Autoflowering vs. Photoperiod Cannabis Seeds: What’s the Difference?

When shopping for cannabis seeds, you may see the words feminized, autoflowering, and photoperiod. These terms can be confusing because they don’t all describe the same thing.

Feminized seeds are bred to grow mostly female plants. Autoflowering plants start to flower as they get older, without needing shorter days. Photoperiod plants begin to flower when the days become short enough. Both autoflowering and photoperiod seeds can be feminized [1, 2]

So first ask: Would you prefer an autoflowering plant or a photoperiod plant? Then check whether the seeds are feminized or regular.

What Are Feminized Seeds?

Feminized seeds are bred so that most plants grow female flowers. Growers who want flower buds often choose them because pollen can cause female flowers to produce seeds. Still, feminized seeds aren’t a perfect guarantee. Growers should check their plants as they develop [1].

Feminized seeds can be autoflowering or photoperiod. The word feminized tells you about the plants’ expected sex. It does not tell you when they will flower.

Feminized also does not promise high THC, high CBD, or a large harvest. The plant variety and growing conditions matter too [3].

What Are Photoperiod Plants?

A photoperiod cannabis plant responds to day length. Outdoors, it may start to flower as the days grow shorter. Indoors, growers can change the light schedule to start flowering. The amount of darkness needed can vary by variety [3].

A photoperiod plant can have more time to grow before it flowers. This may give it more time to get larger. However, it does not guarantee a larger harvest.

Growers can also take cuttings from a healthy photoperiod plant. A cutting can grow into a new plant called a clone [1].

What Are Autoflowering Plants?

An autoflowering plant starts to flower as it develops. It does not need shorter days to begin flowering.

Some autoflowering varieties stay small and finish quickly. But size and growing time vary by variety. Check the details for the exact seeds you want rather than expecting every autoflower to grow the same way [4].

Because an autoflower starts flowering on its own, there may be less time for it to grow after an early setback. You can transplant one, but it helps to handle its roots with care.

You can also take a cutting, but the new plant keeps moving toward flowering. This makes cloning less useful for most autoflowers.

Autoflowering does not mean the seeds have a 50/50 chance of growing male or female plants. Autoflowering seeds can be feminized or regular. Check the seed label to see which kind you are buying

Do Autoflowers Have Lower THC or CBD?

You cannot tell how much THC or CBD a plant will have from the word autoflowering alone. Cannabis varieties differ, and growing conditions can affect the results.

One study, for example, found that changing the light schedule affected plant growth and cannabinoid levels in the varieties it tested [3].

Do not assume every autoflower has weaker buds or that every photoperiod plant will produce more. Look at information for the exact varieties you are comparing. Treat listed THC, CBD, and harvest figures as estimates rather than promises.

Bruce Banner: Which Seed Type Is Better?

You may see Bruce Banner on both autoflowering and photoperiod seed listings. Listings may give figures for plant height, THC, CBD, and yield.

Be careful when comparing those numbers. Sellers may offer different versions of Bruce Banner, and plants may be grown under different conditions. A higher number in one listing doesn’t prove one seed type is always better.

The clearest difference is when the plants start to flower. An autoflowering Bruce Banner plant starts flowering as it develops. A photoperiod Bruce Banner plant responds to day length. If either seed pack says feminized, it is bred to grow mostly female plants.

Which Seeds Should You Choose?

An autoflowering variety may suit you if you want a plant that flowers without a change in day length. A photoperiod variety may suit you if you want more control over when flowering begins or want to keep a plant for cuttings.

Before you choose, read the full seed label. Check whether the seeds are autoflowering or photoperiod and feminized or regular. Compare the exact varieties, but remember that no seed label can promise a certain plant size, harvest, or THC level.

Author: Lana Braslavska is a blogger at AskGrowers who writes about cannabis cultivation and cannabis products.