We don’t know about you, but the first signs of the flowering stage leave us positively giddy. They signify that we haven’t messed anything up and that we’re halfway to abundant yields of sticky buds.
Do you know when the flowering stage begins? For sure?
This growth phase is critical to the entire life cycle of your cannabis plant. Slip-ups can harm harvest quantity and quality while getting it right produces buds to write home about.
That’s why you should pay close attention to your setup when you see signs of flowering.
Join us for a complete overview of this happy time in a cultivator’s life. We’ll run through the stage week by week, letting you know what to expect throughout. We’ll finish with several tips for achieving dispensary-grade weed with simple gardening practices.
When does the flowering stage begin?
Weed plant stages refer to the types of growth that transpire from popping seeds to trimming and curing the buds. The entire cycle happens throughout seven stages, two of which are the most relevant for growers:
- The vegetative stage is when your cannabis crop develops stems, branches, and foliage. It builds the foundation for healthy flowering.
- The flowering stage is when your cannabis crop stops growing its green parts and focuses energy on bud production.
Since weed is a photoperiod plant, the first signs of flowering cannabis happen according to the hours of light it gets each day.
This process is a matter of nature. The plant’s internal processes dictate that it enters flowering when days get shorter. That way, it produces new seeds and continues its lineage before the cold winter days.
What does that mean for you? It means that you can induce the first signs of the flowering stage by introducing longer hours of interrupted darkness.
If growing outdoors without overt manipulation, this happens at the end of summer. Indoors, it’s as simple as flipping the light schedule to 10–12 hours of darkness per day.
Note: The first signs of the flowering stage for autoflowers happen when they reach a certain size. This variant doesn’t depend on light schedules and starts budding automatically.
Signs of flowering: A week-by-week overview
Once you see the first signs of weed plant flowering, it’s another 7–9 weeks before buds are fully mature. This figure is a rough estimate, varying between marijuana types, strains, seed variants, and climates.
The first three weeks are pre-flowering, the first sign of the flowering stage. Your plant starts showing signs of sex, rounds off its vegetative growth, and gets to cola production. After that, flowers emerge, fatten, develop a strong smell, and start enticing your senses.
With that in mind, let’s discuss the first signs of flowering, how long before buds appear, and how to best take care of your plant.
Note: The week-by-week breakdown discusses photoperiod plants. We’ve done a separate section on how to tell when an autoflower is flowering.
The initial week is all about intense vegetative expansion. The crop thinks that winter is nearing, and it starts stretching to carry the load of its buds. It’s not rare to see phenotypes double in size over that time.
For that reason, we often call this week the stretch phase. The signs of flowering in this time resemble vegging, making the crop greenery larger and stronger. Although this growth spur is the first sign of the flowering stage, you shouldn’t switch to blooming nutrients right away. Keep providing plenty of nitrogen for at least five more days.
The first signs of budding start at week two. Around this time, nodes between the main stem and fan leaves start forming pre-flowers.
How to tell if your weed plant is budding? The foliage around each branch turns upward and bunches up. White pistils emerge from their center, representing the origin of future smokable flowers.
Alternatively, you might notice small green sacs on the internodes. In that case, you’re dealing with male weed. You’re best off eliminating these herbs (unless you plan on breeding strains or producing new seeds).
It’s around this time you should introduce more phosphorus and potassium in your plants’ diet.
The third week is where your plant’s first signs of flowering weed get super obvious. The crop is about 50% bigger than it used to be. The stretching is either minimal or has halted completely as this week ends.
The pre-flowering weed already developed hairs in the internodes, but now, you might notice the initial signs of real flowers.
What do buds look like when they start to form? They’re round, chunky forms between the leaves and stem. Pistils poke out of the green structure, while resin glands and trichomes are practically non-existent.
This week is the ideal time to fully switch to bloom solutions. Don’t overdo it, though. Nutrient burn can harm your future harvest.
The signs of flowering remain pretty consistent in week four. The vegetative growth has likely stopped by this point. The flowers develop additional white pistils and grow larger and fatter. Trichomes start oozing, and you can already suspect what the finished product will smell like.
Bud growth depends on the variety. A sativa’s first signs of flowering stage take longer to show up. You might only now start seeing the first cannabis pistils. Indica specimens should already be teeming with bud sites.
By the time week five rolls around, we’ve surpassed the first signs of the flowering stage outdoors and indoors. You’re now seeing buds all over your plant, and they’re becoming thicker and more fragrant by the day.
In some specimens, the white pistil hairs might already turn darker, reaching a shade of light amber. The previously translucent trichomes are now opaque, indicating that the yield is near.
Weeks 6, 7, 8, and beyond
We’re combining the final three weeks’ signs of flowering because not all strains ripen at the same time. Rarely any cultivar is ready before week eight, though, and not many momentous developments happen throughout this time.
These last few weeks are your time to watch the buds fatten and do the final pre-harvest steps. Cut some leaves, turn up the grow lamps, and swat away at insects drawn by the resin.
The first signs of budding coming to an end also mean it’s time for weed flushing. If the flowering time lasts eight weeks, stop feeding crops in week number six. Provide plenty of clean water to wash away excess nutrients. Your buds will have a pure, untainted flavor.
Other than that, continue watching for issues and ripeness. The trichomes and pistils are telltale signs of harvest-ready plants.
How to tell when an autoflower is flowering?
Autoflower cannabis follows the same progression as its photoperiod counterpart. The only real difference is speed. In autoflowers, the first signs of the flowering stage emerge after around five weeks of vegging. The pre-flowering stadium is a week-long (instead of two or three), and bud fattening happens throughout the four that follow.
Despite these disparities, an auto crop develops buds and trichomes in the same way as a photoperiod one. Non-photoperiod marijuana tends to be harvest-ready by the fifth week that we discussed. That’s unlike photoperiods, which require around three more weeks to ripen.
Bonus section: Tips for an amazing harvest
Seeing the first signs of the flowering stage is thrilling, but rookies might find it intimidating! How do you get everything right in this vital development phase? Follow these simple tips to ensure your harvest is always top-shelf.
Sex plants early
Unless you got all-female cannabis seeds at Homegrown, plant sexing is necessary to avoid seeded, unsmokable weed. Sexing is easiest during the first and second weeks of budding.
In females, the first signs of the flowering stage are thin, wispy pistils. That’s what you want to be seeing. If there are small balls on the internodes, remove those crops to avoid pollination.
You don’t want to stop checking the sex after the first signs of flowering, either. Stress and suboptimal conditions might cause your canna ladies to turn into hermaphrodites. These rarities develop male and female parts and might fertilize themselves and the surrounding area.
Ensure healthy flowering
Prosperous pre-flowering weed means a healthy harvest down the line. Only change the light schedule when your crops are in good shape if growing indoors. It’s much harder to fix deficiencies and pest damage in budding plants.
Outdoor cultivators should pay extra attention to their garden in mid-summer. Noticing any yellowing leaves? Nip that issue in the bud to see signs of flowering on a thriving specimen.
You should also stop training and transplanting upon the first signs of the flowering stage. Both practices can stress the plants, create hermies, and diminish yield quality. Check our reports on transplanting cannabis and transplanting autoflower plants for more details.
Pre-flowering weed needs different temperatures, nutrients, and humidity levels than vegging plants. The new requirements also apply to plants deep into blooming. Changing the setup all at once stresses your weed, though.
The nutrients are the only factor under your control in the great outdoors. Gradually transition from veg to bloom solutions to minimize crop shock. Indoor growers can smoothen the transition even further. Instead of changing the lights, temps, and humidity all at once, do it bit by bit.
Start with temps and wait a day before lowering humidity. Once crops grow accustomed to these changes, it’s time to flip the lights and see the first signs of the flowering stage.
Get the conditions right
Speaking of conditions for plants displaying signs of flowering, here’s how to keep your blossoming crops humming in delight:
- Drop the relative humidity below 45% to prevent bud rot
- Keep the temperatures at 75°F during the day, and 65°F at nighttime
- Raise the CO₂ levels to 1,000–1,200ppm for vigorous blooming
Note: Some strains have different requirements from what we’ve listed. Read up on your cultivar of choice to stay on the safe side.
Switch up the lights
Indoor growers can take advantage of modern light technology for prolific yields.
Notably, pre-flowering weed likes orange and red lights, and its harvest-ready version also appreciates them. If possible, employ wavelengths at the 580–700 nm range.
Feed for blooming
Appropriate nutrient levels are vital for learning how to make buds bigger during flowering. You’re treading a thin line here, where underfeeding and overfeeding can both harm harvests.
As a rule of thumb, get generous with potassium and phosphorus when signs of the flowering stage become obvious. Use a pre-made fertilizer for accuracy and stop feeding if you notice any symptoms of nutrient burn.
Trim excess foliage
Training and trimming are no-nos for crops exhibiting the first signs of flowering. An all-encompassing trim job before that time is a good idea, though. It minimizes the energy expenditure of the crop, boosts light exposure and aeration, and directs nutrients to future bud sites.
Remove all unproductive foliage and stems. Aim for large leaves that shade the plant and short, semi-developed branches. While you’re at it, cut the yellow and dead leafage.
Support heavy branches
Flowering crops often buckle under the weight of their buds, particularly if you’re cultivating slim sativa specimens.
You can give them a helping hand by stringing bamboo stakes to branches. Such support prevents bending and snapping, which can harm the crop.
Know your harvest window
Knowing when to harvest cannabis is key to getting potent buds. Combine the expected flowering duration for your strain with its existing visual aspects.
The signs of flowering completion include brown, curled pistils and opaque clarity in trichomes. These traits guarantee that you gather buds at their highest THC levels.
Understanding the first signs of the flowering stage and how it moves onward is key to providing proper care and diagnosing issues as they emerge.
Let’s recap what we’ve learned:
- Weeks one to three are pre-flowering, the first signs of the flowering stage. Plants grow vigorously and then halt, with pistils popping up.
- Weeks four and five are where the pistils get darker, real buds develop, and trichomes cover their surface.
- Weeks six, seven, eight, and beyond help buds fatten and ripen. Autos are usually harvest-ready after week five, while photoperiods need at least three more weeks.
Use our overview to monitor your crops and notice if anything’s gone awry. Apply the pre-harvest tips to ensure prosperity in every future growth patch.
Why not put your new knowledge to the test? Get seeds at Homegrown and plant them in your garden. Experience the theoretical descriptions in practice and apply our tips for optimal results.
Stay tuned to the Homegrown blog for more guides like this first signs of flowering summary. Our educational resources are with you every step towards a prolific weed yield.
About the author: Parker Curtis
Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.