Those 8 growth sites are now the primary structure of the plant. Every training move you make for the rest of the vegetative stage builds on this base, and every gram you weigh out at harvest traces back to it.
What to Expect After Topping
For the first 3 to 7 days after topping, upward growth pauses while the plant redirects auxins (its primary growth hormone) from the removed apex to the lateral branches.1 The plant looks like it has stopped growing. It has not - it is rebuilding the hormone gradient that drives the next phase of development.
During this window, do not stack additional stress on the plant. No transplanting, no light schedule changes, no LST, no defoliation. Keep watering and feeding on the same schedule as before, though the plant may drink slightly less in the first 2 to 3 days. That is normal.
You should see visible new growth from the top two nodes within 5 to 7 days. Once those new growth sites reach roughly 2 inches in length, the plant is ready for the first stage of low-stress training, which is usually done with BudClips on the main stem and BudHuggers on the outer branches. The full training procedure is covered in our how to train cannabis and low-stress training guides.
How to Top Autoflowers
Conventional advice says do not top autoflowers. The argument is that autoflowers have a fixed lifecycle, so any stall caused by topping eats directly into yield with no opportunity to recover. We have tested this in our own grows, and the conclusion is more nuanced: topping autoflowers works, but the timing window is tighter and the cut has to remove less material than it would on a photoperiod.
The rule for autoflowers is the same as photoperiods - top between the 5th and 6th node when the 6th is still small - but the consequence of waiting too long is more severe. With a photoperiod plant, you can extend the vegetative cycle by an extra week if needed. Autoflowers do not give you that option. If you miss the window and the 7th node has appeared, skip topping entirely and run that plant untopped, training it laterally with LST instead.
Done at the right time with minimal material removed, autoflowers spring back within 2 to 3 days and continue their cycle as if nothing happened. The autoflower below was topped at the 5th node and turned out to be the largest auto we have ever grown.
For autoflower-specific training after topping, see our low-stress training guide. Autoflowers respond particularly well to LST because the technique is non-invasive and adds zero recovery time.
Topping vs FIMing
Topping and FIMing (short for "Fuck I Missed", coined by an outdoor grower who botched a topping cut and got a useful result anyway) are both high-stress training techniques that break apical dominance. They produce different outcomes and are worth understanding before you pick one.
Topping is a clean, full cut that removes the entire growth tip above a node. It produces 2 new main branches at the cut site reliably, recovery is 3 to 7 days, and the resulting branch structure is even and easy to train.
FIMing removes only about 75% of the growth tip, leaving a small amount of meristem tissue behind. It can produce 3 to 5 new growth sites from a single cut - more colas in theory - but the new branches grow at uneven heights, which makes maintaining a flat canopy harder. Recovery is slightly faster (3 to 5 days) because less tissue is removed.
For most home growers, we recommend topping over FIMing. The branch structure is cleaner, the canopy is easier to manage with BudClips, and the predictability matters more in a small grow space than the extra 1 or 2 colas FIMing might produce. If you have a large outdoor space and want to maximize cola count without precise control, FIMing is worth experimenting with - but build the muscle memory on topping first.
Topping More Than Once
Yes, you can top more than once. Whether you should depends on how much space you are giving each plant.
Second Topping (6 to 8 sq.ft. per plant)
If your plant has 6 to 8 sq.ft. of canopy space, top each of your top 4 main branches a second time, 1 to 2 weeks after the first topping. This is the next stage of the BudTrainer Method and is covered in detail as Stage 2 of our how to train cannabis guide.
The second topping happens on the 4th or 5th node of each branch, since the 2nd and 3rd nodes never develop into strong branches. Each topped branch then produces 2 more main branches, which means a single plant can carry 16 to 32 future colas after two toppings. Combined with proper LST, that is what produces the dense, even canopies you see in commercial flower rooms.
If you have 4 sq.ft. or less per plant, do not top a second time. Stick with one topping, train laterally, and switch to flower at week 6 to 7 from germination. A second topping requires extending vegetative growth to weeks 7 to 8, and that extra time is not worth it in a small space - the plant will simply outgrow what you can manage.
Third or Fourth Topping (15+ sq.ft. or outdoors)
For outdoor growers or anyone with 15+ sq.ft. per plant, a third or fourth topping (1 to 2 weeks apart) is on the table. This is the foundation of the mainline training and manifolding methods, where the plant is topped repeatedly to build a perfectly symmetric, tree-like structure with 8, 16, or 32 main branches. The plants below were topped four times using the mainline method.
Why Topping Increases Yield - The Science
Most grow guides tell you topping increases yield without explaining why. The why matters, because once you understand it, you can apply the same principle to FIMing, mainlining, manifolding, and any other training technique that breaks apical dominance. There are three things going on at once.
Survival, Reproduction, and the Christmas Tree Shape
Picture a wild field with thousands of cannabis plants competing for the same sunlight and pollination. To survive, each plant has to access water, CO2, and light. To reproduce, each female plant has to position its flowers high and exposed enough that wind-borne male pollen can reach them.
That selection pressure is why cannabis grows tall and skinny by default rather than short and bushy. From the plant's evolutionary perspective, one massive exposed cola at the top of a tall stem is a better bet than 100 smaller colas distributed across a wide canopy. The first one almost guarantees pollination. The second one almost guarantees being shaded out by neighbours.
Breaking the Pattern in Your Grow Space
Indoors or in a controlled outdoor setup, neither of those constraints applies. Your female plants are not supposed to be pollinated (you want seedless flower), and they have all the water, light, and space they need without competing. The single tall cola the plant evolved to produce is now the worst possible shape for your goals - it wastes most of the canopy footprint and leaves most of your light hitting bare stem instead of bud.
Topping rewrites the plant's structural plan. Instead of one dominant cola, you get 8 (or 16, or 32) main branches that all share the canopy footprint roughly equally. Total bud production goes up at harvest, average bud size stays similar, and the overall canopy becomes flat and easy to manage with low-stress training.
Auxins and Apical Dominance
The hormonal mechanism behind this is well documented. The dominant growing tip of a cannabis plant produces high concentrations of a hormone called auxin (technically indole-3-acetic acid or IAA), which is transported downward through the stem and suppresses the outgrowth of axillary buds (the small growth sites that sit at every node).1 This is why an untrained cannabis plant ends up tall and skinny - the apex keeps producing auxin, which keeps the side branches small.
The same auxin signal also drives phototropism. When light hits one side of a stem, auxin redistributes to the shaded side, causing the cells on that side to elongate faster than the lit side, and the stem bends toward the light.2 This is why bending a branch sideways during LST eventually causes it to grow back upward - you have shifted the auxin gradient, not removed it.
Shifting the Hormone Gradient
When you top a cannabis plant, you remove the apical meristem - the source of most of the plant's downward auxin signal. The suppression of axillary buds collapses, and the lateral nodes immediately below the cut start producing their own auxin and growing as if they were independent main stems.1 A single dominant cola becomes two co-dominant colas, and the plant rebuilds its canopy from the new gradient.
Cannabis-specific research backs this up. A 2022 controlled greenhouse study at the University of Hohenheim found that topping a chemotype III medical cannabis plant produced significantly higher inflorescence dry weight and total leaf area compared to unpruned controls, driven by the increased number of secondary shoots that follow apical removal.3 The mechanism is the same as in every other branching plant studied - cut the apex, the auxin gradient resets, and the plant rebuilds with more, smaller branches that share the photosynthetic load.
That is the whole story. You are not "telling the plant to grow more buds." You are removing one hormone source so the plant has to build new ones, and in doing so it produces a structure that fits your grow space far better than the one evolution gave it.
Frequently Asked Questions
When should I top my cannabis plant?
Top after the 6th node has just appeared and is still small, which is typically 4 to 5 weeks from germination. You should have 5 fully formed nodes plus the 6th still emerging. Cutting earlier removes too little of the apex to fully break dominance; cutting later (after the 7th node has developed) removes too much plant material and slows recovery.
How long does it take a cannabis plant to recover from topping?
Most plants recover in 3 to 7 days. During this period, upward growth pauses while the plant redirects auxins from the removed apex to the lateral branches. You should see visible new growth from the top two nodes within 5 to 7 days. Avoid additional stress (transplanting, schedule changes, training) until that new growth is at least 2 inches long.
Can I top autoflowers?
Yes, with tighter timing. Top autoflowers between the 5th and 6th node while the 6th is still small, just like photoperiods. The difference is that you cannot recover from a late or aggressive cut by extending vegetative growth, so if you missed the window and the 7th node has fully developed, skip topping and use low-stress training instead. Done correctly, autoflowers spring back in 2 to 3 days.
How many times can I top a cannabis plant?
It depends on space. Indoor growers with 6 to 8 sq.ft. per plant should top twice. With less than 4 sq.ft. per plant, top only once. Outdoor or large-canopy growers (15+ sq.ft. per plant) can top 3 or 4 times using the mainline or manifold method. Each additional topping doubles the cola count but extends vegetative growth by about a week.
What is the difference between topping and FIMing?
Topping is a full cut that removes the entire growth tip and produces 2 new main branches reliably. FIMing removes only about 75% of the tip, can produce 3 to 5 new growth sites, but the new branches grow at uneven heights. Topping recovers in 3 to 7 days; FIMing in 3 to 5. For most home growers, topping is the better choice because the branch structure is cleaner and easier to train.
Should I sterilize my scissors before topping?
Yes, always. A 10-second wipe with rubbing alcohol prevents bacteria and fungal pathogens from entering the fresh wound. The cut site is essentially an open injury - exactly the kind of entry point that pathogens evolved to exploit. Skipping this step is one of the most common ways topping leads to infection or stem rot.
Why should I transplant before topping?
Stacking two high-stress events back to back overwhelms a young plant. Transplanting first and waiting 5 to 7 days lets the plant build a strong root system in its new container, which gives it the energy reserves to redirect into lateral growth as soon as the apex is removed. A well-rooted plant recovers from topping in days; a freshly transplanted one can stall for a week or more.
What happens if I top during flowering?
Two bad things. The plant diverts energy from bud production back into branch development, which permanently reduces yield. And the stress of topping during flower significantly raises the risk of hermaphroditism - the plant producing male pollen sacs that can self-pollinate the flowers and produce seedy bud. Always finish all topping at least 5 days before switching to a 12/12 light schedule.
Does topping increase yield?
Yes, when combined with proper training. Topping itself does not directly create more bud - it creates more bud sites. To convert those sites into actual yield, you have to spread them across the canopy footprint with low-stress training so they all receive similar light. Peer-reviewed cannabis research has confirmed significantly higher inflorescence dry weight in topped versus unpruned plants.
What if my plant has more than 6 nodes already (I missed the timing)?
For photoperiods, you can still top - just cut between the 5th and 6th node and accept that you are removing more material than ideal, with a slightly slower recovery. For autoflowers that have already grown past the 6th node, do not top. The recovery cost is too high relative to the fixed lifecycle. Train laterally with LST instead.
Should I water before or after topping?
Water on your normal schedule. Topping does not change the plant's water needs in either direction. Some growers report a slight dip in water uptake for the first 2 to 3 days after the cut as the plant pauses upward growth, which is normal. Do not flood the pot trying to "help" the plant recover - overwatering after a stress event makes things worse, not better.
Can I use the topped piece as a clone?
Yes. The piece you cut off is essentially a free clone. Trim it down to a 4 to 6 inch cutting with one or two pairs of leaves, dip the bottom in rooting hormone, and plant it in a starter cup. Roots typically appear within 7 to 14 days under high humidity (75 to 90%). The clone will be genetically identical to the mother and at the same age, which is useful for preserving a phenotype you like.
How long after topping before I can start LST?
Wait until the new growth sites at the 5th node are at least 2 inches long, which is usually 5 to 10 days after the topping cut. Starting LST earlier means bending stems that are still too tender to hold a position, and you risk snapping them. Once they reach 2 inches, the side branches are flexible enough to position with BudClips without breaking.
Do I need to top my cannabis plant at all?
Not strictly. A plant grown without topping will still produce flower - it will just be a tall, single-cola plant with weak side branches and most of its yield concentrated in one place. If you have a tall grow space, are running an autoflower in a small pot, or simply prefer a hands-off approach, skipping topping is a valid choice. Yield will be lower than a topped and trained plant, but the plant will still finish its cycle.
Next Steps: After Your First Topping
Once you see new growth sites at the 5th node reaching about 2 inches in length (usually 5 to 10 days after topping), the plant is ready for the first stage of low-stress training. That is where you take the 8 future main branches and spread them outward to build the flat canopy that converts your topping work into actual yield. Most of that work is done with BudClips on the main stem and BudHuggers on the outer branches, anchored to the grommets on a fabric pot like the BudPots. If a branch ever snaps under tension, BudTape repairs it cleanly.
Read next:
- How to Train Cannabis Plants (Step-by-Step Guide)
- How to Low-Stress Train (LST) Cannabis
- How to Use BudClips for LST
- How to Manifold Cannabis Plants
- How to Mainline Cannabis Plants
- How to Defoliate Cannabis
- Cannabis Canopy Development Science
- How to Harvest Cannabis
- How to Dry Cannabis (the 60/60 rule)
- How to Trim Cannabis
- How to Cure Cannabis
Topping is the hinge that turns a wild-shape cannabis plant into a grow-space-shape one. Get the cut right, give it 5 to 7 days, and the rest of the BudTrainer Method has the structural foundation it needs to work all the way through to a clean harvest, a slow, terpene-preserving dry, a clean trim, and a proper jar cure.
References
- Beveridge, C. A., Rameau, C., & Wijerathna-Yapa, A. (2023). Lessons from a century of apical dominance research. Journal of Experimental Botany, 74(14), 3903-3922. https://academic.oup.com/jxb/article/74/14/3903/7131422
- Christie, J. M., & Murphy, A. S. (2013). Phototropism: Growing towards an understanding of plant movement. The Plant Cell, 26(1), 38-55. https://academic.oup.com/plcell/article/26/1/38/6102330
- Crispim Massuela, D., Hartung, J., Munz, S., Erpenbach, F., & Graeff-Hönninger, S. (2022). Impact of harvest time and pruning technique on total CBD concentration and yield of medicinal cannabis. Plants, 11(1), 140. https://www.mdpi.com/2223-7747/11/1/140
About the Author
Henrique Dias is the CEO and co-founder of BudTrainer. He is a mechanical engineer who also holds a graduate certificate in Commercial Cannabis Production from Niagara College in Ontario, Canada - the first college-level cannabis cultivation program in North America. Before founding BudTrainer, Henrique worked with Health Canada licensed cannabis producers, where he gained hands-on experience in cultivation, processing, and post-harvest management of cannabis at commercial scale. He started BudTrainer to bring that same level of craft to home growers through better-designed gardening tools and clear, science-backed education.
DISCLAIMER: Everything taught and sold by BudTrainer® is to be used strictly for legal purposes. We do not endorse 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.
