Photoperiod Cannabis Seeds

What Are Photoperiod Cannabis Seeds?

Photoperiod cannabis plants use changes in the amount of light and darkness they receive as the signal to begin flowering. Indoors, this means you decide when flowering starts by changing the light schedule. Outdoors, the same process happens naturally as the days become shorter towards the end of summer.

This gives photoperiod strains one major advantage: time. Unlike an autoflower, which begins flowering automatically as it reaches a certain age, a photoperiod plant can remain in vegetative growth for longer. That gives you much more control over plant size, training and the structure you develop before moving into flowering.

Why We Still Grow and Breed With Photoperiod Genetics

Autoflowers have become considerably more capable over the years, but photoperiod genetics remain an important part of how we grow, evaluate and develop cannabis strains at MSNL. Having control over the vegetative stage gives us time to observe how a plant develops before flowering, including its growth rate, branching, structure and overall vigour.

Photoperiod plants are also particularly useful for breeding and selection. Keeping plants in vegetative growth gives breeders more flexibility when working with selected genetics, while suitable plants can be maintained as mothers and reproduced through cuttings. For growers interested in breeding themselves, our regular cannabis seeds include male and female photoperiod genetics.

Feminized vs Regular Photoperiod Seeds

Photoperiod describes how a plant flowers rather than whether the seed is feminized or regular, so you'll find both types in our photoperiod collection.

Our feminized seeds are bred to produce female plants, making them the straightforward option when your aim is to grow flower without identifying and removing male plants. Regular photoperiod seeds can produce males or females and are better suited to growers who want access to both sexes for breeding and genetic selection.

How Do You Make Photoperiod Cannabis Plants Flower?

When growing indoors, photoperiod plants are typically kept under longer periods of light during vegetative growth. Once the plants have reached the size and structure you want, switching to 12 hours of light followed by 12 hours of uninterrupted darkness triggers the flowering stage.

The ability to choose when that switch happens is one of the main reasons we recommend photoperiod genetics when control over plant development is important. A smaller grow can be moved into flowering relatively early, while growers with more space can extend the vegetative period and develop larger plants before making the switch.

Photoperiod Seeds vs Autoflower Seeds

The biggest difference is when flowering begins. Photoperiod strains rely on a change in light cycle, whereas autoflower seeds begin flowering automatically according to age.

We wouldn't describe one as better than the other because they suit different types of grow. Autos are useful when speed, compact plants and a simple growing cycle are priorities. Photoperiod strains give you more control over vegetative growth, training and final plant size, and they don't have the same fixed window before flowering begins.

Are Photoperiod Strains Better for Plant Training?

The extra control over vegetative growth makes photoperiod plants particularly well suited to training. Techniques such as topping and low-stress training can temporarily slow growth while a plant recovers, but with a photoperiod strain you can simply keep it in the vegetative stage until you're happy with its structure.

That's different from an autoflower, where the plant continues moving towards flowering regardless of how much training or recovery time it has had. If you want to spend more time shaping a canopy or developing a larger plant before flowering, we'd generally choose photoperiod genetics.

Choosing the Right Photoperiod Cannabis Seeds

Once you've decided that you want the additional control of a photoperiod strain, we'd recommend choosing based on the characteristics that matter most to your grow. Consider available height and space, flowering time, expected yield, difficulty to grow and whether you prefer indica, sativa or hybrid genetics.

We grow and evaluate our genetics for characteristics including plant structure, growth rate, flowering behaviour, consistency and difficulty to grow, and you'll find this information on our individual strain pages. This makes it easier to compare photoperiod strains based on how they grow rather than simply choosing the one with the highest THC percentage or yield figure.

Photoperiod Cannabis Seeds FAQs

What does photoperiod mean in cannabis?

Photoperiod means that flowering is triggered by changes in the amount of light and darkness a cannabis plant receives. Indoors, growers control this by changing the light schedule. Outdoors, flowering begins naturally as daylight hours decrease later in the growing season.

Are photoperiod cannabis seeds feminized?

They can be. Photoperiod refers to the way a plant begins flowering, while feminized and regular describe the sex genetics of the seeds. Our collection includes both feminized photoperiod seeds and regular photoperiod seeds.

How long can you keep a photoperiod plant in the vegetative stage?

Indoors, a photoperiod plant can be kept in vegetative growth for as long as the grower chooses by maintaining an appropriate vegetative light schedule. This gives you considerable control over plant size and allows additional time for training before flowering.

Do photoperiod cannabis plants need 12 hours of darkness?

Indoors, a 12/12 light schedule is commonly used to trigger and maintain flowering in photoperiod cannabis plants. Providing an uninterrupted dark period is important once the plant has been moved into the flowering stage.

Should I choose photoperiod or autoflower seeds?

Choose based on how you want to grow. We'd generally recommend photoperiod seeds when control over plant size, vegetative time and training is important. Autoflowers are better suited to growers who prioritise a faster life cycle, automatic flowering and generally more compact plants.