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light cycle for flowering cannabis

Best Light Schedule For Cannabis In The Flowering Stage

The majority of cannabis plants are photoperiodic, this means they depend on a 12/12 light cycle to flower. It’s crucial you provide the correct light cycle so your plants start to flower, although depending on the strain this can change, autoflowering strains start flowering automatically and don’t depend on light.

Cannabis plants in the flowering stage have already grown their branches and main cola, and are ready to put on weight in the form of buds.

Failing to provide them a good amount of light in this stage will result in airy buds, low yields, and your plant can become weak and unhealthy.

1. What Is The Light Cycle In Flowering Cannabis?

In the flowering stage, the amount of light your cannabis plants receive will influence on the quality, density, and yield of the buds. This means the buds will produce more resin and grow denser the more light they receive, resulting in a higher yield.

The most common light cycle for the flowering stage is 12/12.

This is because cannabis starts flowering when they receive at least 12hrs of darkness, while still needing the maximum amount of light possible to produce buds.

Our days only have 24hrs, so after 12hrs of darkness, the maximum hours of light we can give them is 12hrs.

There is no other light cycle to flower cannabis as they need as much light as possible, giving them less than 12hrs per day will result in lower quality and yield.

2. Light Cycle For Flowering Cannabis Outdoor

Photoperiodic Plants

When flowering outdoors, you have to be really careful and plan ahead. As you may know, every season has a different light cycle and this will determine how long your plant grows before starting to flower.

To give you an example, cannabis outdoors in California only flowers from September to March. So if you were to cultivate a cannabis plant starting in April it would grow for 5 months before starting to flower, in September, resulting in a huge plant.

If you want to avoid this, you can apply light deprivation techniques, this consists of using a black tarp to prevent light from reaching your plants.

This is used by all farmers, independent of the kind of plant they’re growing, the downside is you will need a greenhouse to be able to do this, as you need to block all light from coming in and this can be really hard to achieve without a structure to firmly hold the tarp.

Autoflowering Plants

With autoflowers you won’t have any of these problems. Autoflowering cannabis doesn’t need a vegetative stage per se, it will grow and flower depending on age.

This means it’s way easier to grow them than photoperiodic plants. A really good tip is to search on the internet the amount of light you will get on each month and plan your harvest accordingly, your plants can benefit from the extra hours of light.

Even though autoflowering cannabis can flower properly all year long, it can slightly improve the quality and yield of your harvest.

3. Light Cycle For Flowering Cannabis Indoors

Photoperiodic Plants

As said above, photoperiodic plants flower in a 12/12 light cycle. When growing indoors we keep it the same, although it can be easier to flower indoors because you don’t have to plan ahead.

When you feel like your plants have grown enough, you can simply change the light cycle from 18/6 to 12/12 by adjusting your timer.

It can take a couple of weeks for your plants to enter the pre-flowering stage and show signs of maturity (pistils or pollen sacs if they’re regular seeds), but soon you’ll see beautiful buds forming.

Autoflowering Plants

For autoflowering plants, there’s actually not much to do. They flower from seed in a vegetative light cycle, by providing an 18/6 light cycle from seed, your plants will go through all their cycle: seedling, vegetative and flowering without having to change anything other than the nutrients mix (if it’s required).

If you’re wondering why this happens, it is because automatic cannabis is a hybrid cross between Ruderalis and Indica or/and Sativa.

By crossing with Ruderalis, cannabis strains can have its characteristic of automatic flowering.

4. In Conclusion

Just like in the vegetative stage, when in the flowering stage your plants need the proper amount of light if you want your plant to develop to its maximum. If they don’t get the amount of light they need while flowering, the buds won’t develop properly and won’t produce the maximum amount of trichomes they can, resulting in lower yields and buds with less quality.

Your plants can also get weak and have a higher chance of being attacked by pests or diseases. To avoid this, always plan ahead when growing outdoors and get informed of how the seasons are in your city, including not only the amount of light but also humidity and temperature.

If you’re growing indoors, be sure to provide a good growing environment and especially a good amount of light and the correct light cycle.

The majority of cannabis plants are photoperiodic, this means they depend on a 12/12 light cycle to flower. It’s crucial you provide the correct light cycle so

Cannabis Light Schedules: Vegetative Stage vs Flowering Stage

Cannabis plants keep getting bigger and bigger with long days, and start making buds when you give them long nights.

Cannabis is a “photoperiod” plant, which means the amount of light received each day decides when the plant starts flowering or making buds. This article explains how much light a day your photoperiod cannabis plants need to grow and start budding, so you get to a happy harvest day. What about auto-flowering strains?

Vegetative – Seedling or clone leads to Vegetative Stage –
Give 18-24 hours of light a day

Flowering – Flowering (Budding) Stage leads to Harvest –
Give 12 hours light & 12 hours dark each day

Seedling or Clone

While not technically a “stage,” all grows start with cannabis seeds or clones.

Indoors

Plant your seeds or clones when you’re ready to start growing! What are clones? https://www.growweedeasy.com/cloning

Outdoors

Some outdoor growers start their plants indoors to give them a headstart before putting plants outside.

If you’re growing cannabis outdoors with seeds, you should wait until a few weeks after the spring equinox to put your seeds outside. In the northern hemisphere this means seeds go outside in-or-after April, In the southern hemisphere seeds go outside in-or-after October.

For growers starting with cannabis clones, generally you should wait a few weeks longer than with seeds. Cannabis clones are more prone to flowering early outdoors than seeds, so you might want to put your clones out in late Spring or early Summer. (What are clones?)

If you live in a cold climate, you must also wait until after the last frost before putting your plants outside. Freezing temps will kill cannabis plants. Strain choice is very important. Some strains flower earlier than others. For outdoor growers in cold climates, it’s important to make sure you grow a strain that is matched up with your local weather, so that plants are ready for harvest before temperatures drop.

Vegetative Stage

The vegetative stage is one of the most important parts of the life of your cannabis plant.

The vegetative stage is the growing stage of the plant. When in veg, cannabis plants grow bigger and taller, growing only stems and leaves. As a grower, you are able to control the size and shape of your plants in the vegetative stage using simple training methods.

During the entire vegetative stage the plant does not produce buds at all. It only grows stems and leaves. During the vegetative stage plants tend to grow very fast, especially when conditions are right.

What keeps cannabis in the vegetative stage?

Short nights keep cannabis plants in the vegetative stage. You can keep a cannabis plant in the vegetative stage for basically forever as long as the plant continues to get short nights (shorter than 1s-12 hours, depending on the strain).

Cannabis will stay in the vegetative stage as long as the plant gets short nights (less than 11-12 hours of darkness each day)

Whether you’re growing indoors or outdoors, you must make sure your cannabis plants get at least 13 hours of light each day to stay in the vegetative stage. If your plant gets a few long nights, it may start budding before you want.

The plant can receive as much as 24 hours of light a day while in the vegetative stage. Many indoor growers provide 18-24 hours of light a day (known as 18-6 or 24-0 light schedules) during the vegetative stage to encourage faster vegetative growth.

Don’t want to worry about light schedules? For growers that don’t want to pay attention to light schedules, there are auto-flowering strains of cannabis, which will automatically go through their whole life in about 3 months no matter what light schedule is provided. For some growers, an auto-flowering strain may be more simple than a traditional (photoperiod) strain.

Indoors

Most indoor growers provide 18-24 hours of light a day (known as 18-6 or 24-0 light schedules). Giving your cannabis plants more hours of light each day in the flowering stage will encourage faster growth.

Lingo: When a grower provides 18 hours of light a day and 6 hours of darkness, this is commonly known as the 18/6 light schedule. For 24 hours a day, this is referred to as the 24-0 light schedule.

Outdoors

As long as your plant is getting plenty of light a day, your plant will automatically stay in the vegetative stage from late spring until late summer. Every strain is a bit different.

Flowering Stage

Cannabis starts budding when plants get at least 12 hours of uninterrupted darkness each night. After plants start budding, they must continue to get long dark nights until harvest or they may revert back to the vegetative stage.

Indoors

Indoors most growers put their plants on a 12-12 schedule to initiate flowering. Outdoors the plant will naturally start budding in late summer when nights are growing longer and longer as winter approaches. Just make sure plants aren’t exposed to light during their dark period!

What is 12-12 Lighting?

The indoor grower will need to artificially induce flowering/budding in plants by changing the light schedule so the plant receives only 12 hours of light a day, and 12 hours of uninterrupted darkness.

Once the plant is changed over to the flowering (12/12) light schedule, there is generally another 6 weeks-5 months (average 2.5 months) before the plant’s buds are ready for harvest.

Outdoors

Outdoor growers wait until their cannabis plants start naturally flowering on their own, usually after mid-summer when days start getting shorter than 12 hours.

It’s important to make sure plants aren’t exposed to light at night during their dark period, even street lights or spotlights, as this can prevent cannabis plants from flowering properly.

Growing Indoors? Not Sure When To Switch To Flowering?

So indoor growers have a choice to flower their plants whenever they want… When is the best t ime to start flowering your cannabis indoors?

The real answer is that it’s a matter of personal preference and also depends on what end result you’re looking for. There are two major considerations when choosing the right time to switch to 12/12, the age of the plant and the height of the plant:

Age: Some growers feel that a marijuana plant which has been grown from seed will not produce as many buds or have enough resin production if the plant is not given at least 60 days in the vegetative stage to mature before it’s changed over to the flowering stage. This is not true. many growers initiate flowering soon after germinating a seed in order to keep plants small and short. This is often called “12-12 from seed.” Just remember, no matter what you do, a young cannabis plant will not start flowering until it is 2-3 weeks old. Even if you put a seed on a 12-12 schedule from the beginning, it will not start properly budding for about 3 weeks. When growing with cannabis clones, age is not an issue and growers can switch directly to flowering once your clone has established roots. This is because even though a clone may be small, it’s still a ‘mature’ plant since it is made of a piece from a mature plant. Rooted clones tend to grow much faster for the first few weeks than plants grown from seed. In any case, age is not much of an issue, and you should switch your light schedule at the time that best fits your needs.

Height: A general rule is that your marijuana plant will double or triple in size during the flowering stage from the point where you first change over the light schedule to 12/12. Some plants will grow more, some will grow less, but a good rule of thumb is to change your light schedule over to flowering when your plants have reached half of their final desired height. Bending, known as “LST” or “low stress training” can be used to control colas that get too tall. Simply bend too-tall colas down and away from the center of the plant. Some growers will even slightly break or “supercrop” branches to get them to bend at a 90 degree angle. For those growing in a small space, height may be the primary concern. However, there are many techniques available to grow a short, bushy weed plant or basically train your cannabis plant to grow into any shape you want.

Here’s an example of LST to keep a plant short:

In optimal conditions if height and space is not an issue, you would probably want to vegetate your cannabis plant for 60 days or more before switching it over to flowering. This gives your plant plenty of time to grow big (so you get bigger yields), and allows new growers to dial in their grow before plants enter the sensitive flowering stage. In the vegetative stage, it is easy to recover from problems, but problems are a lot more serious in the flowering stage, where mistakes can dramatically hurt your final yields.

Giving cannabis plants more time in the vegetative stage, and taking time to train them to fit your space, will give you the best final yields. However, if space is tight, then it’s better to switch when the plant is half the final desired height, or even to just attempt to flower your cannabis plant straight from seed.

Harvest!

After the vegetative and flowering stage are over, it is time to harvest your plants!

What do I need to know about light cycles and flowering my marijuana plants? Plants keep getting bigger and bigger with long days, and start making buds when you give them long nights.