How to Prepare for the Flowering Stretch When Growing Cannabis?

The flowering stage is magical — it’s when your cannabis plant starts producing beautiful resin-covered buds. But before you get too excited, there’s a speed bump you need to consider: the flowering stretch. This rapid growth spurt can double your plant's height, potentially causing you a headache if you’re short of space.

It’s a normal part of growing cannabis and isn’t a big deal if you’re prepared for it; however, it can catch you off guard if you don’t know what to expect. 

So, we will cover a few things related to the flowering stretch in this article. Learn about it and what you can do to prepare for it if you are short of space in your grow room or tent. But, first, it may help to understand the various stages of growth or lifecycle of the cannabis plant to help you understand more about your favorite plant. 

Understanding Cannabis Growth Phases

Cannabis plants undergo various growth stages that are essential for their overall development and eventual harvest. These stages include the seedling phase, vegetative phase, pre-flowering, and flowering stage. 

Seedling Phase

This is the phase after germination where the cotyledons come up. It doesn't involve any work except maintaining the plants well. You don't have to feed the plants either since they contain enough nutrients to sustain growth for a few weeks.

Vegetative Phase

The vegetative phase is when the plant experiences a lot of changes. In essence, the plant builds a foundation for its future by strengthening its leaves and roots. To thrive during this period, cannabis plants need plenty of light, water, and nutrients. Indoor growers typically expose their plants to 18 to 24 hours of light daily to simulate summer days. Outdoor plants naturally shift into this stage as daylight hours increase in spring.

During this phase, you'll have to take care of a few things, like transplanting the plants into larger containers as roots expand. You should also provide nutrients rich in nitrogen for robust vegetative growth and train the plants using a few techniques to prepare them for the flowering phase. Whatever training you wish to employ should be done in the vegetative stage only as the plants can be very fragile during the flowering phase. 

Pre flowering Phase

The pre-flowering stage indicates the shift from vegetative growth to flowering. If you're growing autoflowers, this shift will occur automatically. However, for photoperiods, you'll have to switch the lighting cycle from the 18/6 cycle to 12/12 to force the plants to start flowering. 

During this time, cannabis plants start displaying their gender characteristics — male plants develop pollen sacs while female plants show preflowers with pistils. Unless you're looking to breed the plants, you should identify and remove any males present in the growing area to prevent pollination and ensure high-quality bud production in plants.

At this point, you may also notice slight stretching as the space between the internodes widens. The leaves will also grow much more slowly compared to the previous stages of growth. 

Flowering Phase

As cannabis plants enter the flowering phase they shift their focus from growing leaves to producing flowers known as buds. This stage is crucial for developing cannabinoids and terpenes that determine the plant's effects and aroma. The duration of the flowering phase varies from one strain to another and typically lasts 7-14 weeks. To support flowering and produce buds during this phase, specific light cycles are essential.

During the flowering phase, cannabis plants not only develop bud sites but also increase resin production along with the aroma and trichome development. 

At this point, you should only maintain the plants by getting rid of any dead leaves, etc. You should also maintain a 12/12 cycle with 12 hours of light and 12 hours of darkness but there shouldn't be any light filtering through or it will ruin the plants. 

What is the Flowering Stretch?

When your cannabis plant enters the flowering stage, something happens that new growers often don’t anticipate — the plant grows vigorously in the early flowering stage. This is the flowering stretch, which can sometimes double the height of your cannabis plant. 

Let’s put it into perspective. When growing a photoperiod cannabis plant, you’re giving your plant an 18/6 lighting cycle. When your plant is ready for the flowering stage, you switch the light cycle to 12/12, which triggers the plant’s responses, encouraging it to flower. 

Once the plant starts blooming, for the first couple of weeks, it starts growing tall. Most strains only do this for two weeks, but some stretchy strains can grow well into the third or the fourth week, too. 

Why Does Cannabis Stretch?

This brings us to the next question — why does this happen? It’s important to understand this to realize whether this phenomenon is bad or not, and what you can do about it. Short answer: plant hormones make this happen. Let’s look at the long answer. 

Your cannabis plant, like the human body, has several hormones. These hormones rely on the light cycle or the daily hours of sunlight they get. When you switch the light cycle to 12/12, your cannabis plant senses this and the hormones encourage more cell growth. This results in the cannabis plant stretching. 

Charles Darwin was the first to develop the notion of plant hormones back in the 1890s when he observed plants’ growth toward the sun. This theory is known as phototropism. 

If you like getting nerdy like us, here’s more scoop on this. So far, experts have discovered eight plant hormone types, including gibberellins, ethylene, auxins, cytokinins, etc. However, experts theorize that a ninth hormone, florigen, regulates the blooming process in plants. 

That said, here are a few reasons why your cannabis plants may stretch in the flowering phase:

• Influence of Genetics

Genetics plays a big role in determining the growth traits of cannabis plants, including their tendency to stretch during the flowering stage. By having an understanding of a strain's composition, you can foresee and manage the flowering stretch successfully.

• Characteristics of Different Strains

Sativa Dominant Strains: Sativa dominant strains are recognized for their slender appearance and significant stretching during flowering. These strains come from regions where they evolved to reach sunlight in their natural environment. Sativa varieties can experience stretching where they double or even triple in height during the flowering phase. This vigorous stretching is a trait of sativa genetics and contributes to the loose airy structure seen in sativa plants.

Indica Dominant Varieties: On the other hand, indica-dominant strains typically have a more condensed bushy growth structure with minimal stretching during the flowering phase. Indicas originate from regions with quick-growing periods and harsh climates, which contribute to their compact appearance. Indica plants tend to stretch less during flowering compared to sativas resulting in internodal spacing and denser buds.

Hybrid Varieties: Hybrid strains, which combine sativa and indica genetics can showcase an array of growth traits based on their composition. Some hybrids may display characteristics inherited from their sativa parent, such as height and noticeable stretching while others may inherit features like compact growth and limited stretching. 

2. Environment 

Environmental conditions are vital for the development of cannabis plants throughout their lifecycle during the flowering stretch. Elements such as light, temperature, humidity, and airflow all play roles in shaping plant growth and stretching behavior.

• Light

Light is important for the plants but it also affects the flowering stretch. Now, you already know that cannabis strains start flowering according to the light they get. In the wild, they bloom when the days get shorter and the nights get longer. Indoors, you do the same by switching to a 12/12 cycle from the 18/6 cycle. 

Apart from that, the brightness of light also affects plant stretching. Higher light intensity typically results in shorter gaps between nodes and the plants don't stretch too much either. The plants grow bushy too. On the other hand, if the light isn't as intense as necessary, then the plants stretch more as they strive for sunlight resulting in elongated gaps between nodes and taller plants. 

You should also know that sometimes your cannabis plant may stretch due to a lack of light. This can happen at any stage of your plant’s growth. You must learn to recognize this type of stretch as it can dampen your plant’s yields if you don’t fix it on time. Hint: look for unnatural and unexpected stretches that are not your plant’s phenotype. 

• Temperature and Humidity

Temperature and humidity levels also have an impact on how much the plants stretch. 

Temperature: Optimal temperatures support proper growth and influence the extent of the flowering stretch. While slightly warmer temperatures usually promote extensive growth, there's a lot of stretching too. However, if the temps increase too much, the plants can get very stressed and affect the stretching. You may also see the leaves curling due to so much heat. 

But, don't assume that cold temperatures are great. If the temps are too cold, the plants will experience stress again and have issues stretching too. 

Thus, to prevent such issues, it's best to grow cannabis at temperatures between 68 to 77°F (20 to 25°C) during the vegetative stage and about 65 to 85°F (18 to 29°C) during the flowering stage to ensure the plants grow well without any issues. 

Humidity: Maintaining proper humidity levels is essential for preventing stress-related problems and managing plant stretch. During the flowering period, it's good to stick to a range between 40 to 60% to help plants transpire effectively without losing too much moisture through their leaves. While high humidity can lead to problems like mold and mildew, low humidity can cause stress and hinder growth.

• Air Circulation

If your grow tent lacks air circulation, your cannabis plants will not grow well. Proper airflow is crucial for regulating temperature and humidity, and preventing heat buildup. Sufficient airflow helps strengthen stems and promote growth, thereby reducing the risk of plants getting too tall. For instance, adequate airflow helps the stems become strong enough to support heavy buds during flowering. Weak stems are more likely to bend or break under the weight of their own buds, so the plant may even collapse if the buds are heavy. Fans and exhaust systems circulate lots of air in the growing space to prevent hot spots and maintain ideal conditions.

What to Expect During the Flowering Stretch? 

If you’re growing cannabis for the first time, you may not know what to do. Sometimes, you may not even see if what’s happening is good or bad. We’ve got your back. Depending on your cannabis strain, you can pretty much learn what to expect and prepare for it accordingly. 

So, first things first, always learn about the strain you are growing, whether it is a hybrid, sativa, or indica. Yes, we know that the notion of sativa-indica strains is obsolete, but that’s how breeders classify plants that grow tall or stout. 

When you learn about your strain, you’ll learn whether it tends to stretch a lot or none at all. For example, some sativa strains are known to almost double in height during the early flowering stage. 

You can also look at the average strain height mentioned by the breeder. Does it grow 200 cm or 250 cm? Some strains are inherently short and others are strong. Some strains can even stay short until the flowering stage, during which they can start reaching for the sky, metaphorically speaking. 

Sometimes, the type of light you use can also play a role in how far your cannabis plant stretches. Some light types cause this more than others. So, you should try to use the right type or spectrum of light (especially blue-dominant) to control stretching. 

Similarly, the distance of light also plays a role. Plants are always reaching for the light, so if your light source is too far, your plant may stretch more to get closer to it. 

How to Prepare for the Flowering Stretch?

Now that you know what to expect, you need to start preparing for the flowering stretch. Why is this important? Imagine this — you’re using a small grow tent but your cannabis strain is particularly stretchy — it won’t be long before the leaves touch the grow light. You’re short of space, aren’t you? 

This is just one example. Some growers may be worried about exposing their outdoor plant to their neighbors whereas others may want to keep the plant short for easier maintenance. Whatever the reason, it is always a good idea to prepare for it so your plant does not grow longer than you need it to be. 

One of the factors that influence how much a cannabis plant stretches during flowering is its genetics. Different types of cannabis strains show varying levels of stretching with some stretching more than others. Typically, indica-dominant strains tend to stretch less compared to sativa hybrid strains, which can undergo stretching as they transition into the flowering stage.

The duration of the flowering stretch phase can vary depending on factors like the strain, environmental conditions, and how the plants are grown. On average, this stretch period usually lasts between 1 to 3 weeks. In some cases, it may last even longer.

Here are some tips. 

• Again, Know the Strain You Are Growing 

As mentioned earlier, you should first understand your cannabis strain. This is the first step to accomplishing most things while growing cannabis. You can find strain characteristics of virtually all strains on the internet, so use it to your advantage. 

Know that the information isn’t always accurate, but it gives you a decent understanding of your cannabis plant. If you know your strain will grow taller than you’d like, you can prepare for things well in advance to keep the height manageable and limited. 

• Figure Out Your Plant’s Length

As reliable as online strain databases may be, they can never guess how tall your specific plant will grow. That’s down to individual genetics and the ambient environment. 

The sudden increase in plant height during the flowering stretch phase can create space constraints in indoor growing setups. Without preparation, plants might outgrow their allocated space, and become too tightly packed together leading to issues with light exposure and airflow. By anticipating this growth spurt and adjusting the growing area accordingly, you can ensure optimal spacing between plants and effectively manage their canopy. 

So, you need to figure out how tall your cannabis plant will grow. Don’t worry, it’s not that difficult. 

First, measure the ceiling height of your growing space and reduce that by the highest level your grow lights can sit it. Then, subtract that number from the height of your plant’s container. Finally, minus the amount of space you require between your green beauty and the light source. This can vary as per your grow light type. 

If you’re unsure, you can try something else. Let’s say you have two meters of space. When your cannabis plant reaches half of that, you can switch it to flowering. This way, even if your cannabis plant doubles in size, it will still not outgrow your grow space’s ceiling space. 

• Control the Flowering Stretch 

You can take a more proactive stance, too, by curbing the flowering stretch of your cannabis plant. You can do this by controlling the factors that lead to the flowering stretch. Here are some of the things you can try:

• Select the right kind of strain that won’t outgrow your growing space 
• Use MH bulbs for the early flowering stage before switching to HPS grow lights 
• Switch to bloom earlier if you’re using LEC lights since they can speed up stretching 
• Use blue-dominant LED lights to prevent excessive stretching during the early flowering stage 
• Always keep your grow lights at the right distance — neither too close nor too far

• Train Your Cannabis Plant

If you still see your cannabis plant stretching excessively, you need to employ some training methods. Of course, you can always let your plant grow by adjusting the grow lights, but if space is a concern, training is the solution. 

Here are some easy tricks to help your cannabis plant produce tons of flowers, no fancy equipment is needed.

Low-stress training or Bending and Tying 

Imagine gently pushing your plant over like a gymnast. This lets light reach all the branches, not just the top, and makes more spots for flowers to grow. It also strengthens the branches for all those heavy buds coming soon. This is the advantage of LST, but in this context, it can also help you control your cannabis plant’s height. 

ScrOG 

SCROG (Screen of Green) is a more advanced variation of LST. Here, you place a net over your plant, then as new branches grow up, tuck them under the net. This keeps your plant short and bushy, which is perfect if you don't have a lot of space. Plus, it gets light to all those tucked-in branches for even more bud production!

These techniques are perfect for beginners because they're easy and won't stress your plants out too much. Pick whichever one seems easier for you!

Support and Stability

During the rapid growth phase of flowering, cannabis plants may become top-heavy and at risk of tipping over, especially if they produce dense heavy buds. Providing support like trellises or stakes can help prevent bending or breakage due to weight, ensuring plant stability throughout the flowering period.

• Nutrient Adjustment

As cannabis plants transition from the vegetative to the flowering stage, their nutrient needs change. During the flowering phase, plants require increased levels of phosphorus and potassium to support flower formation. By adjusting the nutrients you feed them, you can ensure the plants receive the necessary nutrients for healthy flowering. Or, you can go for commercially bottled nutrients that contain everything in the proper ratios, depending on what the plants need. For beginners, this is the best option as you don’t want to mess up the ratios. 

• Nitrogen (N)

Nitrogen is a nutrient that fuels growth and overall plant well-being. When the plants are in their growing or vegetative stage, cannabis plants require nitrogen to support leafy growth and build a strong root system. However, too much nitrogen during flowering can lead to excessive stretching and delayed flower formation.

When cannabis plants enter the flowering stage, it's important to reduce nitrogen levels. Excessive nitrogen can increase the space between the nodes and the buds may be inferior in quality as well. So, to manage plant stretch during flowering, it's essential to lower nitrogen levels and focus more on providing phosphorus and potassium.

• Phosphorus (P)

Phosphorus is essential for bud development as it helps in creating compounds like ATP (adenosine triphosphate) and DNA. Adequate amounts of phosphorus during flowering supports the formation of buds and boosts the overall strength of plants. If there is a lack of phosphorus, it can result in inadequate growth and fewer flowers being produced. Thus, by ensuring a consistent supply of phosphorus, you will help with the production of resin and also prevent excessive stretching.

Potassium (K)

Another crucial nutrient for flower development and plant well-being is potassium. It plays a role in regulating water absorption, activating enzymes, and aiding in the production of carbohydrates and proteins. A deficiency in potassium during flowering can cause weak stems and the buds may be low-quality too. Increasing potassium levels while plants are flowering encourages the formation of dense buds and also reduces excessive stretching by supporting cell expansion and structural strength.

Finally, keep the pH stable at all times. Otherwise, the plants will have problems, whether the pH turns too acidic or alkaline. If you're growing in soil, the pH should be between 6 to 7. On the other hand, hydroponic plants will thrive if you adjust the pH between 5.5 to 6.5 at all times. 

Regularly checking levels and plant health is crucial, during the flowering phase. Adjusting the concentrations based on how the plants react and visual cues are key to ensuring they get the right nutrients for healthy growth. Keeping pH levels in check also helps with absorption and prevents any deficiencies or imbalances.

Summary: How to Prepare for the Flowering Stretch When Growing Cannabis?

By understanding and preparing for the flowering stretch, you can turn it from a potential problem into an opportunity. The techniques covered here allow you to optimize your grow space, promote even bud development, and ultimately, achieve a better harvest. All this, without letting your plant grow into the grow lights. 

So, embrace the stretch, take control, and watch your cannabis plants flourish with resin-rich buds! To know more about growing cannabis plants like a pro, stay tuned to our blog.