You’ve decided to start your own cannabis grow: you’ve got your seeds ready, your space prepared, and you’ve got the excitement of watching your first plant grow. But the big question arises: how long will it take until you can see the results of your effort? Cannabis cultivation is a fascinating process that involves different stages, each with its own rhythm and particularities. From germination to harvest, multiple factors influence the development of the plant, such as the variety chosen, the environmental conditions, and the cultivation techniques applied. If you’ve been wondering how long the cannabis life cycle lasts and how to optimize each of its phases, here’s a detailed guide to help you plan and improve your grow efficiently.
Cannabis growth phases
Each cannabis plant goes through different stages of development, each with specific characteristics and times. Knowing these periods is essential to ensure healthy growth and maximize the final yield. Proper planning in each phase of the cycle will allow you to obtain strong plants with good production.
Germination (1-7 days)
Germination is the starting point in the cannabis life cycle. In this phase, the seed absorbs water, expands and breaks its shell to make way for the taproot. This time is crucial, as poor germination can compromise the growth of the plant from the beginning.
Key factors for successful germination
- Humidity: A humid environment favors the activation of the seed. It is recommended to place it on damp paper napkins or directly in an aerated culture medium. If the environment is too dry, the seed will not open; If it’s too wet, it can rot.
- Temperature: Keeping the temperature between 20-25ºC helps to speed up the process. If it is too cold, germination may take more days or even not at all.
- Oxygen: A well-aerated environment allows the seed to breathe and sprout properly. Therefore, it is advisable to avoid substrates that are too compact.
Seedling Stage (2-3 weeks)
Once the seed germinates, the seedling appears. At this stage, the plant develops its first true leaves and begins to strengthen its structure. It is a delicate phase, as seedlings are fragile and require specific care.
Initial care:
- Provide soft light for at least 18 hours a day. Too much light can burn the seedling, while too little light can weaken it.
- Avoid overwatering to prevent root rot. A substrate that is too wet can drown the plant at this early stage.
- Maintain a relative humidity of 60-70% for stable growth. A dry environment can slow down seedling development and cause its leaves to become brittle.
Vegetative growth (3-16 weeks)
This phase is crucial, as here the plant experiences accelerated growth in height and leaf development. This is the period when the plant becomes stronger and more resistant, accumulating the energy it will need in flowering.
Key aspects:
- Photoperiod: In indoor cultivation, 18 hours of light and 6 hours of darkness are recommended. Constant light allows for faster and more vigorous development.
- Nutrition: Increased amount of nitrogen for vigorous foliage. At this stage, a fertilizer with a high nitrogen content is essential to strengthen the plant.
- Space: It’s important to leave enough space between plants to avoid competition for light. Growing too tightly can lead to ventilation problems and diseases.
Pre-flowering (10-14 days)
At this stage, the plant begins to show signs of its sex. If female, pre-flowers appear with white pistils; if male, it develops pollen sacs. This is the time when growers need to decide what to do with male plants if their goal is to obtain seedless buds.
Recommended actions:
- Identify and separate male plants if pollination is not desired. An oversight at this point can affect the entire harvest.
- Reduce relative humidity to 50-60% to avoid diseases, especially mold, which can affect developing flowers.
Flowering and maturation (6-12 weeks)
Flowering is the most anticipated phase, where the plant produces its floral structures and increases the amount of resin. This is where the previous effort begins to pay off.
Factors to consider:
- Change the photoperiod to 12 hours of light and 12 hours of darkness to induce flowering in photoperiod crops.
- Ensure good airflow to avoid mold and other problems derived from humidity.
- Use fertilizers rich in phosphorus and potassium to promote flower production and increase bud density.
Factors That Affect Growing Time
Plant Genetics
Genetics is one of the most determining factors in the growth time of a cannabis plant. Depending on the variety grown, the life cycle can be shorter or longer, affecting germination time, vegetative development, and flowering.
- Cannabis Indica: Shorter life cycle, compact plants with faster flowering. These varieties usually complete their cycle in a period of 8 to 10 weeks from germination, which makes them ideal for cold climates or for crops where a quick harvest is sought. Their dense and robust structure makes them more resistant to wind and low temperatures, but they can also be more prone to moisture in their buds.
- Cannabis Sativa: Prolonged growth, tall plants that may take longer to bloom. Generally, sativas require 12 to 16 weeks to reach maturity. They do best in warm climates with long periods of sunlight. Their vigorous growth and imposing height can be challenging in tight spaces, so they often need pruning and control techniques to manage their size.
- Autoflowers: Fast development, ready for harvest in 8-10 weeks without the need for photoperiod changes. These strains are the result of crossing with Cannabis ruderalis, allowing them to flower regardless of the light cycle. They are perfect for those looking for discreet crops or multiple harvests in the same year, although their yield is usually lower than that of photoperiod varieties.
Environmental conditions
The environment where cannabis is grown significantly influences the speed of growth and the overall health of the plant. Controlling factors such as temperature, humidity and air quality is essential to ensure optimal development.
- Temperature: Ideally between 20-28ºC for optimal development. Temperatures below 15ºC can slow down growth and affect nutrient uptake, while temperatures above 30ºC can lead to water stress and deterioration in resin production.
- Humidity: Controlled according to the stage of growth to avoid diseases. In the seedling stage, a relative humidity of 60-70% is recommended to promote rooting. During flowering, it is crucial to reduce humidity to 40-50% to prevent mold and mildew from growing on the buds. An efficient ventilation system is key to maintaining a proper balance.
Light quality and photoperiod
Light is an essential factor in plant development, as it directly influences photosynthesis and energy production. Adapting the photoperiod and the type of lighting to the growth cycle of the plant will allow for better results.
- Intense light during the vegetative phase for optimal growth. In indoor grows, LED and HPS lights are popular choices. It is recommended to maintain a photoperiod of 18 hours of light and 6 hours of darkness to stimulate vigorous growth.
- Reduction of hours of light in flowering to induce flower development. For photoperiod varieties, reducing to a 12/12 cycle (12 hours of light and 12 hours of darkness) activates the flowering process. The red light and warm spectrum favor the formation of dense and resinous buds.
Advanced techniques to optimize growth
Indoor vs. outdoor cultivation
The choice between growing cannabis indoors or outdoors will depend on the available environmental conditions, the level of control you want to have, and your financial resources. Both methods present advantages and challenges.
- Interior: Total control of the environment, less risk of pests, but greater investment. Growers can adjust the temperature, humidity, and photoperiod to maximize yield. However, electricity consumption and investment in lighting and ventilation equipment can be high. It is also essential to manage air circulation to avoid accumulations of heat and humidity.
- Outside: Use of natural light, greater potential production, although subject to climatic conditions. In favorable climates, outdoor cultivation allows plants to reach their maximum size without restrictions. However, pest control and climate variability can pose challenges, especially in regions with frequent rainfall or sudden changes in temperature.
Training methods
To maximize production and improve light distribution in the crop, various training techniques can be employed that optimize the structure of the plant.
- SCROG (Screen of Green): Use of meshes to better distribute light and maximize production. This method involves placing a mesh above the plants and training their branches to grow horizontally. This allows for better light penetration throughout the plant’s structure, which increases flower production and improves the overall quality of the harvest.
- SOG (Sea of Green): More plants with shorter growth time, ideal for commercial crops. In this system, many small plants are grown in a small space, allowing for more frequent and efficient harvests. It’s a useful technique for those looking to optimize indoor production.
Using Greenhouses and Combined Crops
The use of greenhouses represents an intermediate solution between indoor and outdoor cultivation, combining the best of both methods.
- Protection against extreme weather and greater control over environmental conditions. Greenhouses protect plants from adverse weather conditions such as frost, heavy rain, or extreme temperatures. In addition, they allow the growing season to be extended in regions with marked seasons.
- Temperature and humidity regulation without the need for expensive infrastructure. While greenhouses can be an initial investment, in the long term they help reduce operating costs by taking advantage of natural light and minimizing the use of electrical equipment such as lamps or heaters. With proper ventilation and irrigation management, growers can obtain high-quality harvests more efficiently.
For those looking to optimize their cannabis cultivation, understanding the differences between strains and applying advanced methods, such as controlling lighting, humidity, and plant nutrition is key to achieving healthy growth and maximizing yields. SCROG or SOG can make a difference in the quality and quantity of the harvest. There is no one-size-fits-all formula, but with the right information and careful handling, any grower can improve their experience and achieve satisfactory results. So if you’re just starting out in this world, keep each of these aspects in mind and get ready to enjoy a well-planned and successful grow. And while your plants grow, get the best quality CBD flowers supported by sustainable cultivation techniques in Maionais!
References
- Ángeles López, Guadalupe Esther, Brindis, Fernando, Cristians Niizawa, Sol, & Ventura Martínez, Rosa. (2014). Cannabis sativa L., a unique plant. Mexican Journal of Pharmaceutical Sciences, 45(4), 1-6. Retrieved March 11, 2025, from http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1870-01952014000400004&lng=es&tlng=es.
