Tips For Cannabis Flowering Stage

The flowering stage is the moment we all have been waiting for. For you, as a professional grower, this is the most important part of growing marijuana. Let’s discuss how you can take care of your flowering cannabis and grow the best yield ever.

When your plants switch from the vegetation to the flowering stage, the growth will eventually get slower. When the plants start to develop flowers (so called buds), it is time to treat them differently. This means changes in light and different nutrients for the flowering stage.

While plants have been growing and prospering like crazy in the vegging stage, your plants will now be more prone to problems. Everything that happens from here on out will affect your yield – for better or for worse.

The entire flowering stage will be about 8 weeks and consists of the following stages: transition, first buds, growth of buds, buds ripen and harvest.

The flowering stage of cannabis is when the plants begin to produce sets of flowers. It is also the stage that gardeners make their harvest. The flowering stage is very different from the vegetative stage. During the vegetative stage, the only concern of the plants is to grow bigger and become bushier. During this stage, you can escape with almost any mistake. If your plant gets any damage or infection, you can easily nurse it back to health.

When Does the Flowering Stage Begin?

Despite the name, the flowering stage doesn’t start with the formation of flowers. Flowering occurs a few weeks into the flowering stage. In fact, it doesn’t even correlate to when you induce flowering.

In fact….

The flowering stage begins when the cannabis plant notices a change in light. This is how it knows winter is coming.

Many people mistakenly think that this change means a decrease in light. Actually, the change is measured by an increase in the amount of continuous darkness. Soon after the strain’s threshold of darkness is met, the plant will grow rapidly, gaining height and stretching. Some plants may even double in height during the first two weeks of the flowering stage.

The flowering stages

The cannabis plant develops stems and leaves during the first 1-3 weeks of the flowering stage. However, the growth suddenly changes to the formation of buds during the end of that month. All the necessary parts of the harvest grow during the first few weeks of the flowering stage. Any slight problem in the initial weeks of the stage will harm the overall yield of the plants.

If you plant your cannabis in the outdoors, your plants rely on the season and location of growth for the flowering stage to begin. The flowering of the plant may also depend on the strain of cannabis. Some plants can begin the process right away while others are hesitant since their threshold for darkness is longer. It makes them remain in the vegetative stage for a longer time.

It is, however, very different if you are growing your cannabis indoors. Since you have control over the light, you can quickly help the plants trigger and start flowering by controlling the amount of light in your grow tent.

As the stage begins, the space in between the leaves (internodes) start to decrease, and the growth of the plant slows down. At first, it may look as if the plants have stopped growing. However, there is a lot more growth that takes place during this stage. You should always be keen on the number of nutrients that you use.

Spotting Your First Flowers

Before spotting a marijuana flower, you will still want to support your plants in the growth stage as much as possible. Once the flowers are showing, you want to optimize for light and nutrients. Now you can, and should, switch to nutrients for the flowering stage.

Remember: Only female plants will produce buds. You can make sure to have female plants by using feminized seeds.

In week 3 or 4, the first real buds will show instead of only hairy pistils. The growth of the plant will now slow down a lot - it's important to watch out for the health of your plants at this point. A few dead leaves are normal (ex: if they do not get enough light). You do not want a major disease at this point so it's also important to watch your nutrient levels and observe your plants closely to ensure nothing strange is happening.

Male vs. Female

During this time, both male and female plants will produce flowers. Male flowers are smaller with a yellow, red, purple or pale green color while female flowers will have two hairy, white stigmas.

If you want your cannabis plants to produce potent, THC-rich marijuana, pay attention during this time. This is when you should look for those male plants and remove them from your garden. If they fertilize your females, it will be too late.

But that’s not the only thing to look out for.

In addition to the emergence of flowers, you’ll also notice that the internodes have extended. You may also see some leaves covered in a thin, transparent resin. It will look like your plants are stretching and covered with dew. This resin is a teaser of what’s to come but isn’t worth sampling yet, so don’t get too excited just yet.

I can’t say this enough:

Be patient!

By the end of the first month of the flowering stage, you may notice small clusters forming from the female flowers. These clusters are called buds. They are the same buds that you will eventually harvest (yay!), but they are not quite ready. You’ll need to do a bit more work before it is harvest time.

Growing Autoflowering Strains

If you are growing auto-flowering cannabis strains, you do not need to provide the plants with constant darkness. These plants grow and begin to flower on their own time regardless of whether you are ready for them or not. They are small in size and do not produce high yields. Their vegetative growth stage lasts for 3 to 4 weeks, and they start to flower a month later.

When the flowering stage of your cannabis plants begins, you will notice a couple of changes in your plants. First, your plants cease to grow. You will note that they stop producing more leaves and small white pistils appear and start growing at a fast rate. Additionally, you will see flowers developing from the buds of the plants. During the flowering process, the plants reveal their sex. You will note that the female plants develop pistils while the male plants grow a pollen sack. The male plants grow taller so that they can drop their pollen onto the pistils of the pollen plants.

Nutrients during the start of the flowering stage

You’ve entered the flowering stage, so pay attention.

Your plants will need a different set of nutrients then before. Phosphor and potassium are now the priority, and your plants will need enough of it to keep up with all the rapid changes that occur during this time.

Unfortunately, many growers mistakenly increase these nutrients too rapidly while decreasing the nitrogen too soon. Phosphor and potassium are important, but so is nitrogen. If your plant does not get enough nitrogen, it could develop a deficiency.

Keep in mind,

The flowering stage is hard on marijuana plants. Your plants are going to be very sensitive to both their nutrients and the environment, so keep an eye on them. Pests and diseases could be fatal at this point, and there’s still at least a month to go.

Avoid Overfeeding the Plants

You should not use nutrients during the last weeks of flowering. You may notice the plants shedding off some leaves, especially in the lower regions or those that are shaded. It happens due to the shift in energy as the plants focus on the development of the buds that are on the top of the plant.

However, if the plant leaves start to discolor or shed at a high rate, then it means that you have overfed it with too much fertilizer. You should immediately tend to it to reduce the chances of the problem affecting the buds.

Training during the start of the flowering stage

If you’re growing indoors and plan to train your plants, the first month of the flowering stage is the time to do it.

Why would you do this?

Training helps maximize the space in a grow room, and it can also increase your final yield. During the beginning of the flowering stage, the stems are flexible and can be bent without breaking. However, as the stage continues, they will become woody and unable to be trained.

Second Month of Flowering

During the second month, the plant starts getting ready for harvesting. You will see the plant becoming thicker, and with more buds developing. The transparent resin that formed on the leaves during the first month starts to darken and release a strong odor.

If you are not ready, all these changes happening to the plant may spell some trouble. Your plants will become heavy and require some support. You can set up a trellis system made from strings and wood to offer support to the plants. During this stage, you should ensure that the plants are receiving the required amount of air. Since the plants will be growing wide, some areas will be too close to each other leading to them not getting enough airflow. Without air, the plants can start developing bacteria, molds, and fungal infections that can reduce the number of yields a plant is giving.

Identifying the Sex of Your Plants

You may have already identified and removed the male marijuana plants before the flowering stage began, but that doesn’t mean you are necessarily out of the water.

Watch out for sneaky hermes!

It’s not uncommon for a hermaphrodite to develop during the flowering stage. These plants have male sex organs that will pollinate your precious female plants. So check again during the flowering stage to be certain.

By the second month of flowering, if there are any males in your garden, it’s almost too late. At this point, the female plants will be producing sticky, THC-laden buds, that, if fertilized, the THC loses potency.

If you spot a male flower characterized either by their clearly male pollen sacs, or their yellow banana-like shape, remove the entire bud site to ensure no pollen escapes. Just one could fertilize your entire crop.

Grow Room Conditions

During the flowering stage, indoor cannabis growers need to ensure that the environmental conditions in the grow room is favorable. Since the plants are growing closer to each other, you may need to adjust the temperature and humidity to prevent the plants from getting fungi and diseases. You should ensure the temperature is between 68 – 77 degrees Fahrenheit near the leaves and 68 degrees Fahrenheit at the root level when there is light. When you switch off the lights, you can drop the temperatures to 68 degrees Fahrenheit. When the temperatures are high, the carbon dioxide level should also be high

Ensure that the humidity levels as the flowering stage begin is between 40 to 50 percent. Once you get to the second month, you can drop it to 30 percent or more since you want the buds to produce more resin. You should always ensure that the level of humidity stays lower than 50 percent throughout the whole flowering stage. It may be lower than that of the vegetative stage. However, it is crucial for the success of the farm. The best way to keep control of the levels is by acquiring a good humidity controller if necessary.

Use a carbon-filtered airflow system.

If it hasn't happened yet, your plants now might develop the known marijuana smell. Make sure to use a carbon-filtered airflow system. Your airflow system is important at this point and fresh air needs to be constantly flowing into your grow room. In this phase, your plants will need a lot of CO2 (carbon dioxide) for growth and health.

In weeks 4 to 6 of your cannabis flowering, the buds will get bigger and fatter. Once the flowers are showing as small white pistils (white wispy hairs), your plants will need more phosphor and potassium. Both are important for a good bud formation. The nutrients support flowering and fruiting.

Trim Excess Foliation

Some pros trim their plant leaves at this point (defoliation) so their plants can focus mainly on bud growth. Make sure to leave enough leaves to support your plant’s health! The leaves are fueling the plant’s system and therefore bud growth.

Around weeks 6 to 8, your plant will have stopped vegetative growth completely and only work on the buds. A few leaves might turn brown at the bottom now and this is perfectly normal. Your plants will be sensitive to a lack of nutrients at this point. Watch your pH levels to make sure your plants get all they need.

How do you prune?

Remove leaves that will not thrive

It’s okay to prune any of the buds that are in the shadows

Do not prune leaves that are in the shadows but are still thriving

You shouldn’t prune too many leaves because your plant isn’t going to grow many of those leaves back. Plus, you need them to absorb light and keep flowers developing.

Avoid Light Burn

Even though your plants love your powerful grow lights, make sure they do not get burned by high levels of light and heat. If you're using a grow tent, be sure it has enough height for the lights to be at least 12-36 inches above the top of your plants' canopy. If you're using higher wattage lamps (1000W or similar), you should be at the top end of that range, and for lower wattage lamps (250W or similar) you can be at the low end of that range, but make sure you always have at least 12 inches.

A final, supremely important thing to note about lighting during the flowering stage: once you start switching to the flowering light cycles – never go back. Never expose your plants to light in the dark phase of the day. You do not want to confuse your plants or make them switch back to the vegetation phase. This could dramatically impact your yield. It is the un-interrupted darkness that leads your plants to flower. Make sure this darkness is definite - not one minute of light in the night! Use a programmable timer to make sure you don't forget when you need to turn your lights on or off, and be sure to test your settings and confirm they're correct before trusting it on your precious cannabis plants.

Hardly any flowering cannabis will be ready for harvesting before week 8. You will be watching your plants closely at this point, treat them like a lady! Cater to all their needs. It also may be helpful to consider flushing them out using plain water for a few days before harvest. Between week 8 and 10, they should be ready for harvest depending on the strains. The intensity of the marijuana smell could be a good indicator. Your plants might start turning yellow at this point, which is what the plants normally do when they finish up the flowering stage. Do not raise your nutrient levels at this point. Your buds should be big and fat at this point... which means...

You made it! Enjoy your harvest!