Cannabis Light Cycle Explained - Indoor & Outdoor

Like all plants, cannabis needs light in order to grow. Light gives plants energy, which it uses to create the carbohydrates needed for growth, and a light cycle will determine how much light it will receive per day. That said, your cannabis plant will need different light cycles during its lifetime in order to produce the best yields. So, let’s have a look at what the marijuana light cycle is and how it works. Check out marijuana seeds for sale online. Blue dream seeds, and lemon auto autoflower seed .

Marijuana Light Cycle and the plant stage

Before we talk about the different plant stages and the light cycles for each, we need to discuss how lighting is understood in the grower community. Light cycles are often expressed in the following format: Light Hours/Dark Hours. So, when we talk about a light cycle of 18/6, we’re talking about 18 hours of light followed by six hours of darkness. Likewise, 24/0 would be a light cycle involving 24 hours of lighting with no dark periods.

There are two main stages in the plant’s life that require light cycles: the vegetative stage and the flowering stage. The vegetative stage is where the plant is still growing and is yet to produce any buds. Many growers use an 18/6 light cycle during the vegetative stage, although some prefer 24/0 when growing indoors. In order to begin the flowering process, the plant will need at least 12 hours of darkness. At this stage, you will need to switch to a 12/12 light cycle.

Therefore, the two stages we need to focus on are:

Vegetative Stage – This is where the light cycle is used to ensure the plant growth is as large and robust as possible.
Flowering Stage – This is where the light cycle is used to ensure the plant produces the best yield possible.

We will discuss these stages and their light cycles in depth below.

Vegetative stage – Marijuana Light Cycle 18/6

The vegetative stage of your cannabis plant’s life cycle is where it does all its growing. As such, this is the most important stage when it comes to producing a successful yield. You will notice during this stage that the stems and leaves of your plant are growing larger and taller, however the plant will not produce any buds at this stage.

As your plant continues to grow, you can train its shape and size to your liking. The best way to improve your plant’s growth is by applying the correct light cycle.

Indoor

When it comes to indoor light cycles, there is some debate whether 18/6 or 24/0 is best. Unlike other plants, cannabis does not need any dark periods to complete photosynthesis during its vegetative stage. Therefore, some growers will argue that a 24/0 light cycle will lead to better growth.

Although 24/0 can lead to faster growth, cannabis plants still run according to an internal clock and are generally healthier with some downtime. Plus, a 24/0 light cycle will use more electricity, which will be wasted if the plant is not performing at its best. For this reason, we recommend sticking with an 18/6 light cycle for an indoor crop.

In addition, you will need to consider the size of your plant. Some strains of cannabis such as Jack Herer and Northern Lights can grow especially tall even without training. As such, make sure your grow room has a high ceiling and is well maintained.

Keeping an 18/6 light cycle will ensure your plant remains in its vegetative state for as long as you want. Cannabis needs at least 12 hours of darkness before it can start flowering. Therefore, keep the light cycle at 18/6 until you are satisfied with its growth, after which you can switch to 12/12 to begin the next stage. The length of the vegetative period should last between 4-8 weeks.

Outdoor

Many growers prefer to begin the vegetative process indoors with controlled lighting before moving the plants outside. Usually, they begin growing during early to mid-Spring with an 18/6 or 24/0 light cycle, then move the plants outside in late Spring or early Summer.

The reason for this is because keeping your plants inside at this stage helps protect them from any sudden cold snaps that could kill them. Once the weather is warmer, you can safely move them outside, at which point they will usually remain vegetative up until the end of Summer.