Cannabis flowering stage: a guide for beginners
In this article, you can find information about Cannabis flowering, week by week, with photos and pictures. The flowering stage in Cannabis plants is the period when plants grow their buds. After some weeks of vegetative growth, Cannabis plants will be able to flower when the photoperiod switches. Learn how to take care of your plant in this stage to harvest quality buds!
When does the Flowering stage begin?
Flowering stage outdoors
Growing outdoors, plants will start the flowering stage when the days grow shorter, usually when Autumn is coming.
Flowering stage indoors
For Cannabis plants to enter the flowering stage in indoor crops, the photoperiod must be switched to 12 12-hour light / 12 hours of darkness schedule.
Autoflowering strains don’t need a photoperiod change to start flowering, their vegetative stage lasts around 4 weeks and then they switch stages automatically.
How long does the flowering stage take?
The duration of the flowering stage varies among different strains.
The flowering stage in Cannabis plants usually goes from 8 to 11 weeks, depending on the strain. It’s usually divided into weeks or three stages. The flowering period for Indica labeled strains is typically around 8 weeks, but it may take up to 10 weeks. Sativa-labeled strains may take up to 10-12 weeks. Typically, hybrid strains will take up to 6-10 weeks to fully develop.
How do I know if my plant is male or female?
Here’s a quick visual guide on how to tell if your Cannabis plant is male, female, or hermaphrodite. For more information and tips on how to find out, read our full article on determining the sex of a Cannabis plant.
Basic growing requirements for flowering Cannabis plants
Lighting
Light is very important in every stage of the Cannabis plant life cycle, but in the Flowering stage is key to keep a Photoperiod: 12 hours of light / 12 hours of darkness. Do not interrupt the dark periods by opening “just for a sec” your growing environment. Light pollution may cause your plant to slow the budding process or even to revegetate (go back to the veg stage) or start producing hermaphrodite flowers.
Temperature
Cannabis plants in the flowering stage thrive in temperatures around 18° – 26°C. Temperatures below this range may negatively affect the plant, or even kill it if it’s exposed to freezing temperatures for a long period. Temperatures under 17°C may slow the plant’s growth and very low temperatures (under 2°C) may damage the plant irreversibly. On the other hand, high temperatures negatively affect the plant as well. Temperatures over 28° C may cause problems such as stunted growth, burnt leaves, excessive water evaporation, excessive dryness, etc.
Humidity
As well as keeping temperatures within those “warm” ranges, taking care of the relative humidity in the growing environment is key. Relative humidity measures how much humidity is present in the air expressed as a percentage.
Humidity must be kept ideally between 40-50% in this stage. Higher levels of humidity may cause problems such as mold and fungi. Learn more about fungal diseases reading this article: https://growithjane.com/fungi-cannabis-plants/
Nutrients for Cannabis plants in the flowering stage
The main nutrients that the Cannabis plant needs to develop are Nitrogen (N), Phosphorus (P), and Potassium (K).
When the plant starts to bloom, the concentrations of P and K must be increased progressively, while the N concentrations are lowered. That is why there are specific fertilizers for vegetative growth and flowering.
Other secondary nutrients will be necessary for the correct development of the plant. These are Magnesium (Mg), Calcium (Ca), and Sulfur (S). Finally, the micronutrients are necessary but in a minimum concentration. These are Zinc (Zn), Manganese (Mn), Iron, (Fe), Boron (B), Chlorine (Cl), Cobalt (Co), Copper (Cu), Molybdenum (Mb), and Silicon (Si).
So which is the best feeding plan or nutrient application schedule for my plant? That’s up to each grower, but bear in mind you’ll need to add these nutrients, via foliar, liquid, or solid fertilizers. Even when growing organic, usually having your plant in plain soil is just not enough for the plant to produce big fat buds.
Several brands of fertilizers offer fertilizer kits specially formulated for each stage with the necessary nutrients. Start with the dose indicated by the manufacturer or even 1/2 lower to avoid saturation and gradually increase the amounts until the desired results are achieved.
Read this article to learn more about nutrients for Cannabis plants in the flowering stage.
Watering
Water your plant regularly with clean, safe water. Certainly, using chlorine-free or filtered water leads to better results. Always avoid overwatering and watch for good drainage. How to know when to water a Cannabis plant? A good test might be to stick a finger down a few cm or an inch into the soil and if it’s dry, then you’ll know it is time to water.
Ventilation
Ventilation and airflow are key for Cannabis plants to thrive and grow healthy. In this stage, they need air not only to breathe and grow their bodies but also good ventilation to avoid the formation of mold, fungi, and rot. A good fan moving the air inside your growing environment helps a lot, but beware not to point it directly at the buds. An exhaust fan is great for increased ventilation and air movement, this also helps lowering humidity. If the exhaust fan is not enough, a dehumidifier is the best and easiest solution for keeping humidity at range.
pH levels
pH levels must remain between 5.5 and 6.5 when growing in soil. Most nutrients are available for the plant in the growing medium only between this range of pH. pH levels out of this range may cause your plant to experience nutrient deficiencies and toxicities because the nutrients may be in the soil but the plant cannot absorb them.
Container size
The size of your container is always related to the plant’s size. Are you growing in your garden soil? In pots with soil? In buckets? Hydro? The bigger the container, the more chances you have to get a bigger plant. Remember to transplant your tree before the flowering stage begins to avoid stressing the plant or accidentally damaging it.
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Flowering stage in Cannabis plants week by week
Flowering initiation stage – week 1-3
From week 1-3 plants stretch and grow in size and height. This phase is also known as the transition phase, as plants experience drastic changes these days. Plants stretch and may double their size in this phase. The female Cannabis plant starts blooming by producing pre-flowers, their pistils look like “white hairs”.
Towards the end of the third week, the plant starts forming its bud sites in the plant nodes (where the main stem and the branches meet). Look for clusters of female preflowers.
All those places where white pistils have been growing are future bud sites. If you accidentally cut the preflowers along with the fan leaves, there’s a chance that that bud will stop growing. You may lightly defoliate your plant during this phase, but be careful not to touch or damage the forming bud sites.
Look at the color of the fan leaves and the general look of each plant to have a better idea of their health and needs. The fan leaves should be vibrant green, not too light or dark. For example, yellow and discolored leaves may indicate a deficiency, while dark and clawing leaves may indicate nutrient burn. Track these changes in the Grow with Jane app as soon as you notice them for a better chance of diagnosing your plants correctly and in time to heal them!
It’s also important to check for pests, mold, and fungi before our plants start making their buds. Most importantly, eliminating these at this point is usually easier than doing it later in the flowering stage.
Learn more about pests in cannabis plants https://growithjane.com/pest-cannabis-plants/
Learn how to get rid of pests in cannabis plants https://growithjane.com/bugs-cannabis-plant/
Mid-Flowering stage – week 4-5
From week 4-5 plants stop growing in size and start growing, fattening their buds and darkening their pistils.
- Humidity levels need to be lowered to 40-50%
- It’s best to slightly lower temperatures in flowering
- Temperatures with lights on 18-26 ° C (avoid high temperatures)
At this stage, you should continue to train your plant if you started some weeks earlier and you should be seeing some changes. In addition, if you need to tie or move your plants, remember that now they are putting all their efforts into growing buds, so any stress or damage may slow that process.
Remember to continue to move your lamp or plants so they maintain their adequate distance. Now your plants are growing at a fast rate and they need their feeding and watering schedule to be followed for optimal results.
It’s normal at this phase to see some old leaves yellowing and finally turning brown and falling. That’s because some nutrients are “mobile”, meaning that once the plant has absorbed them, they can be stored and distributed inside the plant as needed. So an old leaf may “send” nutrients to the newer ones and once the plant doesn’t need that leave anymore, it lets it die and fall. If you notice lots of leaves yellowing or any changes in color or texture in the new or old leaves, check for nutrient deficiencies or burn!
Late flowering / Ripening stage – week 6 to harvest
In the last few weeks, buds have gained the most weight. They are sticky to the touch and can be very smelly. You are very close to reaching your goal = harvesting!
- Bring down humidity levels: 45% if possible
- Increase the temperature difference (day/night)
- Temperatures with lights on 18-24 °C
- Start checking trichomes for signals or ripening to know when to harvest
- You can flush your plants 1-2 weeks before harvest
Most importantly, buds are now covered in trichomes, which are rich glandules for secreting THC and other cannabinoids. These are responsible for the stickiness in the colas. Depending on the strain and the breeding, these buds may have strong aromas, reminding of fruits, flowers, and spices for example.
In this stage of the Cannabis plant, pistils may show white, cream, and brown colors. They also start curling inwards and they get covered in trichomes. Similarly, trichomes also change colors and you should pay close attention to these changes because they are one of the best clues for knowing when is the best time for harvesting.
Flushing your plants (week 8-10)
Flushing a Cannabis plant is running a lot of water through its growing medium (soil, for example) to get rid of the excess salt and mineral nutrients. This action forces your plant to use up any amount of nutrients previously absorbed. The result will be buds with better flavor and aroma. The excess fertilizer in your Cannabis plant may result in buds that are harsh to the throat when smoked. Flushing with clean, room temperature water will help to get rid of fertilizer excess in the soil.
Two weeks before harvesting is usually a good moment to start flushing your plants and watering with water only and no fertilizers until the harvesting moment. You can water with 10%-20% more water than usual and see how your plants react, they shouldn’t look droopy and should recover soon. The excess water will slowly drain from the bottom of the pot.
A good visual sign is that, in the beginning, the water coming from the bottom of the pot will be dark and will gradually turn to a lighter color. By running this process in each plant, most of the salt buildup should flush away from the substrate.
Even though lots of fertilizer companies recommend flushing plants for two weeks before harvesting, many growers nowadays choose to avoid flushing altogether and still have good results. It’s a matter of personal choice and one must evaluate the growing conditions, the nutrient schedule, and the final results.
Harvesting Guide
Read the following article to learn exactly when to harvest your flowering plants, how to tell if they are ready by looking at trichomes and pistils, how to dry and cure your buds, and more! All are explained thoroughly, with pics and a Step-by-step harvesting guide.
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What about flush if you use living/super soil compounds? Do you still have to do it?
Hi! Joshua!
If your plant is showing clear signs of nutrient burn, you should definitely do it.
If it was grown organically it may not be necessary.
If you haven’t applied any mineral nutrients it’s up to each grower if flushing is needed or not. Some growers swear by it and some just skip this process.
Thanks for reading and commenting! Have a nice day!
What are the effects on my yield if my plant flowers early?
Hi Juanette! The duration of the flowering period is more important to achieve a higher yield and even higher THC concentrations. Harvesting just in time, not early nor later, will have more impact on the quality of your flowers. The rest may be up to environmental conditions, especially if growing outdoors. If weather conditions are harsh in your area in Autumn, it’s a good thing to have your plant flowering early. This means you may harvest sooner than later and avoid strong winds, rain, or even snow, which may damage outdoor crops severely. Follow a nutrient schedule for the flowering stage and avoid interruptions in the hours of darkness if growing indoors.
My leaves a changing to purple n orange its outside i live in florida ive never put chemicals what so ever whats your recommendation my buds are beautiful smell great just fist time grower
Hi! If your plant looks good overall and there are only changes in the leaves going purple/orange, it could be due to strain features. There are Cannabis phenotypes that show orange and purple on the leaves and buds. Drops in temperatures sometimes trigger these changes. There’s a chance that harvesting is near so start monitoring your trichomes with a magnifying glass! If trichomes are still transparent, wait a few more days and check again until you start seeing white trichomes, maybe some of them amber. Then you’ll be ready to harvest! Thanks for reading and happy harvesting!
My plants are photosynthesis and are in either 7 + 8 or a and 9 I’m not sure is there anyway I can upload pictures to show you guys so you can tell me
Hi Brandon! Please, upload your images to the Grow with Jane app and I’ll be happy to take a look at your Growlog!
Hey everyone…started them late not until june didnt get very big ..especially because i didnt use any chemicals except for the spider mite killer..they look great not big but nice buds..if I havent used any chemicals do i still need to flush??
Hi Robin! There’s no need to flush your plant if you’ve been growing in soil and haven’t applied any fertilizers.
I hope you enjoy your harvest! Thanks for commenting!
What are trichones
I got my plant when it was dead and I planted it in the ground and watered it and it took off I don’t smoke much weed yet but I think my plant is a girl nor sure what kind I think it’s indica but it’s only a couple months old I think it’s starting to form buds. Can I uproot it and bring it in the house or is it fine outside I’m really new at this
Hi Honey, if the plant is outside and starting to form buds, it’s better to leave her outside. Uprooting a grown plant and changing the environment could damage her. You can protect your plant from frost if the size permits it. Street lights might delay or “confuse” your plant so consider covering her from unwanted lights at night. For personalized advice about your plant, please send us an in-app message from the Grow with Jane app and our Grower Support team will be happy to help! Thanks for reading and commenting, happy growing!
Hi Honey, trichomes are small resin glands (that “frost” on the buds). They look like little lollipops when you look at them with a magnifying glass. Cannabinoids and terpenes (aromatic compounds) grow in the trichomes, that’s why they are important. In this article, I explain how to look at trichomes to know when to harvest your plant. https://growithjane.com/how-to-harvest-a-cannabis-plant/
I hope this helps! Happy growing!
I’m growing in a DWC system. I started flowering, and one of my plants has started budding but are not filling out and the leaves are curling up. What do I do?
Hi Herman! Curling leaves may be caused by very high temperatures (heat stress) and/or overfertilization. To get personalized advice on your case, please download our app from http://www.growithjane.com and contact us via in app message, so you can also share pics and any info you think would be helpful. We’ll be happy to take a look! Thanks for commenting and happy growing!
Can u veg with full spectrum lights
Hello, yes you can! Some panels have veg and flower switches for adapting to each stage. Always set to 18 hours of light and 6 hours of darkness for veg stage.
Thanks for contacting Grow with Jane, have a nice day!
Alicia
Pushing plants to flower stage since its been 10 weeks. ( Sativa). 12 hours on and 12 hours off. Lights are blue and red. Veg / bloom.
Its been 2 weeks and I dont see any signs of hairs. How long does it take?
No discoloration on leaves. Proper nutrients and ph balanced water. Temp 78 degrees humidity 48.
Hi! Some Sativa strains may take more time to develop and start flowering. Most plants start showing preflowers in the first or second week after switching, this might take a little longer.
Add nutrients intended for the flowering stage, as nutrients for veg have high levels of Nitrogen and this may delay and hamper flowering. Temperature and humidity are fine, keep them that way. Make sure that the dark periods are completed without any interruptions or light filtrations, this may confuse your plants and also delay flowering.
Look for signs of preflowers in the nodes (where branches meet the stem) in the medium / top part of the plant.
When plants are early in the vegetative stage, leaves and branches grow opposite to each other. They won’t start showing preflowers yet. Wait a few more days until your plant is sexually mature!
When plants are ready to start growing preflowers and switch to the flowering stage, they start growing alternate leaves and branches sets.
Thanks for reading and commenting!
My Apple fritter took til end of week 2 beginning week 3 to show signs of sex, so I wouldn’t worry. If ur in week 4 and Still no signs of sex, then u might of put lights 12/12 to early. For example let’s say your seeds just germinated and you got a tiny little plant in you’re in a hurry and you think putting the light 12 and 12 will start to flower your plants then you’re wrong the plant won’t start flowering until it’s ready which usually takes about a month in veg state depending on strain. Good luck, happy growing
I hope this is the right place to ask these questions. What is the powder substance that falls when the leaves get moved? The plant is indoors. Is it to late to trim it when it has there little green seed looking things growing? Thank you
Hi! Female Cannabis plants should not have any powder falling off the leaves! A prime suspect for powder on the leaves is “White Powdery Mildew”, a fungal disease that affects Marijuana and may damage your crop. A grow environment with high humidity, poor ventilation or no airflow is ideal for this kind of “mold”. Overwatering and plant crowding or patches of leaves covered in water worsens this situation. If this is the case, clean the leaves with paper towels or cotton and a solution of water + baking soda, Ne water + neem oil, or Hydrogen Peroxide (1 teaspoon of 35% H202 per gallon of water).
If this is your first grow and this doesn’t seem to be the case, check this article to make sure your plant is not a male plant! https://growithjane.com/determining-sex-cannabis-plants-male-female-hermie/
Those “little green seed looking things” may be in fact male preflowers and the powder may be coming from them. In that case, the powder is in fact pollen. Which pollinates female plants and makes seeds.
I hope this helps! Thanks for contacting Grow with Jane!
Is it normal for hybrids to take longer. Flowering than Indicas
Hi Codydog! Yes, it’s normal. Hybrid Cannabis plants may have long or short flowering periods depending on the strain. Most hybrids nowadays show either more Sativa or Indica dominant traits. Indicas have shorter flowering periods than Sativas. For a hybrid Cannabis strain with Sativa dominant traits, flowering periods may be longer and for strains with Indica dominant traits, they may be shorter.
Thanks for reading and commenting!
No just water it like you do. This is my 3rd run with living soil and no flush was needed but I will say that not all living soils make it all the way through with the nutrients they have so if you do add any nutrients flush a week and a half before. All 3 runs were flawless and the taste and smell are way better with living soils
I do not believe so, a freinds dad uses all natural/ worm casings and he dosnt flush for that reason and his flower is ALLWAYS quality
No need to flush an organic grow….nature doesn’t flush, why should you.
Hi Scott, it depends on which organic inputs you add and how is the soil mix managed. Living soils usually do not require flushing but there are many ways of growing “organic”. Lots of brands that offer organic products for growing Cannabis recommend flushing before harvesting, especially when growing in containers. For plants grown directly in the soil and receiving rainfall, there’s usually no need. In fact, many studies suggest that flushing is not required if the plants are not overfertilized in the first place, no matter the fertilizing methods. Many inputs can lead to overfertilization if not applied correctly, even those labeled as “organic”. When this happens, flushing is an easy remedy that helps the root zone regain balance so plants can start absorbing water and nutrients again. The key is to give the plants the right amount of nutrients during the whole cycle. Thanks for reading and commenting, happy growing!
Good morning peoples,I have a quick question. Can I clone flowering outdoor plant without chemical or foreign hormones? Thanks for listening. BTW I’m in NY
Hi Whiteboy, a flowering plant can be cloned but it may be more difficult to root than a vegetative cut. You can do it without chemical hormones but it may be slower to root as well. Aloe vera and kelp extract are used as natural rooting agents by people who don’t want to use chemical hormones. Thanks for reading and commenting, happy cloning!
How should you water and fertilize? Should it be water one day and then fertilize? Or should it be fertilization all the time when you water?
Hello Blu, that depends on the fertilizer, each brand has its own feeding schedule. Some of them need to be applied with almost every watering, some products are meant to be applied once a week, and so on. Check with the manufacturer, most of them have calendars or plans where the concentration of each fertilizer varies every week and with the plant’s stages.
For fertilizers that need to be applied with every watering, you can skip fertilization once a week and watering with water only to avoid nutrient burn and salt buildup.
I hope this helps. Thanks for reading and commenting!
Happy growing!
Hey I’m just starting and I have a beautiful outdoor plant that I have been growing. I topped it several times so it’s a short bushy plant. I’m not sure what kind it is but it’s leaves are all real small even the suckers. Anyways my question is what causes some of my branches that have just started budding to turn yellow and die. Not the very top but a few sucker leave down where it grows new buds die before they even get a chance to produce a leave why. Leaving me with a popcorn bud and a long bare branch underneath.
Hi! First, check if those branches are receiving enough light. Not receiving enough light may cause the leaves to start dying and buds to remain very small. If growing outdoors, bud rot may also be a suspect. Check if there’s any white, gray or brown mold in those small buds and the base of the leaves. Another possibility is that your plant has a nutrient deficiency. Make sure to follow a good nutrient schedule for flowering. The excess of Nitrogen in the soil mix also causes buds to remain very small. Sometimes, it’s better to cut out the lower leaves and branches and let the plant grow their best buds on the top branches.
Thanks for reading and commenting!
unique site! thank you. I wanted to clarify about the circumcision of the lower buds – I’m in the middle of flowering, the plant is healthy and is already showing pretty inflorescences. but I wish they were a little bigger. does it make sense at this stage to cut off the lower small buds to give more energy to the big ones at the top?
I use fertilizers according to the schedule
for flowering stage with high potassium.
Hi Akab! Yes, pruning the lower buds where almost no light reaches will help the plant “concentrate” on the upper buds, where most of the light is absorbed. Remember that leaves are the organs of the plant that absorb light so keep the canopy with some leaves to catch those photons of light and keep the plant growing and functioning. Thanks for reading and commenting, happy growing!
One plant started budding at end of June about when a seed I planted sprouted the sprout is about a foot tall will the budding plant make it start budding already? The budding one is slowly filling in but not crystallized that much it’s weird
Hello Chip! Photoperiodic plants growing outdoors enter the flowering stage when the days grow shorter, usually towards Autumn. In the right conditions, each plant may start the flowering stage as soon as it’s sexually mature, which happens in no less than 3/4 weeks. If your first plant is already budding, make sure to apply nutrients for the flowering stage. If the soil is rich in Nitrogen but poor in P and K (which is very common), buds will be light and small. Some foliar nutrients intended for this stage will also help your plant to start making trichomes.
Your other plant (the smaller one) will continue to grow in the veg stage for a few days before entering the flowering stage. One plant won’t influence the other, both will respond to the photoperiod (days growing shorter). Cannabis plants may start growing buds independently from their size, they may be one foot or 7 ft tall.
I hope this helps, have a nice day and happy growing!
Great article. Thanks for the good info with pictures.
Hi Spike! Thank you so much for your kind words! We have more articles with pictures and illustrations, I hope you enjoy them as well!
Have a nice day and happy growing!