A whole host of questions have popped up by future plant parents, with many different types of seeds, lingo and growing methods to explore.

In this article, we will be taking a look at auto-flowering seeds and photoperiodic seeds. Apart from going over the differences between these two seed categories, we’ll also take a look at which type of seed will thrive in what environment. 

The main difference between auto-flowering and photoperiodic plants is the fact that photoperiodic seeds rely on the sun’s seasonal changes to begin flowering whilst auto-flowering seeds can start the flowering process quicker. 

Most photoperiod strains will usually start flowering once they have been exposed to twelve hours of light, mimicking the natural sunlight that plants receive when they’re out in the wild. 

Auto-flowering seeds, on the other hand, do not need to rely on the amount of sunlight or darkness they are exposed to before the flowering process can begin. Once the seed has sprouted a few branches, the plant will then continue to progress independently. 

This means that you can grow auto-flowers indoors under any light cycle you prefer or outdoors all year long but the quality and quantity of your harvest will be affected by the amount of light the autos are exposed to.

Auto-flowers are known for speed. Most auto-flowers take only 2 months to grow from seed to harvest whereas photoperiod strains need at least 4 months to complete their growth cycle. This is one of the reasons beginner planters tend to go for auto-flowers. For example, if you grow a photoperiod strain, it needs at least 8 weeks in the vegetative period to grow to a certain extent.

Photoperiodic seeds usually take around ten to sixteen weeks from seed to harvest whilst auto-flowering seeds on average take anywhere from seven to eleven weeks. 

In simple terms, photoperiodism is the measurement of light the plant is exposed to. When talking about a photoperiod plant, the light and dark the plant is exposed to has to be taken into account.

Photoperiodic cannabis plants will only start flowering once they get at least 12hs of darkness. Photoperiod strains take considerably longer to reach harvest, however, they often produce much larger yields and feature higher levels of cannabinoids.

Here’s a quick recap 

Auto-flowering 

• Do not depend on light to start the flowering stage 
• Ready within 8-9 weeks 
• Average THC levels 22-27%
• An average yield of 450-550 grams per meter square 
• Average size 60-100cm 
• Take up less space 
• The bigger margin of error 
• Great for beginner growers 

Photoperiods 

• Depend on light to start the flowering stage 
• Ready within 10-16 weeks 
• Average THC levels 22-27%
• An average yield of 600-700 grams per meter square
• Average size 80-200cm 
• Take up a lot of space 
• No margin of error 
• Great for experienced growers 

Traditionally, photoperiodic seeds were the only type of strain that growers could find. But, times have changed and auto-flowering seeds are now easier to find on the market. 

Since auto-flowering seeds do not rely on a rigid light schedule to enter the flowering stage, autos are the easier option out of the two when it comes to beginner growers. With auto-flowering seeds, considering light schedules and mimicking an outdoor environment is not needed.

But, with more time photoperiodic seeds are also an option. Although they do take longer to yield results and are trickier to grow, photoperiodic seeds usually have higher THC levels than auto-flowering.

Tag a future plant parent!