The vegetative stage, during which the plant’s leaves and branches grow, is followed by the flowering phase. Generally, this stage is more tricky and more sensitive, where the room for the error is minimum. The cannabis plants grow very differently in the flowering stage, and any mistake can cost you lower yields.
If you are a new grower, this stage can make you feel overwhelmed. But the knowledge of the fundamentals along with practice can make things easier for you over time.
You can better take care of your plants by focusing on each phase of the flowering stage and having knowledge of what to expect during each period.
Since flowering is a critical stage of marijuana’s life cycle, this guide would give you essential tips and tricks, enabling you to better deal with the issues associated with this phase.
- 1 Watching out the flowering cycle
- 2 Transition to flowering
- 3 Stages of the flowering
- 4 How to induce the flowering stage?
- 5 Auto-flowering strains
- 6 Spotting the first flowers
- 7 Male vs. female
- 8 What else is critical at this stage?
- 9 Nutrient requirements of plants during the flowering stage
- 10 Maintain the health of plants during flowering
- 11 Use correct nutrients
- 12 Avoid overfeeding
- 13 Train your plants for the flowering stage
- 14 The second month of flowering
- 15 Provide support to your plants
- 16 Maintain the airflow
- 17 Determining the sex of your plants
- 18 Grow room environment
- 19 Likely problems
- 20 Prune your plants
- 21 Monitor pH levels
- 22 Avoid nutrient burn
- 23 The final weeks of flowering
- 24 Preparing for the harvest
- 25 Final thoughts
Watching out the flowering cycle
It is crucial to know the changes your plants go through during the flowering stage; this guide would walk you through each week of the cannabis plant buds forming phase.
Transition to flowering
With a change in light, cannabis plants initiate the flowering stage. That is their way of knowing winter is coming. A change in the lighting does not mean a decrease in light, as many people believe it. Change, here, refers to a continuous period of darkness.
As soon as the strain’s threshold level of darkness reaches, the plants start rapidly growing, gaining height and stretch. Some plants even may gain a double-height during the first two weeks of the flowering.
Stages of the flowering
During the first 1-3 weeks of the flowering stage, plants will grow new stems and leaves. By the end of the flowering month, that growth sets to support bud formation. The beginning of the flowering stage triggers the growth of all parts of the plant necessary for bud development.
It is critical to note that any problems during that period can severely affect the yield of your plants.
With the flowering stage setting in, your plants’ growth slows down, and you note a decrease in internodes (spaces between the leaves). While the plants continue to grow upward, you may feel like they stopped growing.
Since a lot of growth occurs during those first weeks, you need to stay alert and pay attention to the nutritional needs of your plants.
How to induce the flowering stage?
For the plants growing outdoors, the flowering stage will occur naturally. Sometimes you prefer to trigger a flowering stage for some reason.
Why trigger the flowering stage?
- You want your plants to flower sooner.
- You like the plants to finish growing.
- Early harvesting seems the most appropriate option.
If that is the case, all you need is to give 12 hours of darkness every day to tell your plants. A blackout sheet over your plants can do the trick to induce your plants into flowering.
Growing indoors is different, and you need to deal with it differently.
In an indoor setup, you grow plants under artificial sunlight provided using grow lights. Therefore, the flowering stage will not begin unless you change the lighting schedule to initiate it.
- A light cycle consisting of 12 hours of lighting and 12 hours of darkness can tell cannabis plants it is the time to flowering.
- By switching the grow lights to a 12/12 light cycle, indoor cannabis farmers can trigger a flowering stage.
- In other words, you provide your plants 12 hours of lighting, followed by 12 hours of darkness within 24 hours.
- The uninterrupted 12 hours long darkness gives your plants a signal, and they initiate flowering. The plant decodes this signal as winter is coming, and days are getting short.
For the outside grown plants, the flowering depends upon the time of the year and your location. Depending upon cannabis strains, some may go into flowering earlier, while other cannabis strains may take longer due to extra-long darkness threshold.
Growers alert: Cannabis plants need 12 hours of uninterrupted darkness to initiate flowering. If the plant gets light during the darkness period, even as short as one minute, it will not develop buds. Make sure your plants get 12 hours of darkness consistently.
By starting the flowering at a predesignated time, auto-flowering strains set an exception to the above-described process. In other words, they don’t need an uninterrupted darkness period.
There is a bit more you need to know about the auto-flowering strains.
- These strains grow faster.
- The vegetative stage of auto-flowering marijuana strains typically lasts for 3-4 weeks.
- The flowering stage begins after one month of growth.
Spotting the first flowers
With the beginning of the flowering stage, you may notice some of the crucial changes in your plants. After a couple of weeks, your plants stop growing and begin flowering.
You will observe small white pistils begin to appear rapidly all along the surface of the plants, while plants are no longer producing leaves.
You will also notice flowers sprouting on the buds.
Growers alert: Your plants require meticulous attention at this point. Your plants reveal their sexual orientation.
You will notice that the male plants tend to develop pollen sacks, while females begin to grow pistils. The male plants continue to grow taller while the females remain short heighted. That allows males to drop their pollen onto the females’ postils.
Male vs. female
Both male and female plants produce flowers during this time. They differ in appearance, structure, and colors. Male flowers tend to be smaller with a yellow, red, purple, or pale green color. On the other hand, female flowers consist of two hairy, white stigmas.
If you like your cannabis plants to produce THC-rich yield, it is time you need to pay the most attention. Probably, it is time you need to spot the male plants and remove them from your cultivation area.
What else is critical at this stage?
In addition to flowers sprouting on the plants, you will notice that internodes are extending. You may also come across leaves covered in a thin, transparent resin. And it would look like your plants are covered in dew. The resin is a sign of yield, but for the real deal, you have to wait a bit longer.
You must be very patient at that time.
As the first month of the flowering stage tends to end, you may notice, little clusters are appearing from female flowers. These clusters are buds that you eventually want to harvest.
However, your job is incomplete yet, and you need to do a bit more work before starting harvesting.
Nutrient requirements of plants during the flowering stage
As the flowering stage approaches, you need to pay the utmost attention to the nutrient requirements of your cannabis plants.
During this time, your plants need different nutrients than before. An adequate supply of phosphor and potassium ensures your plants are keeping up with the rapid changes occurring during this time.
Many growers tend to increase these nutrients too rapidly while decreasing the nitrogen too soon. Avoid committing this mistake. Phosphor and potassium are vital, but nitrogen is essential as well. An inadequate supply of nitrogen would leave your plants deficient.
The flowering stage is a very critical period. Your plants can get sensitive to environmental changes such as nutrients and light.
Pests and diseases at this point can ruin your dream of harvesting a good yield. At least you are a month away before you can reap the fruits of your indoor cannabis farming.
Maintain the health of plants during flowering
Your plants need to be healthy, green, and lush when they are forming buds. Otherwise, your yield is likely to suffer. Pay attention to signs of discoloration such as yellowing leaves from nitrogen deficiency. Similarly, other signs of stress need to be addressed adequately before the start of the flowering stage.
The growers who use nutrients need to use flowering formula during the first month of flowering. And it is good to continue with it until you notice obvious signs of flowering. The flowering symptoms manifest in the form of stamens and pistils.
Use correct nutrients
Vegetative formulas ensure that your plants have all nutrients essential to flower successfully. It is crucial to keep using vegetative formula unless you find plants are flowering for sure.
On the other hand, flowering formulas meet the high demands of plants during flowering. Once you reach the flowering stage, only use them for the first month.
During the final weeks of flowering, stop feeding your plants.
In case you find a few leaves falling off, no need to be worried. It is normal, but only in shaded parts of the plant such as lower leaves. These leaves are no more good since plant energy is diverted to the top and used for the formation of buds.
However, if there are discolored leaves and they are falling off rapidly, possibly, you are giving your plants excessive fertilizer. Alternatively, your plants may have a disease that needs to be taken care of immediately.
Train your plants for the flowering stage
If you are an indoor cannabis grower and want to train your plants, the first month of flowering is the most appropriate time to accomplish this job.
Before proceeding ahead, it is logical to ask. Why would we do this?
Training allows space optimization of your grow room. It can potentially impact your final yield.
During the beginning of the flowering stage, the stems are soft and flexible and, therefore, can easily be bent without breaking.
However, with the progress of the stage, the plants become woody and unable to be trained.
The technique of gently bending stems refers to as low-stress training. That involves the bending of plant stems and the training plants to grow outward instead of just up. You may reap the following advantages by practicing low-stress training.
- By providing a flat, even canopy, you expose more of your plants to the light source.
- Low-stress training can increase your yield by up to 40%.
- It allows you to optimize the space of your grow room.
Only train your cannabis plants during the first month of flowering when the plant is stretching, and stems are flexible.
The second month of flowering
As the flowering cycle progresses, you will notice more leaves, branches, and buds appear on your cannabis plants. And they spread out and become thicker. At this point, the bottom leaves tend to grow out further than the top making the plant look like a Christmas tree.
It shows your plants are healthy and growing mature.
What happens during this time?
During the second month, cannabis plants begin to look like they are ready for harvesting. You will notice the number of calyces on the plants continues to rise.
The transparent resin from the first month starts darkening and developing a strong odor. The buds expand and extend.
Provide support to your plants
All this growth can cause problems, especially for the new growers. Your plant may get too heavy to stand upright. If this is the case with your plants as well, provide support to them.
What can provide support to your plants?
You may use a trellis system made of wood or string. Alternatively, you can use a metal spring that adjusts the weight of the plant as it matures.
What else you need to look out?
You may find some of the bottom leaves turning yellow. It happens since plants channel their energy to leaves and buds that are getting direct light. However, most of the plant is green at this point.
Maintain the airflow
Proper air circulation is crucial for marijuana plants, in particular when you are growing indoors. Make sure your plants receive plenty of airflow during this time.
Cannabis plants grow wide during this stage and may get closer to each other. An inadequate airflow may make it easier for mold, bacteria, and fungal infections to ruin your plants.
Determining the sex of your plants
You may have early identified and remove the male plants before the beginning of the flowering stage. But stay alert.
It is common to develop hermaphrodite during the flowering stage. Such plants can have male sex organs and can pollinate the female plants. Therefore, being attentive and alert always help during that time.
If male plants are part of your indoor garden by the end of the second flowering month, it’s almost too late. You can spot them from their pollen sacks or their yellow banana-like shape. In case you find a male plant, remove the entire bud site to ensure no pollen escapes.
You will notice female plants producing sticky, THC-laden buds. If they fertilized, they could make your buds lose the potency. Just one is sufficient to fertilize the entire crop.
Why is that important?
Unfertilized buds, called sinsemilla, are highly valued by many marijuana users. Since fertilized buds stop channeling their resources to grow buds, they grow seeds instead.
By directing its energy to growth instead of reproduction, an unfertilized female plant can produce more THC than any other variety of the plant.
Male plants can also produce THC but in much lower quantity. Therefore, you can get the most potent buds by focusing on the sex of your plants and keep females unfertilized.
Grow room environment
Indoor growers have to deal with a unique set of challenges once the flowering stage is underway. At this point, marijuana plants grow larger and come too close to each other. They need different growing conditions to stay healthy.
You can encourage growth and prevent diseases by adjusting air, temperature, and humidity in your grow room. When lights are on, keep the temperature between 68֯F and 77֯F (20֯C and 25 ֯C) near the foliage and 68֯F (18֯C) at the roots.
Mind, higher temperatures are associated with higher levels of carbon dioxide intake. In the darkness, when lights are off, you can maintain a lower temperature, such as 68֯F (18֯C).
With the beginning of the flowering stage, you can lower the humidity and maintain it between 40-50%. During the second month, a further drop in the humidity level to 30% can force the buds to produce more resin.
It is critical to note that the humidity level during the flowering stage needs to be lower than the level required in the vegetative phase. Adequate humidity control is essential to the successful yielding of your indoor plants.
The humidity needs to remain below 50% during the flowering stage, so use a dehumidifier if necessary.
During the flowering stage, you need to pay attention to the emergence of two likely problems, in particular, when you are a new grower.
- First, we talked earlier about the yellow leaves. A few are fine, but too many in your indoor plants can be a sign of an alarming problem. Excessive yellow leaves may point to a problem caused by the inadequate level of nutrients or light. The good news is both are easy to address during the flowering stage.
- Second, keep an eye on foxtailing. It refers to a new bud called a spire, sprouts along the side of an old bud. It is not normal and is bad for the plant yield.
The emergence of foxtailing indicates that your plants are not getting proper heat or light. If left unaddressed, conditions like this can discolor your buds and evaporate THC.
Prune your plants
Consider the pruning of your plants during the second month of the flowering. Once you have finished low-stress training, and your marijuana plants have stabilized their growth patterns, cut them to an appropriate size.
Some growers go for the super cropping at this point, but it may prove damaging since many of your plants do not have sufficient time to recover from the stress.
Pruning is not necessary, but if done well, it can optimize your plants’ growth. The correct pruning saves the plant’s energy and directs most of the nutrients and light to the most promising buds of the plants.
How to do pruning?
You can optimize your plants’ growth through correct pruning by taking care of the following issues.
- Only remove leaves that are not thriving.
- It is ok to prune any of the buds that are in shadow.
- Do not prune leaves that are thriving even when they are in a shadow.
- Avoid pruning too many leaves since your plant is not going to growing many of them back. And they are required to absorb light to keep buds growing.
It is alright to remove the discoloring leaves. They turn yellow since plants divert energy to their flowering parts. Make sure you do not remove any green leaves as they are still producing energy for the plant.
Is defoliation useful?
Some growers resort to defoliation and remove some of the leaves off the plants exposing buds to more light. However, this practice is not without risks.
The leaves provide energy that helps plants to grow. Even when a leave blocks the light and prevents it from reaching the flowers, chances are it is still doing good to the plant.
A healthy leaf contributes to the health and growth of a plant, so unless a cannabis plant leaf does not exhibit the signs of dying, leave it alone and let it do its job.
Monitor pH levels
The marijuana plants become very sensitive during the flowering time, and it is easier to overlook their pH level. As a result, cannabis plants can suffer from improper pH levels, specifically in the root area. The incorrect pH levels can prove fatal to your indoor plants.
The signs of wrong pH levels manifest in wrinkled or curled leaves, and it is common to mistake them as nutrient deficiency. Therefore, it is critical to maintaining the pH levels, whether you are growing indoors or outdoors.
The following tips can help you to check and properly maintain the required pH levels.
- Always start checking the pH level near the roots.
- The soil should have a pH level between 6.0 and 7.0. In hydroponic systems, it should be around 5.5 and 6.5.
- Never overlook pH testing, in particular during the flowering stage.
- pH testing kits are conveniently available.
- Testing is easy and inexpensive.
Avoid nutrient burn
As mentioned earlier, flowering is a sensitive stage of the cannabis plant growth cycle. Any errors at this point can impact your plants’ health. It is not just pH you need to take care of; overfeeding of the plants can also inflict damage to your plants.
Whether you are using organic compost or store-bought nutrients, you need to exercise the ultimate care to prevent overfeeding the plants.
The following listed information may help you to understand what nutrient burn is and how to ward it off.
- Overfeeding may cause the tips of leaves to appear burnt. In the beginning phase of the flowering, it is ok.
- Too many nutrients not only burn your plants but also affect the taste of your yield.
- Nutrient burn during the last few weeks can be fatal since there is not enough time to repair the damage.
- When burn starts to appear in the fingers of the leaves, it shows you have gone too far.
Limit your nutrient use to only when your plants clearly show the nutrient deficiency. We also recommend checking pH to make sure the issue is not related to pH instead of nutrients.
The final weeks of flowering
Since there is no fixed number of weeks for flowering, you must be able to recognize the signs of flowering. Generally, the flowering process takes place over 1 to 2 months, but you may realize that some strain may go for an additional two weeks period.
When signs of maturity appear, it shows you are just days away from being able to harvest your yield.
What are the signs of maturity?
- The calyces and pistils swell up and start to turn red.
- The resin continues to accumulate and become sticky, heavy with every passing day.
- You will see flowers drawing together and closing up any remaining space.
- A considerable increase in THC production happens on or around buds during the final weeks. The stringent odor of THC acts as a bug and pest repellant and keeps them away from flowering plants.
Preparing for the harvest
Please remember to flush out your plants’ growing medium 1-2 weeks before the harvest. It is better for your health as well as the quality of your buds.
This process allows plants to irrigate and rinse mineral and nutrient out. It ensures your yield is safe and enjoyable to you.
At this point, you may cut off all the supply of nutrients to your plants so that none of the chemicals remain in the final consumable product.
Generally, cleaning needs to be completed two weeks before the end of the flowering stage, but it could vary depending upon the medium used.
For example, rock wool, soil, and coconut fiber require two weeks, while in case you are using clay pellets, even a week of water rinsing will clean out the substrate.
Use neutralized water, that is with a balanced pH level. Do not forget to test the water before the irrigation of your plants.
The use of neutralized water can also help with if there is any pH imbalance in the soil or if there is a nutrient toxicity issue.
When to harvest?
The timing of your harvest can leave an enormous impact on the quality of your end product. When you will harvest largely depends upon the strain, desired results, and your personal preferences.
However, the majority of the strains are ready for harvesting after two to four months of the growing cycle.
Things to remember:
If you prefer energetic high, harvest earlier. Harvest a bit later, if you like a relaxed high, with classic couchlock feeling. Remember, harvesting too early or too late may lead you to end up with a subtle effect or entirely an undesirable effect.
Quick harvesting tips
The timing of harvesting also matters to the quality of your end product. The following tips would help you to harvest timely.
- Get ready for harvesting your plants when you see at least half of the pistils on the plants are red.
- The resin gets thick and is visible to the naked eye.
- You will see plants heavy with buds and with a few yellow leaves.
- When looked through a magnifying glass, the trichomes appear white and milky.
- Finally, patience is the key to the timing of the perfect harvest.
There are a few contingencies that you need to take care of while planning to harvest your crop. Harvest a little earlier than planned when your plants are unhealthy.
In particular, when your buds look burnt or discolored, or leaves of your plants showing disease signs and it is getting worse, harvesting a little earlier is a better choice.
Sometimes curing marijuana can help fix several of the problems at the harvesting stage.
As you can realize, flowering is a critical and sensitive stage in the marijuana growth cycle. It is prone to several errors and mistakes. The careful attention and hands-on practice can enable you deal with all the issues of the flowering stage.
Therefore, pay attention to the details and avoid committing any mistakes during the flowering stage, to grow the most potent, the highest quality marijuana yield.
We hope this guide would help you to stay on the course and get a good yield.
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