What are the first signs of the cannabis flowering stage?

by Nebula Haze

Week 1-3: Transition to Flowering

When growing marijuana indoors, the flowering stage begins when you change your grow lights to a 12/12 light cycle (12 hours light, 12 hours darkness each day). Getting those 12 hours of uninterrupted darkness each day gives your plant the signal that it’s time to start flowering. In a way, the plant “thinks” winter is coming because the days are getting short. Outdoors, it’s also the days getting shorter that cause a cannabis plant to start making buds in late summer.

Marijuana plants start flowering when nights get long. Indoors this is done by putting grow lights on a timer. Outdoors this happens naturally in late summer..

In order to get a cannabis plant to enter the flowering stage and start making buds, a grower needs to use a timer to put the grow lights on a 12/12 light schedule (12 hours light, 12 hours darkness)

Autoflowering strains of marijuana don’t need special light periods to start flowering. Give these plants 18-24 hours of light a day from seed to harvest and they’ll start flowering naturally after a few weeks from germination. However, their buds look the same and follow the same general timeline. Most auto-flowering strains I’ve grown start getting white hairs/pistils around week 4, though some strains take less or more time.

During the first few weeks after being switched to a 12/12 schedule, your plant will be growing like crazy and rapidly gaining height. In fact, a cannabis plant can (and frequently will) almost double in height after the switch to 12/12. This period of super-fast and often stretchy growth is sometimes referred to as the “flowering stretch.”

At first, you’ll see white fuzzy pistils/hairs at the joints where fan leaves meet the stem. These can appear in the vegetative stage for older plants or soon after 12/12. These are known as “pre-flowers” and are a hint of what’s to come.

Example of wispy white pistils (pre-flowers) on a female cannabis plant

Although your female plants will start sprouting lots of white pistils, they usually won’t start growing “real” buds with substance quite yet. If you’re new to growing marijuana, it’s good to know only female cannabis plants make buds.

If your plant is male, it will start growing distinct pollen sacs and should be removed from the grow room immediately to prevent it from pollinating your female plants and causing ‘seedy’ buds. Learn where to get feminized (all-female) seeds online so you don’t have to worry about male plants.

Remove any plants growing pollen sacs instead of pistils, because they are male and won’t make buds. Plus they can pollinate your female plants and cause them to grow seeds!  What if my plant is growing both pistils and pollen sacs?

These pollen sacs indicate that this cannabis plant is male, and should be removed from the grow room as soon as possible!

During the first few weeks of the flowering stage, you will see bunches of single leaves forming at the tops of your main colas (like in this pic). Soon white pistils will start coming out of the middle of the bunches, and they will become your main buds!

Example of a cannabis plant that has just started flowering, before the budlets form

 

Week 3-4: Budlets Form

The mad stretching of the first few weeks will start to slow down in week 3-4, but your marijuana plant will still be growing upward. At this point, you’ll actually start to see real buds instead of just hairs (I like to call them “budlets” during this stage) and all the pistils will be white and sticking almost straight out.

“Budlets” start forming where buds will be, with white pistils sticking straight out

Cannabis "budlets" or new buds about 3 weeks into the flowering stage. At this point all you can see are a bunch of white pistils sticking straight out where the buds will be.

Another example of a 3 week old cannabis bud (or "budlet") covered in white pistils sticking straight out

Your plant is going to start getting a little picky about the environment and nutrients in week 3-4 so it’s important to keep a close eye on your garden. You need to make sure your plant stays healthy all the way to the end of the flowering stage, and you’ve still got more than a month to go so you don’t want your plant to run into any major health problems now.

Week 4-6: Buds Start Fattening

Your budlets are fattening and soon you will have buds with substance! They will still have nearly all-white pistils sticking straight up in every direction, but the buds themselves will be getting fatter every day.

This cannabis bud is about 5 weeks into the flowering stage. It still has mostly white pistils sticking straight out, but the buds are getting fatter every day

Young marijuana plant in week 4-6, with all white pistils sticking straight out!

Cannabis flowering - about 5 weeks from the initiation of the flowering stage

Example of 6 week old cannabis buds (6 weeks since the beginning of the flowering stage)

Although most of the pistils will probably still be mostly white by the end of week 6, the buds are getting bigger and denser every day!

Cannabis plant in week 6 of the flowering stage - buds are fattening up!

Soon the pistils start darkening and curling in. That’s when you know you’ve reached the second half of the flowering stage. Now it’s just caring for plants and waiting until harvest.

By around week 7-8, your cannabis plants should be really hitting their stride as far as fattening buds!

Learn what marijuana buds look like as they get close to harvest.

 


 

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