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Flowering Stage

Flowering Stage

The flowering stage doesn’t correlate perfectly to the point when you induce flowering in your plants. Actually, cannabis plants will develop flower structures within the first couple weeks of this stage.

The internodes will decrease and the plant will continue to grow upwards (sometimes somewhat more slowly than it was growing before). However, there is a still a lot of growth to be completed in the beginning of the flowering phase of the cannabis life cycle. It’s important to keep this in mind when thinking about how to properly feed your plant!

When your plant begins to mature and develop flowers (yay, buds!) you have to treat it differently. We’ll help you through this exciting milestone with an analysis of how to handle the mature phase of your cannabis plant’s growth.

Flowering fertilizers

Many new growers switch their nutrient ratios too early. It’s easy to to do, but remember your plant is still growing at the very beginning of the flowering phase. While it’s true that the plant will need more phosphor and potassium, it’s still growing for a few more weeks! So it still needs nitrogen.

If you stop giving the plant enough nitrogen at this crucial stage, it could develop a deficiency. Right when you’re nearing the finish line, the plant will begin to yellow and its health will decline. Don’t alter your nutrient solutions until the plant shows very clear signs of flowering. You should be able to see stamens and pistils clearly when you change over.

Start of flowering stage

Start of flowering stage - Day 45

During the first two weeks of the flowering stage your cannabis plant gets taller and the spaces between the leaves (internodes) will begin to shorten. Shortly after this, you will begin to see the first pistils appearing. You’ll know the flowering phase has started in earnest when you see a lot of these.

Pruning buds

A little over a week after that, the marijuana plant will stabilize its growth patterns. You can prune away all the buds that are in shadows since they won’t be developing the compact flowers you’re looking for.

At this point, you want to maximize the light and nutrients that will be focused towards developing those precious buds. When you’re pruning, try not to cut off any of the leaves.

Tip: make sure to download my free Grow Bible for more information about flowering stage

It can be tempting to cut off some of the large leaves which shadow the flowers. DON’T DO IT. Your plant needs those big strong leaves to absorb light and keep the flowers developing. Only cut off leaves if they are dead or otherwise compromised.

Temperature, humidity and nutrients

When your plant reaches the flowering stage of growth, you’ll want to modify the environment accordingly. If you aren’t already using them, you’ll want to switch over to sodium vapor lamps: they emit the spectrum of light that is ideal for flowering cannabis.

sodium vapor lamp flowering stage

Use a sodium vapor lamp during flowering stage

You’ll be changing the day/night cycles of light exposure as well, shortening the amount of time that the plant receives light during. Many growers favor equal ratios of light and darkness in a 12:12 hour cycle throughout the day.

Once you start this process, make sure you don’t interrupt it! You don’t want to confuse your plant by letting it be exposed to any light during the dark periods of the cycle. Not even once. This sort of illumination interruption can easily cause the plant to change back to a growing cycle, and you could inhibit your potential yield.

Flowering stage temperature and humidity

Flowering stage temperature and humidity

You’ll want the air temperature to change between the light and dark cycles as well. When the plant is exposed to light, the temperature should be hovering near 68ºF and 77ºF (20ºC and 25ºC) near the foliage and 68ºF (18ºC) at the roots. Remember that higher temperatures will require accordingly higher levels of carbon dioxide. When your plant is in the dark, you can let the temperature drop down to about 68ºF (18 degrees Celsius).

Keep the humidity at a steady 70%. Keeping this stable will help you avoid any pest issues that could arise during the flowering phase. Now is also the time to switch over to a flowering nutrient solution. As stated above, just make sure you don’t switch over too early.

First flowers

After several weeks of the 12:12 hour day/night cycle, the marijuana plant will stop growing and start flowering. The initial flowers will appear on the buds. At this point, the plant shouldn’t be producing any leaves at all, and you’ll see small white pistils developing rapidly and multiplying on the surface of the plant.

First flowers cannabis plant

First flowers showing
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Some of the leaves will begin to be covered in a thin, transparent resin. This will happen most closest to the flowers. At this point, you can switch over to your flowering nutrient solution. Your plant requires higher levels of phosphor and potassium during this phase to keep up with the change in growth.

Sometimes new growers can be tempted by the buds and the resin being formed. Whatever, you do, don’t hack up your plant to try and ‘taste’ it. It’s still not fully developed, and you won’t learn anything, except possibly what a small yield you get when you cut apart your immature plant before it’s fully developed. The cannabis plant needs time to mature before you harvest.

Flower expansion

About a month after the flowering stage begins, you’ll begin to notice more changes that signify the beginning of plant maturity. The buds themselves will expand and distend: that’s normal. It’s good. Your plants will also grow outwards, widening and getting thicker. The number of calyces on your plant will keep rising. The transparent resin you noticed early will darken and develop a strong odor. If you’ve got a good plant, there will be lots of it.

Flower expansion

Flower expansion

Because of the expansion, the flowers will grow closer and closer together. At this point, the plant will be bearing a lot of weight and will almost certainly require some support. You can create a trellis system with string or wood, or you can use a metal spring system. The metal spring systems are nice because they will actually adjust the weight of the plant as it matures.

Once the marijuana plants have grown extremely closely together, you’ll likely want to lower the humidity a little bit to minimize the potential for mold, bacterial, or fungal development in those spots. It’s hard for air to circulate through the tiny gaps.

Fully mature flowers

Maturity is probably the most crucial phase of development in the cannabis life cycle. At this point, you're just days away from being able to harvest and process the yield you’ve been working on over the previous months. The time you harvest will have a huge effect on the end product.

Fully mature flowers

Fully mature flowers
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You’ll notice that the calyces and pistils start to turn red as the plant finishes maturing. The resin will continue to accumulate, getting stickier and heavier with every passing day. The flowers will draw together and close up any remaining space.

This is the point at which your plants will develop a powerful odor. The best way to deal with the odor is the utilization of carbon filters. Just trying to mask it is unlikely to be effective, and will probably just complicate the problem.

When to stop fertilizing

You’ll want to stop fertilizing your marijuana plants about two weeks before the flowering stage finishes. This will allow your irrigation and watering to rinse minerals and nutrients out of the plant, making it safe and enjoyable for use.

Rock wool, soil, and coconut fiber require two weeks, but if you’re using clay pellets, even a week of water rinsing will clean out the substrate. This cleaning process is very important if you want to get a quality product in the end; otherwise there will be a lot of unused minerals drifting around the plant’s insides.

stop fertilizing

Stop fertilizing - week 7

When at least half of the pistils on your cannabis plant have turned red, you are ready to harvest. The resin should be thick, and easily visible to the naked eye. The plant should be very heavy with buds, and some of the leaves might be turning yellow.

As the leaves turn yellow, you can remove them from the plant. They turn yellow at the end because energy is being devoted to the flowering parts of the plant. Just make sure you don’t remove any green leaves— those are still producing valuable energy!

Tip: read everything about the seedling stage or vegetative stage

Thanks for reading. Please leave comments or questions below and don't forget to download my free grow bible


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Comment Section

58 thoughts on “Flowering Stage

By terry208 on 16 May 2015

Everyone says that indoor plants must remain in total darkness during the dark phase, but outdoor plants are never in total darkness, can you explain the difference?

By bayou critter on 23 August 2015

whats up peeps well I get really good results from a giant flouresent good heavy bud but can someone tell me
if fox farm is a good fertilizer solution anyway let u all know seems like I was having betterresults with the earth juice so guys tell me wht ya think growing in dirt

By SparkyPipes on 22 August 2017

I prefer Fox Farms potting soil it's excellent if used dirt for your medium ingrowing. And I really like the Technafloral line. It really helps you keep your pH the same every time you feed your plants. Also, you can add other nutrients to Technafloral to enhance size and resin production, i.e. Big Bud, Bud Factor X, Bud Igniter, etc. Best of Luck! I started with the Fox Farms series in fertilizers. It did a good job but I found the Technafloral method gave me three times larger buds and resin production. Just remember to feed, water, water. And if you continue that rotation your plants will be well flushed and there will be no build up of nutrients.

By Joe on 22 May 2018

I have great success with Earth Juice Seablast indoor in soil. Oily Cann for cal/mag.

By Bry77 on 29 May 2016

Marijuanna is only sensitive to Red and Blue spectra of light. The light at night(moon light) is green and does not affect your plant or so i am lead to believe...

By Leigh Lowe on 5 April 2017


By john callahan on 10 June 2015

are led lights good or bad?

By #purplehaze on 12 February 2018

LED lights are super great for planting. 1000 watts is perfect! Quiet, and has built in fan to keep heat low. The lumens are what 1000 wats equals, whatever that is. And molasses water, keeps them dark green and strong. Good carb for soil by increasing microbes,which feed the roots!

By latewood on 15 June 2015

The question on LED is off topic here. It is a matter of choice. I use HID lamps. Please post lighting LED question in our support forum in order to get more efficient responses, from LED growers. 🙂

By Jesse on 2 April 2016

I use 1000w Led with my 1000w HID now and it only saves electric and not as intense. I have done Led harvest, but didn't knowtice much of a difference. Only thing different is how dense it was, you dense buds with HID over LED

By latewood on 15 June 2015

Terry, I do not totaqlly agree that Outdoor plants are never in darkness; However, I have not got an answer for you; To be honest. If you are talking about the Moon; I cannot come up with a good theory, as of yet.
I will tell you though; If you do not grow your induced indoor plants in total darkness, you could develop hermaphroditic plants.

By PHIL420 on 17 June 2015

Thanks man for all of the correct input you've been more helpful then anyone else & the info is rt. on the money,Peace brother n be well Medicaided!

By latewood on 25 August 2015

bayou critter,
I have trouble understanding 1/2 of your post, but as far as nutrient lines. Use what you feel comfortable with. Happy growing.

By k capoferri on 27 August 2015

hi ILGM, i've been reading your articles on every aspect of growing your seeds. you say to stop using nitrogen near end of bloom stage. the manufacturer of my hydroponic grow box says the product sent with the grow box can be used from start to finish. the product "Moon Dust" is 19-8-13. i'm confused. can you please advise. this is my first grow. thanks. kc

By sean on 5 January 2017

I've used moondust several times, its like Lakewood stated, last two weeks stop and flush, or when you get to flowering stage use less or get a good bloom nutrient. Ive used 1/4 tsp for a complete grow with dust, last 12 days flush, perfect ww autos. 1/4 tsp from start in one gallon hydro, perfect. I'm trying what Robert recommends next. I think the seeds with nutrients package he offers, looks to be a no brainer! Go for it. Sd

By Muhafid on 27 August 2015

I am usually to runinng a blog and i really admire your content. The article has really peaks my interest. I'm going to bookmark your site and preserve checking for brand spanking new information.

By Redneckpotsmoker on 30 August 2015

I have a plant first time growing growning its on 55th day and about 3 foot tall ever since I sprouted it its been going outside at 8 in morning I bring it in at dark and it stays in my closet till next morning should I keep doing this or do I start shorting its light time now have pic can send of it to

By latewood on 2 September 2015

k capoferri,
When you see the phrase, "from start to finish", this means that you can use this nutrient throughout the entire grow. This has nothing to do with the final "flush"; Or, what you read as stopping the application of nutrients. We stop applying nutrients the last 2 weeks of the grow period, in order to allow the plant to use up stored nutrients, resulting in better tasting Marijuana. 🙂 Hope this helps you . Peace ")

By latewood on 2 September 2015

Thank you for the kind comments. We are glad you have found use for the information provided in this Blog. Feel free to join our support forum in order to find many informed growers that are always willing to help a brother out! 🙂

By sean on 5 January 2017

Sorry latewood, I spelled your name wrong!

By latewood on 2 September 2015

This is really hard to answer. If you have been keeping it outside only for the daylight hours; You are already on a short photo period. The only reason to reduce the photo period, would be to induce flowering. This should happen naturally outside, due to the fact that days are getting shorter, and Autumn is approaching fast. 🙂

By Pat on 17 February 2016

I have a question. I am about to try my first scrog grow and I don't have a clear idea of what most growers use and the method of getting rid of runoff. Maybe someone can point me in the direction of a video on how set up a scrog grow. I will appreciate any advice at all. Happy growing. Keep it green.

By mamali on 1 May 2016

hello my plant in flowering stage day40 in soil and reason travel and light off problem spider meet spray abamactin i dont know this problem badeffect to myplant?

By latewood.ILGM on 3 May 2016

I have to apologize. I cannot make any sense out of your post. Please try again and separate your thoughts. Help me help you. Thanks 🙂

By Kay on 12 September 2016

Hi, thanks for your blog! It is truly a fountain of information that I can understand. I'm a new-bee with a new blog.l
Also I'm a 71 year old retired married great grand-mom, who is dabbling in just a couple of plants for personal use. I planted my first seeds. Not sure how they will be, believe me it wasn't done by the book. Also I have been dabbling with the thought of investment also. That's going to be more tricky than growing. Thank You

By Roy ILGM on 13 September 2016

Most welcome Kay and happy growing!

By latewood_ILGM on 5 January 2017


You should join our forum. We have many mature, retired professionals and med patients who I think you will find interesting. 🙂 And; We are always willing to help out and share growing advice to all who come. 🙂

Peace, lw

By latewood_ILGM on 5 January 2017


I am sorry. I cannot decipher what you are trying to ask.

Vreg stage comes 1st. You should not be cropping plants until you have experience to do so. Flower stage comes 6-10 weeks after planting seed/.

You have much to figure out. You should join our support forum, and we will help you grow successfully, from start to finish.

Happy growing 🙂

By Katie on 5 January 2017

I f using hydrotank. And on 1st generative period I on 7th day can I go bk as I Think I shudnt be on flower stage. As I have no white flower just kinda looked like it. I'm scared as used fruitful feeds I cropped away its growing still I'm flushing tank once wk and feedback twice wk

By latewood_ILGM on 5 January 2017


See above reply. 🙂

By Alex on 26 April 2017

So I am first time grower and on the 6th week of flowering and I have several questions:

1. I am growing Gold Leaf and 1 plant has started getting golden all around the plant, like leaves and pistils are a light golden color. Should I stop using nutes and flush or wait until the end of 6th week, this Saturday?
2. My other 2 flowers are bigger than the one mention above but had a calcium deficiency last week, got some cal-mag fertilizer that seemed to have solved the problem. Do I extend the fertilizer period to make up for the problem or flush this Saturday and stop using nutes all together?

The nutes i am using are:
Tiger Bloom
Overrdrive-advanced nutients

By Robert on 2 July 2017

Nevada is very hot will need to a.c. my green house

By Mike on 29 July 2017

Hi I have a 40 day old low flyer it's got 6 fan leaves and it appears to be starting the flowering stage it's about 8 inches tall is this normal

By latewood_ILGM on 3 August 2017


We would need to see a picture. Not knowing the genetics or grow methods severely limits our ability to give you an informed answer.

Try joining our ILGM support forum and we will be glad to help you find the info you seek. 🙂

Happy growing

By Lee on 25 January 2018

Thanks for your post on growing! I'm sure you will be a lot of help to a new grower, because I'm new at it!

By Dick on 23 February 2018

You don't EVER want to have 70% humidity! That's terrible advice! WTF!?

By latewood_ILGM on 27 February 2018


Old school growing, I agree never use that high RH in flower. However; New science and using high power LED and C02 and also a higher temperature is being used by some with success. I would never probably use 70% but, science is evolving and a lot of what we used to teah is more of a guyidline now. Happy growing.

However; IN general, I agree with you after reading the article, and I will forward this as a typo to the editor. Thanks.

By chachi on 12 May 2018

I'm using a 450w LED lighting system with a flowering switch, indoor grow, WW auto seeds. I had 1 plant that germinated and is 6 weeks old using 20hr on/4hr off. It's roughly 2 ft tall but bushy.
What should I look for to determine "when" I should flick that flowering switch ON ??

By latewood_ILGM on 13 June 2018


You have to decide on how big you want the plant at finish. Plants stretch 2-3 times the size it is when flowering is induced (throwing the switch). If you have limited space you want to flower with at least 2/3 of entire space between plant and lights.remaining. In general; Plants are in veg for 1-2 months then flowered if adequate space is available.

Happy growing 🙂

By RoyC on 12 June 2018

re ask
Everyone says that indoor plants must remain in total darkness during the dark phase, but outdoor plants are never in total darkness, can you explain the difference?

By Daniel on 22 June 2018

I use canna classic flores a+b for grow and bloom. Usally veg only goes for a month anyway. It has prevented cal mag deficiency from my grow. Last crop I didn't get a single yellow leaf.

By wyatt on 27 June 2018

Been growing since the70s and have learned alot over the years. At one point I used miracle grow all the way thru till I cut my plants for drying. Now I have found a better way. For veggie stage I mix in a gallon of water 1 quarter tsp amonia, 1 half tsp baking soda and 1 tbs Epsom salt. You will not believe the results. And its super cheap! For the flowering plants I use fish emulsion one tbs per gallon of water. Results are amazing! For the first time i'm using led full spectrum. At first I didn't think it would work. Not enough heat. I was very wrong! It seems less heat helps my plants and I don't have to worry ABOUT how close my light is to the plant. It's AWESOME! Kudjos to whoever come up with the led plant light!

By Craig on 27 June 2018

I’m an indoor grower and I’ve perched all my seeds from ILGM , I’ve got 8 different varieties and I’m going to start 6 plants at the end of July . I’ve planted 4 last year all from ILGM and all came to full flowering and were fantastic . Now I’m going for the 6 plants I’m allowed in Oregon , I will keep you all posted . And a big thank you to ILGM your seed come vary quickly and I’ve got them in my refrigerator cool and dark till I use them . Thank you all again .

By Greg on 28 June 2018

What do you think about araroa 707

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