Photoperiodic lighting of crops – what is it about?

Photoperiodic lighting of crops is used by experienced growers.

Photoperiodic lighting of crops involves artificially extending the light day for plants to influence their growth, development and flowering. This is especially important in the case of plants whose development is directly related to the amount of light during the day, i.e. photoperiod plants. Marijuana (most of its varieties) is also such a plant.

In nature, the length of day and night varies throughout the year (except at the equator, where day and night always last 12 hours), which signals plants to changes in their life cycles, such as the beginning of the flowering phase. In controlled cultivation, e.g. in greenhouses or indoor cultivation (e.g. in special grow boxes), additional lighting allows growers to imitate these natural light conditions, which is crucial for optimal growth and development of plants.

For example, in marijuana, lighting is used to mimic the longer days of summer during the vegetative phase (usually using 18 hours of light and 6 hours of darkness) and the shorter days of fall during the flowering phase (using 12 hours of light and 12 hours of darkness). This allows you to control the flowering time of your plants and increasing crop productivity.

Various types of lighting are used for lighting, including sodium lamps (HPS), metal halide lamps (MH) and modern LEDs, which can be adapted to the needs of specific plants and their growth stages. Growers can precisely control the amount and quality of light, which has a direct impact on plant health and performance.

Choosing a photoperiod variety – which one?

The type of hemp variety determines what photoperiodic lighting of crops will ultimately look like.

Photoperiod marijuana strains are those strains that require alternating day and night lengths to flower. In other words, the beginning of the flowering process in these plants is triggered by the shortening of the light day, which imitates the natural changes that occur with the arrival of late summer and early autumn.

Indoors, the grower decides to change the plants’ light cycle from “vegetative” to “flowering.” During the vegetative phase, photoperiod plants typically receive 18 hours of light and 6 hours of darkness each day. Once the plant reaches the appropriate size or age, the grower changes the cycle to 12 hours of light and 12 hours of darkness, which induces flowering.

Photoperiod varieties are different from autoflowering varieties, which flower automatically after a specific ("programmed" in genetics) time, regardless of the light cycle. Photoperiod marijuana strains are often preferred by experienced growers because they allow for greater control over the size and flowering time of the plant, thus resulting in potentially better quality and quantity of yield. These varieties can simply grow longer because the vegetation phase is extended, which means they can reach up to several meters in height. Of course, it all depends on genes and breeding conditions.

Full-season varieties

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cannabis varieties

Full season marijuana seeds

How to properly perform photoperiodic lighting of cannabis crops?

Correctly carrying out the process of illuminating photoperiodic marijuana crops requires careful planning and following several key rules. First of all, it is crucial choosing the right lighting. For marijuana in the vegetative phase, metal halide (MH) lamps or LED diodes emitting light with a cool color temperature are recommended, which support the development of plants. During the flowering phase, sodium lamps (HPS) or LED lamps are best, emitting warmer light that promotes flowering.

Then you need to pay attention to light cycle. During the vegetative phase, marijuana requires approx 18 hours of light and 6 hours of darkness daily. When the plant is ready to flower, the cycle changes to 12 hours of light and 12 hours of darknessto mimic the shorter days of fall. The next step is to ensure the stability of the light cycle. It is very important to maintain the regularity of the light cycle. Sudden changes should be avoided as they can stress the plants and affect their growth.

Control light intensity, is necessary to properly carry out photoperiodic lighting of crops. Just make sure the plants receive the right amount of light. Too little light can stunt growth, while too much can burn plants. The optimal light intensity depends on the plant's growth phase and the type of lighting used.

The distance from light is equally important. Lamps should be placed at an appropriate distance from the plants. Too close - plants may be burned; too far away - they may not receive enough light.

You should also ensure appropriate temperature and air circulation in the growing room. Excessive temperature and lack of fresh air can negatively affect plants. Therefore, during the entire process of illuminating photoperiod crops, you must regularly check the condition of the plants and adjust the conditions if necessary. Observing the growth process and responding to problems develops the grower, making his plants more healthy, impressive and yielding.

It is worth remembering that each variety of marijuana has slightly different needs, so it is important to adapt the photoperiodic lighting of crops to the specific requirements of the selected variety.

ATTENTION! In Poland, the law prohibits the cultivation of hemp other than fiber. This entry is not intended to encourage breaking the law. All content related to the cultivation and processing of marijuana is for educational and interesting purposes only. Currently, more and more countries in the world allow their citizens to grow marijuana for their own use, but Poland is not one of these countries yet.

What is the difference between lighting the cultivation of photoperiod varieties and automatic varieties?

Lighting photoperiod marijuana plants differs significantly from lighting autoflowering plants. Here are the main differences:

Light cycle in photoperiod: Photoperiod varieties require a change in the light cycle to induce flowering. During the vegetative phase, they typically receive 18 hours of light and 6 hours of darkness. To start flowering, the light cycle must be changed to 12 hours of light and 12 hours of darkness. The grower controls this process by adjusting the lighting.
Constant light cycle in automatic varieties: Automatic varieties do not require changing the light cycle for flowering. They can flower in almost any light cycle, although 18/6 or 20/4 (light/dark) is most common throughout the plant's life cycle. This means that lighting in the case of automatic varieties is much simpler and does not require changing light settings during growth.
Greater control over photoperiods: Growers often choose photoperiod varieties because they allow for greater control over the size and flowering time of the plants. They can be kept in the vegetative phase for as long as necessary to reach the desired size.
The ease of automatic cultivation: Automatic strains are often preferred by beginner growers due to their simple cultivation. They do not require changing the light cycle, which simplifies the growing process.

The main difference in lighting these two types of marijuana strains is the need to change the light cycle to induce flowering in photoperiod strains, while automatic strains flower regardless of changes in lighting. Simply photoperiodic lighting of crops requires some skill and experience.

Where is it better to grow photoperiod marijuana strains – indoors or outdoors?

The choice between growing photoperiod marijuana strains indoors or outdoors depends on several factors and the grower's preferences:

Control of growing conditions (Indoor): Growing indoors gives you full control over the environment, including light cycle, temperature, humidity and access to nutrients. This allows breeders to precisely control the plant's life cycle, which is especially important for photoperiod varieties that require a change in the light cycle for flowering.

Natural conditions (Outdoor): Growing outdoors allows plants to benefit from sunlight, which is a natural and effective light source. However, growers are dependent on weather and seasonal conditions, which can be a limitation for photoperiod varieties as day length must naturally change to induce flowering.

Costs and resources (Indoor vs Outdoor): Indoor growing requires an investment in equipment, such as lights, ventilation systems, and climate control, which can be expensive. Outdoor growing is generally cheaper but less controlled.

Security and discretion: Indoor growing allows for greater discretion and protection of plants from thieves and pests. Outdoor growing may be more vulnerable to these threats.

Quality and quantity of the crop: Indoor cultivation can produce high-quality crops all year round, regardless of weather conditions. Outdoor cultivation can produce higher yields, but is dependent on season and climate conditions.

The choice between indoor and outdoor growing depends on many factors, including resource availability, grower skill, climate conditions, and growing goals. Photoperiod strains can be successfully grown in both controlled (indoor) and natural (outdoor) environments, but each method has its own unique advantages and challenges.

Lighting automatic varieties

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Summation

Photoperiodic lighting of crops is a key element in the cultivation of photoperiod plants such as marijuana. This process involves artificially extending the light day or changing the light/dark ratio to control the stages of a plant's life, particularly the transition from the vegetative to flowering phase.

Indoor growers use different types of lighting (e.g. LED) to adjust the amount and quality of light to the needs of the plants. During the vegetative phase, plants usually receive more light (e.g. 18 hours of light and 6 hours of darkness), and during the flowering phase, less light (e.g. 12 hours of light and 12 hours of darkness).

It is crucial to maintain a regular and stable light cycle, as irregularities can disrupt plant growth and development. In addition, growers must pay attention to the appropriate light intensity and the distance of the light source from the plants to avoid damaging them.

Photoperiodic lighting allows for greater control over the plant's life cycle, which is particularly important in the cultivation of photoperiod plants such as marijuana, enabling growers to optimize conditions to obtain the best quality and quantity of the crop.

Before starting cultivation, we recommend that you familiarize yourself with the applicable law. We do not encourage anyone to break the law with this entry or any content posted on the website.

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Disclaimer

WARNING! In Poland, the law prohibits the cultivation of hemp other than fibrous. This post is not intended to encourage you to break the law. All content related to the cultivation and processing of marijuana is for educational and curiosity purposes only. Currently, more and more countries in the world allow their citizens to grow a marijuana bush for their own use, but Poland is not one of these countries yet.

What is photoperiodic lighting of crops?

What is photoperiodic lighting of crops?

8 January, 2024

Photoperiodic lighting of crops – what is it about?