How to Increase THC or CBD Ratios in Your Cannabis Plants

Growing cannabis plants can be an exciting and rewarding experience, but for some growers, achieving high THC or CBD ratios can be challenging. To increase these ratios, a grower must understand the factors that affect them and explore various methods to enhance them. However, with so many options available, it can be overwhelming to determine which methods are the most effective. In this article, we will delve into the science behind THC and CBD and explore the various factors that can impact their ratios. We will also outline the various techniques and approaches you can use to increase the THC or CBD content of your cannabis plants.

Understanding THC and CBD


Understanding Thc And Cbd
As cannabis becomes increasingly popular as a medicinal and recreational plant, it’s important to have a basic understanding of the two most well-known compounds found in it: THC and CBD. While they come from the same plant, these two molecules have very different effects on the body and mind. In this section, we’ll dive into what THC and CBD are, as well as their unique properties and benefits.

What are THC and CBD?

THC and CBD are two of the most well-known compounds found in the marijuana plant. THC, or tetrahydrocannabinol, is the psychoactive component of marijuana, responsible for the high associated with its use. CBD, or cannabidiol, on the other hand, is a non-psychoactive compound that has been shown to have several potential therapeutic benefits.

Here’s a table summarizing some of the key differences between THC and CBD:

Psychoactive Non-psychoactive
Produces a high No intoxicating effects
Binds to CB1 receptors in the brain Doesn’t bind strongly to CB1 or CB2 receptors
May cause anxiety and paranoia in high doses Possible anxiolytic effects
Possible therapeutic benefits, such as pain relief and anti-inflammatory effects Possible therapeutic benefits, such as anti-inflammatory and anti-anxiety effects

While both THC and CBD have their unique properties and potential benefits, it’s important to note that the effects of these compounds can vary depending on several factors, including the dosage, route of consumption, and individual tolerance. Understanding the differences between THC and CBD can help cannabis growers make informed decisions about the types of strains they want to cultivate, and ultimately, the effects they want to achieve.

THC and CBD Effects and Benefits

Cannabis plants contain many compounds, but two of the most well-known and important ones are THC and CBD. THC, or tetrahydrocannabinol, is the chemical responsible for the “high” associated with cannabis use, while CBD, or cannabidiol, is a non-psychoactive compound that is becoming increasingly popular in the medical world.

THC Effects and Benefits

THC is known for its psychoactive effects, which can include a feeling of euphoria, increased appetite, and relaxation. It can also provide relief from pain, nausea, and anxiety for some users. However, it can also have negative effects, such as mood changes, impaired coordination, and short-term memory loss.

CBD Effects and Benefits

CBD, on the other hand, is not psychoactive, meaning it does not produce a “high.” Instead, it is known for its potential therapeutic effects, such as reducing inflammation, easing anxiety, and treating seizures. It has also been shown to have neuroprotective properties, meaning it may help protect the brain from damage.

Psychoactive Yes No
Potential Benefits Relief from pain, nausea, anxiety Reduces inflammation, eases anxiety, treats seizures, neuroprotective properties
Negative Effects Mood changes, impaired coordination, short-term memory loss No major negative effects reported

It is important to note that the effects of THC and CBD can vary depending on the individual and the dosage, as well as the method of consumption. It is always recommended to start with a low dose and gradually increase as needed, under the guidance of a healthcare professional.

Factors Affecting THC and CBD Ratios

Factors Affecting Thc And Cbd Ratios
When it comes to growing cannabis plants with specific cannabinoid profiles, there are a number of factors that can influence the ratios of THC and CBD. These factors involve a combination of genetics, environmental conditions, and cultivation techniques. By understanding the importance of strain selection, growing conditions, harvest techniques, soil and nutrient management, you can gain a better understanding of how to increase THC or CBD ratios in your cannabis plants. Let’s take a closer look at how each of these factors can impact the cannabinoid levels in your cannabis crop.

Strain Selection

When it comes to increasing THC and CBD ratios in your cannabis plants, choosing the right strain is crucial. Here are some important factors to consider when selecting a strain:

  • CBD- or THC-dominant: Some strains are naturally higher in CBD while others are higher in THC. Make sure you choose a strain that aligns with your desired ratio.
  • Genetics: Look for strains with a proven track record of producing high THC or CBD content. Research various strains and take note of their genetics and lineage.
  • Growth characteristics: Consider the growth characteristics of the strain, such as its height, yield, and flowering time. These factors can all influence the final THC and CBD ratio.
  • Climate: Keep in mind the climate conditions where you plan to grow your plants. Some strains are better suited for certain climates than others, and this can affect the plant’s ability to produce the desired levels of THC and CBD.

By carefully selecting your strain, you can lay the foundation for achieving your desired THC and CBD ratio. However, keep in mind that strain selection alone is not enough to guarantee high levels of THC or CBD. Other factors, such as growing conditions and techniques, also play a significant role in the final product.

Growing Conditions

The growing conditions of cannabis plants can have a significant impact on their THC and CBD ratios. Here are some of the factors to consider:

Factor Impact on THC and CBD Ratios
Temperature The temperature of the growing environment can affect the rate of THC and CBD production. Higher temperatures can result in lower CBD production and higher THC production, while cooler temperatures can increase CBD levels and decrease THC levels.
Humidity High humidity levels can increase the risk of mold and mildew, which can affect the health of the plant and ultimately its THC and CBD content. Low humidity levels can cause the plant to lose water and slow down growth, potentially resulting in lower THC and CBD levels. Ideal humidity levels for cannabis plants range from 40-60%.
Air Circulation Good air circulation helps to prevent mold and mildew, and can also increase the rate of photosynthesis, which can improve the plant’s overall health and THC and CBD production. Fans or other ventilation systems can be used to improve air circulation.
pH Levels The pH level of the growing medium can affect nutrient uptake and plant health. Ideal pH levels for cannabis plants range from 6.0 to 7.0. pH levels outside of this range can lead to nutrient deficiencies or toxicities, which can affect THC and CBD production.
Watering Overwatering or underwatering can stress the plant and affect its THC and CBD levels. Overwatering can lead to root rot and nutrient deficiencies, while underwatering can cause the plant to wilt and slow down growth. It’s important to water cannabis plants consistently and only when the top of the soil feels dry to the touch.
Nutrients The type and amount of nutrients provided to the plant can affect its THC and CBD production. Nitrogen, phosphorus, and potassium are all important for cannabis growth and can influence cannabinoid levels. It’s important to provide balanced nutrient solutions at the appropriate stage of growth.

When growing cannabis plants to increase THC or CBD levels, it’s important to consider all of these factors in order to optimize the plant’s growth and cannabinoid production. By creating a healthy and well-controlled environment, you can improve the chances of producing quality cannabis with the desired THC and CBD ratios.

Harvest and Post-Harvest Techniques

The harvest and post-harvest techniques used on your cannabis plants can have a significant impact on the final THC and CBD ratios. Below are some key techniques to keep in mind:

  • Timing: Harvesting at the right time can make all the difference in maximizing THC and CBD levels. For THC-dominant strains, harvest when trichomes start turning amber. For CBD-dominant strains, wait until the trichomes are mostly cloudy with a few amber ones.
  • Drying: Proper drying techniques are crucial for preserving THC and CBD levels. Hang plants upside down for around a week in a dark place with good air circulation. Once the stems snap instead of bend, they’re ready for curing.
  • Curing: Curing allows the remaining moisture and chlorophyll to evaporate and for terpenes to develop. Store dried cannabis in glass jars for at least a month, opening the jar daily for the first week to release moisture.
  • Trimming: While trimming, be gentle and avoid damaging the trichomes to keep THC and CBD intact. Trim away large fan leaves but leave the sugar leaves near the buds.
  • Storage: Proper storage is essential for maintaining THC and CBD levels. Store cannabis in a cool, dark place, and avoid exposure to heat and light.

By paying attention to these harvest and post-harvest techniques, you can ensure that your cannabis plants reach their maximum THC and CBD potential.

Soil and Nutrients

The soil and nutrients that you use to grow your cannabis plants can have a significant impact on the final THC and CBD ratios. Here are some factors to consider when it comes to soil and nutrients:

  • Soil Type: The type of soil you use can impact the nutrient availability for your plants. Rich, nutrient-dense soil can lead to higher THC and CBD levels.
  • Nutrient Levels: Ensuring that your soil has a balanced ratio of nutrients is crucial to help your cannabis plants thrive. Nitrogen, phosphorus, and potassium are key macronutrients that you should consider.
  • Natural vs Chemical: Some growers prefer organic or natural fertilizers and nutrients, while others prefer chemical alternatives. Ultimately, the method you choose should depend on your preferences and your grow goals.
  • pH Levels: Cannabis plants thrive in slightly acidic soil, with a pH range of 6.0 to 7.0. Keeping a stable pH level can help your plants take in nutrients more effectively, which can lead to higher THC and CBD ratios.
  • Composting: Composting is a great way to create nutrient-rich soil for your cannabis plants. By composting kitchen scraps, leftover plant matter, and other organic materials, you can create a natural fertilizer that can help boost THC and CBD levels.

Keep in mind that the soil and nutrient factors can vary depending on the strain you choose and your specific growing conditions. It’s essential to do your research and make informed decisions based on your grow goals. By paying attention to your soil and nutrient levels, you can help ensure that your cannabis plants produce high-quality buds with the desired THC and CBD ratios.

Methods for Increasing THC and CBD Ratios

Methods For Increasing Thc And Cbd Ratios
Now that we’ve covered the important factors that can affect the THC and CBD ratios in cannabis plants, let’s dive into some methods for actually increasing these ratios. From low-stress training to CO2 enrichment, there are a variety of techniques that can help increase the potency of your harvest. However, it’s important to approach these methods with caution and precision. Let’s explore some of the most effective and safe ways to increase THC and CBD levels in your plants.

Low-Stress Training

Low-stress training (LST) is a technique that involves gently bending and tying down the plants’ branches to create an even canopy. This method encourages the growth of more bud sites and promotes healthier plant development. LST is ideal for growers who want to increase their THC and CBD ratios without putting too much stress on the plants.

Steps for Low-Stress Training:
Step 1: Start LST early in the vegetative stage, around 2-3 weeks after germination.
Step 2: Identify the main stem and gently bend it over to a horizontal position.
Step 3: Use soft ties, such as pipe cleaners or gardening tape, to secure the bent stem in place.
Step 4: Repeat the process with other stems, ensuring an even and flat canopy.
Step 5: Monitor the plant during the growth cycle and adjust the ties as needed to maintain an even canopy.

It’s essential to be gentle while using LST, as too much pressure or stress can damage the plants. However, if done correctly, this method helps to distribute the plant’s energy evenly, leading to better yields and higher THC and CBD ratios. LST is also a cost-effective method that does not require any expensive equipment, making it an accessible option for all growers.

High-Stress Training

One method for increasing THC and CBD ratios in cannabis plants is high-stress training. This technique involves physically stressing the plant to the point where it produces more resin, which contains both THC and CBD.

Technique Description
Super Cropping This technique involves bending the stems of the plant until they almost break, causing the plant to produce more resin as a stress response.
Manifold Training Also known as “main-lining,” this method involves topping the main stem of the plant and training it to grow evenly on either side, resulting in multiple cola sites and increased resin production.
Fluxing This technique involves alternating between periods of high stress (such as defoliation or pruning) and low stress to encourage the plant to produce more resin.

It’s important to note that high-stress training can be risky and may lead to the plant producing less overall yield if not done correctly. It’s essential to research and prepare before attempting any high-stress techniques on your cannabis plants. It’s also important to ensure the plant is healthy and not already under too much stress before implementing any high-stress training methods.


Defoliation is a technique that involves pruning or removing leaves from the cannabis plant to increase THC and CBD ratios. It is important to note that defoliation should only be done during the vegetative stage, as removing leaves during flowering can be detrimental to the plant’s health and yield. Here are some tips for using defoliation to increase THC and CBD ratios:

  • Target large leaves: When defoliating, target larger leaves that are blocking light from reaching lower parts of the plant. This will not only increase THC and CBD production but also encourage the growth of larger and denser buds.
  • Be selective: Be selective when removing leaves and avoid removing too many at once. It is recommended to remove around 15-20% of the plant’s foliage every two weeks.
  • Don’t remove too much: Over-defoliation can lead to stress in the plant and reduce the overall yield. Always be cautious and avoid removing more than a fifth of the plant’s foliage at one go.
  • Timing: The best time for defoliation is during the vegetative stage after the plant has developed a few nodes. This will allow the plant to recover and grow more foliage before the flowering stage.
  • Be gentle: Always use clean and sharp scissors or clippers when pruning the plant to avoid causing damage or tearing. It is also important to sterilize your tools before and during the process to prevent the spread of diseases.

Defoliation is a useful method for increasing THC and CBD ratios, but it should not be done excessively or during the flowering stage. With proper timing and technique, defoliation can help promote healthy plant growth and increase overall yield.

Supplements and Additives

When it comes to increasing THC and CBD ratios in cannabis plants, supplements and additives can play a crucial role. Here are some supplements and additives that can be used to boost the cannabinoid content in your plants:

  • Beneficial Bacteria: By introducing beneficial bacteria to your soil or nutrient solution, you can improve the health and growth of your plants. This can result in increased cannabinoid production.
  • Mycorrhizal Fungi: Mycorrhizal fungi form a symbiotic relationship with plant roots, helping them absorb nutrients and water more efficiently. This can lead to healthier and more vigorous plants with higher cannabinoid content.
  • Humic and Fulvic Acids: Humic and fulvic acids can improve soil quality and nutrient uptake in cannabis plants, leading to higher cannabinoid production.
  • Kelp Extract: Kelp extract is rich in micronutrients and plant growth regulators, which can promote healthy growth and higher cannabinoid production in cannabis plants.
  • Molasses: Adding molasses to your soil or nutrient solution can provide a food source for beneficial microorganisms in the soil, leading to improved plant health and higher cannabinoid content.

It’s worth noting that supplements and additives should be used in moderation and with caution. Overusing them can lead to nutrient imbalances and other issues that can negatively impact plant health and cannabinoid production. It’s always best to start with a small amount and gradually increase as needed, while monitoring your plants closely for any signs of nutrient deficiencies or other problems.

CO2 Enrichment

One method for increasing THC and CBD ratios in cannabis plants is CO2 enrichment. Carbon dioxide (CO2) is essential for plants to perform photosynthesis, which is the process by which they create energy from sunlight, water, and carbon dioxide. Increasing the amount of CO2 available to the plants can stimulate their growth and increase their potency.

Here are some key points to keep in mind when using CO2 enrichment as a method for increasing THC and CBD ratios:

  • Controlled Environment: CO2 enrichment works best in a controlled environment, such as a greenhouse, where the levels of CO2 can be closely monitored and adjusted.
  • Monitor CO2 Levels: It is important to monitor the CO2 levels in the growing environment to ensure that they remain within optimal ranges (around 1000-1500 ppm). Too much CO2 can be harmful to the plants.
  • Timing: CO2 enrichment should be implemented during the flowering stage of the plant, which is when THC and CBD are produced in the greatest amounts.
  • Duration: CO2 enrichment should not be used for extended periods of time, as it can lead to a decrease in terpene production and overall quality of the buds.

When implementing CO2 enrichment, there are different methods to choose from. One option is to use a CO2 generator, which releases the gas into the growing environment. Another option is to use CO2 tanks or burners, which can be more expensive but offer greater control over the levels of CO2 being released.

CO2 enrichment can be an effective method for increasing THC and CBD ratios in cannabis plants, but it requires careful monitoring and timing to ensure optimal results.


Proper lighting is crucial for boosting THC and CBD levels in cannabis plants. Here are some factors to consider when it comes to lighting:

  • Light spectrum: Cannabis plants require a specific spectrum of light to grow and produce high levels of THC and CBD. During the vegetative stage, plants require higher levels of blue spectrum light, while during flowering, they need more red spectrum light. It’s essential to choose a grow light that provides the optimal spectrum for each stage to increase THC and CBD ratios.
  • Light intensity: The intensity of light also plays a crucial role in plant growth and cannabinoid production. Make sure to provide enough light to your plants, but be careful not to overdo it, as excessive light can cause stress and reduce THC levels. The ideal intensity is between 600-1000 μmol/m²/s for most cannabis plants.
  • Light duration: The duration of light exposure also affects THC and CBD ratios. During the vegetative phase, cannabis plants require 18-24 hours of light per day, while during the flowering phase, they need 12 hours of light and 12 hours of darkness. Maintaining consistent light durations throughout each phase is crucial in boosting cannabinoid production.
  • Light distance: The distance between your grow lights and your plants is also important for maximizing THC and CBD levels. Keeping lights too far away can reduce light intensity and affect plant growth, while keeping them too close can cause heat stress and damage to the plants. The ideal distance between the grow lights and plants depends on the type of light being used, but a general rule of thumb is to keep them at least 12-18 inches away from the plants.

By optimizing lighting conditions for your cannabis plants, you can significantly increase THC and CBD ratios for a more potent and beneficial end product.

Cold Shock

One method for increasing THC and CBD ratios in cannabis plants is through the use of cold shock. This technique involves exposing the plants to a sudden drop in temperature, which can stimulate the production of THC and CBD.

To use this method effectively, it is important to follow a few key steps:

Step 1: Reduce the temperature in the grow room or grow tent to around 50-60 degrees Fahrenheit for 1-2 days.
Step 2: Return the temperature to normal levels for a few days, then repeat the cold shock process once more.
Step 3: Monitor the plants closely and adjust the duration and intensity of the cold shock as needed.

It is important to note that cold shock can also stress the plants, so it is crucial to use this method with caution and only on healthy, mature plants. Additionally, it may not be effective for all strains, as certain genetics may respond differently to this technique.

While cold shock can be an effective method for increasing THC and CBD ratios, it should not be relied upon as the sole method for achieving optimal cannabinoid levels. A combination of various techniques and factors, such as strain selection and proper growing conditions, should be considered for best results.

Common Mistakes

When trying to increase THC or CBD ratios in cannabis plants, there are a number of common mistakes that growers should be aware of in order to avoid them. These mistakes can not only be costly in terms of time and resources, but can also have a negative impact on the final product.

Choosing the Wrong Strain: One of the most common mistakes that growers make is choosing a strain that is not suited for their desired THC or CBD ratio. It’s important to do your research and choose a strain that has the potential to produce the desired levels of cannabinoids.

Overfeeding or Underfeeding: Nutrient management is critical to maximizing the potency of your cannabis plants. Overfeeding can lead to nutrient burn, while underfeeding can stunt growth and reduce yield. It’s important to carefully monitor the nutrient levels in your soil and adjust accordingly.

Ignoring pH Levels: pH levels can have a major impact on the health and growth of your plants. Cannabis plants prefer a slightly acidic pH level, usually between 6.0 and 6.5. Ignoring pH levels can lead to nutrient lockout and other issues.

Improper Harvesting: Harvesting at the wrong time can have a significant impact on the potency of your final product. Waiting too long can result in a loss of potency, while harvesting too early can result in immature trichomes and a lack of potency.

Not Providing Enough Light: Light is essential to the growth and development of cannabis plants, and insufficient lighting can lead to stunted growth and reduced potency. Make sure your plants are getting plenty of light, particularly during the flowering stage.

Ignoring Environmental Variables: Environmental variables, such as temperature and humidity, can have a major impact on the growth and health of your cannabis plants. Ignoring these variables can lead to a wide range of issues, including stunted growth, nutrient deficiencies, and reduced potency.

Not Practicing Proper Pest Management: Pests can quickly destroy a cannabis crop, and ignoring proper pest management practices can result in significant losses. Make sure to monitor your plants regularly for pests and take appropriate action if necessary.

By avoiding these common mistakes and taking a proactive approach to cannabis cultivation, growers can maximize their yields and produce high-potency cannabis plants with the desired THC or CBD ratios.


In conclusion, increasing the THC or CBD ratios in your cannabis plants can be challenging, but it is achievable with careful attention to detail and proper techniques. It is crucial to understand the factors affecting ratios, including strain selection, growing conditions, harvest and post-harvest techniques, and soil and nutrient management. By controlling these factors and using various methods such as low-stress training, high-stress training, defoliation, supplements and additives, CO2 enrichment, lighting, and cold shock, you can increase THC or CBD levels in your plants.

However, it is essential to avoid common mistakes such as over-fertilizing, using improper pruning techniques, and not providing adequate lighting or air circulation. These mistakes can negatively impact plant growth and result in lower THC or CBD levels.

Furthermore, it’s important to note that increasing THC levels may not always result in a better experience, as higher THC levels can be overwhelming or cause anxiety in some individuals. Therefore, it’s vital to consider personal preferences and the desired effects when selecting strains and altering cultivation techniques.

Overall, achieving the desired THC and CBD ratios requires dedication, patience, and a thorough understanding of the plant’s growth and development. By implementing the methods and avoiding common mistakes, you can increase THC or CBD ratios in your plants and produce high-quality cannabis that meets your needs and preferences.

Frequently Asked Questions

Can I increase THC and CBD levels in my cannabis plants?

Yes, you can increase THC and CBD levels in your cannabis plants by following certain methods and techniques.

What are the factors affecting THC and CBD ratios in cannabis plants?

Factors affecting THC and CBD ratios in cannabis plants include strain selection, growing conditions, harvest and post-harvest techniques, and soil and nutrients.

Is strain selection important for increasing THC and CBD levels?

Yes, strain selection is important as some strains naturally have higher levels of THC or CBD, so selecting the right strain is crucial for achieving desired ratios.

What are some low-stress training techniques for increasing THC and CBD ratios?

Low-stress training techniques like topping, bending, and SCROG can help increase THC and CBD ratios in cannabis plants while also promoting even growth.

What are some high-stress training techniques for increasing THC and CBD ratios?

High-stress training techniques like super cropping and FIMing can induce stress in the plants, which can lead to higher THC and CBD levels as a natural defense mechanism.

What is defoliation and how can it increase THC and CBD ratios?

Defoliation is the removal of leaves and foliage from the lower parts of the plant, allowing more energy to be directed towards the buds which can lead to higher THC and CBD ratios.

Can supplements and additives help increase THC and CBD ratios?

Yes, supplements and additives like molasses, kelp extract, and bat guano can provide essential nutrients to the plant and promote higher THC and CBD levels.

What is CO2 enrichment and how does it increase THC and CBD ratios?

CO2 enrichment is the process of increasing the concentration of CO2 in the grow room to promote photosynthesis, which can lead to higher THC and CBD levels in the plant.

Can lighting affect THC and CBD ratios in cannabis plants?

Yes, the type of lighting and the duration of light exposure can have an impact on THC and CBD ratios. Using high-intensity LED lights or switching to a 12/12 light cycle during flowering can help increase THC and CBD levels.

What is cold shock and how can it increase THC and CBD ratios?

Cold shock is the process of exposing the plant to lower temperatures during the final weeks of flowering. This can induce stress and increase THC and CBD levels as a natural defense mechanism.


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