Best Light Cycle for Flowering

The most important aspect of growing plants is being able to produce a proper harvest each time. Even if growing plants is a profitable venture, it involves various intricate details if you want the best results. Perhaps one of the most crucial aspects of growing plants that people forget is the lighting cycle. Lighting is vital for your plants both indoors and outdoors. The quality of light you play a significant role in the quality of harvest you can get from a given plant. More so, different plant species have as many different light cycle requirements. Thus, choosing a proper light cycle can improve the quality of your plant`s yield significantly.

There are two points during the plant growth process where you need to monitor the light cycle.

The Vegetative Stage Light Cycle

This is the at which the plants are growing. This stage is vital for the health and quality of harvest of the plant. More so, this is the stage where the leaves of the plant are likely to increase in growth significantly. That said, the plant might not produce any fruit at this point, and you might have to regulate the size and shape of the plant. This is where the light cycle comes in because manipulating the light quality at this point has various benefits. Being able to expose your plant to high-quality light will improve its yield significantly. 

When marijuana plants are in a vegetative state, consider placing them under 18 hours of light. However, if you are a grower who loves big plants, then consider using the 24/0 indoor cycle. Most plants won’t flower until they are experiencing an average of 12 hours of darkness. If the plants get more than 14 hours of light each day, you can keep them at this growth stage for a long time. 

vegetative stage

The vegetative cycle also classifies into two major categories. They include:

  • Indoor vegetative stage – at this point, you should note that the plants require various other resources for optimal growth. If you grow the plants indoors, you want to get a good grow room with all the proper plant health resources. Besides, it’s essential to note that some plants species are hardy, and are likely to produce high-quality yield regardless of the conditions. 
  • Outdoor vegetative stage – In most cases, growers should start growing plants indoors before relocating the outdoors. The common practice for farmers is to either begin producing clones or use starting seeds in March or April. Also, the farmer has to maintain an average of 18 to 24 hours of light before relocating the plants outdoors in the following months of May and June.

If you want to grow cannabis plants outdoors, you will benefit from keeping them indoors until issues such as winter weather has passed. Any compromise in the temperature or increased humidity is likely to have adverse effects on the yield. 

However, once such issues are over, the plants will grow in the vegetative stage outside from late in the spring to summer.

The Flowering Stage Light Cycle

If you want your plants to transition to the flowering stage, you need to expose them to an average of 12 hours of darkness each day. This the same condition that plants would experience when growing in outdoor conditions. Here are some other critical factors about flowering, both indoors and outdoors:

flowering stage

Flowering Indoors

Most farmers that grow plants indoors use the 12-hour light cycle once the plants reach the desired size and shape level in the vegetative stage.

Furthermore, the common practice is to keep the plants indoors in the vegetative stage and use the 24/0 and 18/6 light cycles

To grow a flowering plant indoors successfully, you have to provide it with the natural elements that accommodate its growth. When you grow the plant outdoors, it might start producing fruit as the days become shorter, and the plants get 12 hours of darkness. To achieve this, adjust the light cycle from 18 to 24 hours of adequate sunlight.

Flowering Outdoors

If you want to grow plants outdoors, you have little or no control over a few elements. Thus, choose a proper growing location to achieve the best yield. At this point, most plants should start flowering naturally, which often occurs late in June, as the length of a day decreases.

However, the plants will keep on growing and producing flowers as the days progress. In most cases, the plants will start increasing in height and size as they enter the flowering stage. This concept applies to both indoor and outdoor plants. You may have to ensure that the plant stays in full darkness to avoid any light cycle issues that might affect the growth of the plant.

Scheduling Your Light Cycles for Maximum Yield

Do you want to grow your plants indoors or outdoors? It’s important to understand that light cycles for a seedling so that you can choose the best light cycle for the plant. If you can select a proper lighting plan, then you are likely to get the best yield. If you are growing the plants indoors, the best approach is to use the 18/6 or 24/0 light cycle in the vegetative stage. On average, you should leave the plant at this stage for two months, which is ideal for flowering.

On the contrary, if you want to grow plants outdoors, then the flowering cycle should be 18/7 or 24/0. That said, you will have to keep the plants indoors until the winter season passes. After that, you can bring the plants outdoors and place them in the best plant growth location. At this point, the plants will rely on the natural light cycle of the sun. 

If you apply a proper light cycle, then you should expect the plants to grow fast and to produce an outstanding harvest.

Benefits of the 6/2 light Cycle

Various studies show plants can only process a specific amount of light per day. Anything past that and the plant won’t absorb the light produced, and this will all go to waste. Thus, by dividing the light cycle into several six-hour periods, the plant can rest and absorb the light it receives. After 2 hours of rest, the plant should be ready to absorb additional light.

Based on biological factors, the inability to grow more once the plant is exposed to some light is attributed to the way plants break down carbon dioxide. Most of the mass a plant will accumulate relates to the amount of CO2 it receives at a given point in time. When exposed to optimal light, cannabis plants can prevent C02 from leaving the cells by reducing the level of transpiration. That said, this stops any new CO2 from entering the plant, which might compromise the growth of the plant. When you turn off the lights and photosynthesis stops, then the plant will absorb C02 in its cells. 

Furthermore, when plants are exposed to 18 hours of light, they might become fatigued. The common issues associated with fatigue include curled leaves, yellowness, and more. These issues will often appear during the end of the light cycle of the flowering plant. While some stress can be beneficial for plant growth, exposing the plant to excessive stress levels is harmful. 

Providing the plants with six hours of light at a time will not only place minimal stress on the plants, but it also helps to reduce the load on your cooling system. Most cooling systems work hardest when you have the grow lights on. 

By exposing the plants to two hours of darkness through the day, the cooling system will get sufficient rest. Thus, this allows the room to cool to a specific temperature before you can restore the lights. With a proper cooling system, you improve the rate can grow and reach the flowering stage. 

Even if there are several light cycle recommendations for plants, the 6/2 light cycle ensures the best growth results. The 6/2 light schedule means that the plants can process more light and get adequate rest at the same time. Thus, this approach puts minimal stress on the plants, and it’s the best light cycle for flowering.

What Does Light Cycle Mean?

This term refers to the cycle of darkness and light which a plant receives during the growth stage. There are various approaches when it comes to light cycles, and this has an impact on the yield and flowering of the plant. Moreover, the light cycle is an essential factor to consider for indoor and hydroponic gardeners with minimal access to the light cycle. 

Similar to all living things, plants have a preferred light cycle, which consists of specific durations of darkness and light. During the winter season, the evergreen plants tend to undergo long durations darkness and short periods of light. However, as the spring season comes through, the number of hours the plant is exposed to light increases, while the darkness reduces. Furthermore, in summer, plants tend to experience long durations of light, with short durations of darkness. This pattern often starts to reverse as the plant’s transition to fall and winter. 

Different periods of light and darkness will affect plants in different ways. Moreover, different types of plants are affected in myriad ways from varying light cycles. For instance, a cycle of 12 hours of light and 12 hours of dark will encourage basil not to flower, but to put its energy into healthy vegetative growth.

For other plant species, the preferred lighting schedules might be 24 hours of light, which prevents flowering. The time of the year is a crucial factor to consider in the flowering of plants. For instance, rosemary plants might flower in the spring but will produce buds in fall or early in the winter. Thus, discoursing the blooming process might require conditions that are similar to winter and summer, but not identical to that of the spring season. 

The light cycle is only one of the factors that are crucial for plant growth and flowering. Various other factors come into play, such as water and temperature. A lack of water can cause plants to bloom prematurely, and the same applies to increased temperatures. If a plant is prone to bolting in hot conditions, then you might require colder conditions to stop the blooming process. That said, if the plant fails to receive adequate water for development and growth, it will transfer the available energy into reproduction. At this point, the plant views this an impending drought, and reproduction is crucial.

Pitch Black – No Light Pollution Allowed

Light pollution is one of the biggest challenges when you want to grow a set of plants. Your grow room should be well-sealed to ensure the plants receive the proper light and dark conditions. Failing to do so can easily compromise the quality of the yield. 

There are various natural interruptions to the natural growth of plants, such as clouds. Plants such as cannabis can handle this. However, any conditions with no light pollution during this time will be sufficient for some plant strains. Any light that leaks into the growing area is likely to stress plants, and compromise the growth process. This can even cause stress on the female plant, which might cause it to become intersex. Resources such as street light can also compromise the photoperiod of some plants, and stop the flowering period. At this point, you can only use a green bulb if you must keep track of the plants or go to the garden in the dark cycle. 

You also have to monitor the grow tents and grow rooms regularly for tears and cracks. You can also cover the greenhouse to ensure that plants never experience any darkness during the night period. Any interruptions to the light cycle of the plants could affect your entire harvest.

Flowering 12-12 for Indoor Growing

The equal split of 12 hours of daylight and night darkness occurs in places that are close to the equator. The indoor growers have to use timers to realize this light and dark cycle. During the day, various light receptors are in balance, which is vital for plant growth. In the darkness, the receptors change to adjust the lighting conditions. Any change in the receptors leads to flowering. Most growers place their plants in the night for 36 hours before starting the 12-12 ratio. Using this approach provides the best plant health and development. 

That said, even if you grow a plant strain using seed obtained from the 12-12 schedule, it might take a few weeks before you get any buds. This is because the photoperiod plant classifies as annual plants. Plants such as cannabis can survive with as little as 8 hours of light per day.

Photosynthesis and Respiration

When green plants are exposed to light, they undergo photosynthesis. This process allows the plants to convert light energy to produce oxygen. The plants in this stage also undergo respiration. Contrary to popular opinion, plants like other aerobic organisms experience respiration regularly. The process stops when they die.

During the dark cycle, plants rest and continue to respire at a constant rate and won’t just respire when you turn off the lights. The Calvin cycle, which is dependent on light, does well to process all the stored up solar energy into carbohydrates. The roots also experience respiration, which makes it vital to growing the plants in well-aerated zones. You can also take advantage of resources such as air pots to keep the plants in an oxygen-rich area.

Floral Cycles and Light Cycles

As an indoor grower, you can also speed up the flowering cycle of your chosen plant by adjusting the amount of light you expose to the plant. Most growers know about the short light cycle methods, which give plants specific times of rest. Each hour that is deducted from the light cycle translates into a reduction in the floral cycle length. This, the plants believe that winter is close, and they need to complete the process as soon as possible. The challenge with this approach is a significant reduction in plant yield.

The other long light cycle approach reduces the length of the light cycle, without compromising the weight of the bud. More so, the best long light cycle category is the 24 on 12 cycles. Using this approach will reduce the flowering cycle of cannabis plants by seven days to a week each month. Thus, a plant that has a normal floral cycle of 60 days can complete the process 14 days early. Also, a plant with a floral cycle of 3 months can complete the process up to 21 days earlier. The tools required to bring the long light cycle is referred to as a programmable timer. It’s a tool that allows the grower to preset on and off cycles, over a specific duration of time. A simple search of the best seven-day timers should bring some interesting plant care results.

There are various as to why this approach is the best. Out of the 170 hours a week of traditional 12 to 12 light cycle, plants will experience an average of 80 hours of light. The more extended 24 on 12 off period offers plants with over 110 hours of light every seven days. When computed in 4 weeks, the plants receive over 510 hours of light, rather than over 350 hours of light. The 150-hour benefit thus means the plant enjoys more than six days added of growth time.


Flowering is perhaps one of the most critical growth stages of any plant. Being able to provide the plant with optimal resources for the flowering stage is, therefore, imperative. To be specific, choosing a proper light cycle for your plant is crucial. There are various types of light cycles, each with its unique benefits for plant development. You will also have to note that different plants respond differently to light cycles.

Aside from light cycles, plants also require various other resources to achieve optimal growth. These other factors include humidity, temperature, ventilation, and more. The light cycle is important because it’s the resource that controls essential procedures such as photosynthesis and respiration.

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