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What’s the Difference Between Autoflower and Photoperiod Seeds?

What’s the Difference Between Autoflower and Photoperiod Seeds?

by | Jan 2, 2026 | Growing guides

Quick Answer: What You Need to Know

🌱 Autoflower seeds flower automatically after 3-4 weeks, regardless of light schedule

🕐 Photoperiod seeds only flower when you change the light cycle to 12/12

⏱️ Autoflowers finish in 8-12 weeks total; photoperiods take 3-5 months

📏 Autoflowers stay smaller (60-100cm); photoperiods grow larger (100-200cm+)

🎯 Autoflowers = speed and simplicity; photoperiods = control and yield

If you’re choosing between seed types, start here: our complete range of cannabis seeds in Australia.

Side by side comparison of autoflower and photoperiod cannabis plants showing size and growth differences

The Fundamental Difference: Light Dependency

The core difference between autoflower and photoperiod cannabis seeds comes down to one thing: how they decide when to flower.

Photoperiod plants are light-sensitive. In nature, they flower when days get shorter (late summer/autumn). Indoors, you control this by switching from 18/6 light to 12/12 light. Until you make that change, they stay in vegetative growth.

Autoflower plants ignore light schedules entirely. They flower based on age—typically 3-4 weeks after sprouting, no matter what light cycle you’re running. This trait comes from Cannabis ruderalis genetics, a subspecies that evolved in regions with short summers where waiting for shorter days would mean missing the growing season entirely.

I’ve tested hundreds of autoflower and photoperiod strains over the years, and this genetic difference creates a cascade of practical differences that affect everything from grow time to final yield.

The Genetic Marvel: How Autoflowers Were Created

Autoflower cannabis is one of the most impressive breeding achievements in modern horticulture. Here’s the fascinating story:

Enter Cannabis ruderalis – a wild subspecies that evolved in the harsh climates of Siberia, northern Russia, and Central Asia. Unlike Cannabis indica and Cannabis sativa (which evolved near the equator with consistent day/night cycles), ruderalis developed in regions with extreme seasonal variation.

In these short-summer environments, waiting for autumn’s shorter days would be fatal—plants would freeze before flowering. So ruderalis evolved a survival mechanism: age-based flowering. After 3-4 weeks of growth, ruderalis automatically flowers regardless of light schedule, ensuring it completes its lifecycle before winter arrives.

The problem? Wild ruderalis is tiny, low-potency, and produces minimal flowers. Not exactly what collectors want.

The breakthrough came in the 1970s-80s when breeders realized they could cross ruderalis with elite indica and sativa strains. Through careful selection over multiple generations, they created plants that:

✨ Retained the auto-flowering trait from ruderalis

✨ Gained potency, flavor, and yield from indica/sativa parents

✨ Stabilized genetics so the auto trait breeds true

Early autoflowers (2000s) were weak—maybe 8-12% THC with mediocre yields. But modern autoflowers from quality breeders now regularly hit 20-25% THC with respectable yields, all while finishing in 10 weeks. That’s decades of selective breeding compressed into plants that combine the best of three cannabis subspecies.

It’s genuinely remarkable: You’re growing plants that carry ancient survival genetics from Siberian ruderalis, wrapped in the potency and terpenes of California or Amsterdam elite strains. Every single gorilla glue autoflower seed, for example, represents thousands of hours of breeding work to perfect that genetic balance.

What Are Autoflower Seeds?

Autoflower seeds produce plants that automatically transition from vegetative growth to flowering based on age, not light cycle.

Key Characteristics:

⏱️ Fast lifecycle: 8-12 weeks seed to harvest

📏 Compact size: Usually 60-100cm tall

🌞 Light flexible: Can run 18/6 or even 20/4 throughout entire grow

🔄 No re-veg risk: Once flowering starts, it’s committed

🚀 Beginner-friendly: Simpler light management

📦 Lower yields: Typically 30-80g per plant

Best for:

✓ First-time growers

✓ Limited space

✓ Quick turnaround

✓ Outdoor grows in short seasons

✓ Perpetual harvests (stagger planting)

At Sacred Seeds, our most popular autoflowers finish in 9-11 weeks with minimal fuss. They’re forgiving of beginner mistakes and don’t require light schedule changes.

What Are Photoperiod Seeds?

Photoperiod seeds produce plants that flower only when exposed to 12 hours of darkness per day.

Key Characteristics:

🕐 Light-dependent: Need 12/12 light cycle to flower

📏 Larger plants: Can grow 100-200cm+ depending on veg time

⏳ Longer lifecycle: 3-5 months total (you control veg length)

🌿 Bigger yields: 100-300g+ per plant possible

🔬 More control: Extend veg time, take clones, train heavily

🎨 Full genetic expression: Terpenes and potency often more pronounced

Best for:

✓ Experienced growers

✓ Maximizing yield

✓ Taking clones (autoflowers can’t be cloned effectively)

✓ Training techniques (topping, mainlining, SCROG)

✓ Outdoor grows in full summer season

Photoperiods give you complete control over plant size. Want a small plant? Veg for 2 weeks. Want a massive plant? Veg for 8 weeks. This flexibility is why experienced growers often prefer them.

Side-by-Side Comparison

Growing Time

🟢 Autoflower: 8-12 weeks total

🔵 Photoperiod: 12-20 weeks total (depending on veg time)

Plant Size

🟢 Autoflower: 60-100cm (compact)

🔵 Photoperiod: 100-200cm+ (you control size)

Yield Per Plant

🟢 Autoflower: 30-80g typical

🔵 Photoperiod: 100-300g+ possible

Light Schedule

🟢 Autoflower: Any schedule works (18/6, 20/4, even 24/0)

🔵 Photoperiod: 18/6 for veg, must switch to 12/12 for flower

Difficulty Level

🟢 Autoflower: Beginner-friendly

🔵 Photoperiod: Requires more knowledge

Training Tolerance

🟢 Autoflower: Limited (no time to recover from stress)

🔵 Photoperiod: Excellent (can extend veg to recover)

Cloning Ability

🟢 Autoflower: Not practical

🔵 Photoperiod: Easy to clone

Outdoor Suitability

🟢 Autoflower: Multiple harvests per season possible

🔵 Photoperiod: One harvest per season (follows natural light)

Which Should You Choose?

Choose Autoflowers if you want:

✓ Fast results (first harvest in 10 weeks)

✓ Simple growing (no light schedule changes)

✓ Compact plants (balcony, small tent)

✓ Multiple harvests per year outdoors

✓ Forgiving genetics for beginners

Choose Photoperiods if you want:

✓ Maximum yield per plant

✓ Full control over plant size

✓ Ability to take clones

✓ Advanced training techniques

✓ Peak terpene and cannabinoid expression

My take: Neither is “better”—they serve different purposes. I recommend new collectors start with autoflowers to build confidence, then experiment with photoperiods once they understand the basics. Many experienced growers run both: autos for quick harvests, photos for their main crop.

Browse our full range of autoflower and check out all our feminised photoperiod seeds to find what suits your growing style.

Frequently Asked Questions

Are autoflowers less potent than photoperiods?

No, modern autoflowers can match photoperiod potency. Early autoflowers (2000s) were weaker, but today’s genetics from quality breeders regularly test at 20%+ THC. The main difference is yield size, not potency. Top-shelf autoflowers from reputable breeders deliver the same quality as photoperiods in a smaller, faster package.

Can you clone autoflower plants?

Technically yes, but it’s not practical. Autoflower clones continue aging from the mother plant’s age, so they flower almost immediately with minimal growth. You’d get a tiny plant with negligible yield. Photoperiods clone perfectly because you can keep them in vegetative growth indefinitely. If you want to preserve genetics, photoperiods are the only practical option.

Do autoflowers need 24 hours of light?

No, autoflowers don’t need 24-hour light, though some growers use it. Most run 18/6 or 20/4 for the entire grow. While autoflowers will flower under any light schedule, they still need some rest period for optimal growth. 18/6 is the sweet spot—enough light for good growth without stressing the plant or wasting electricity.

Which yields more: autoflower or photoperiod?

Photoperiods yield significantly more per plant—typically 100-300g+ vs 30-80g for autoflowers. However, autoflowers finish faster, so you can run 2-3 auto cycles in the time one photoperiod takes. For small spaces, autos can actually produce more total yield per year despite smaller individual harvests.

Can you grow autoflowers outdoors in Australia?

Yes, autoflowers excel outdoors in Australia. Unlike photoperiods that follow seasonal light changes, autos can be planted spring through autumn for multiple harvests. In warmer regions, you can get 3-4 auto harvests per year. They’re also less conspicuous due to smaller size and faster finish time.

What happens if you give autoflowers 12/12 light?

Autoflowers will still flower on 12/12 light, but yield suffers because they receive less total light energy. They don’t need 12/12 to trigger flowering—they flower automatically regardless. Running autos on 12/12 wastes their potential. Stick with 18/6 or 20/4 for best results.

Are feminised seeds autoflower or photoperiod?

Feminised seeds can be either autoflower or photoperiod. “Feminised” means the seeds produce female plants (no males). “Autoflower” vs “photoperiod” refers to flowering behavior. You can get feminised autoflowers, feminised photoperiods, regular autoflowers, or regular photoperiods. Check the seed description to know which type you’re getting.

Can you switch autoflowers to 12/12 mid-grow?

You can, but there’s no benefit and it reduces yield. Autoflowers don’t need light schedule changes to flower—they do it automatically. Switching to 12/12 just gives them less light energy, resulting in smaller plants and lower yields. Keep autos on 18/6 or 20/4 throughout their entire lifecycle.

What Are Feminised Cannabis Seeds?

What Are Feminised Cannabis Seeds?

by | Dec 26, 2025 | Growing guides

Quick Answer: What You Need to Know

🌸 Feminised seeds produce female plants 99.9% of the time

🚫 No males means no wasted space or accidental pollination

🎯 Efficiency – every seed you plant becomes a flowering plant

🧬 Breeding technique uses stress or silver solutions to create female pollen

✅ Industry standard – most collectors choose feminised over regular seeds

Building your collection? Check out our full cannabis seed range, ready to dispatch Australia wide..

Healthy female cannabis plant with dense flower buds from feminised seeds

Understanding Feminised Cannabis Seeds

Feminised cannabis seeds are bred to produce only female plants—the ones that develop the resinous flowers collectors want. In regular (non-feminised) seeds, you get roughly 50/50 male and female plants, which means half your seeds produce males, and you must identify and remove them.

For most collectors, males serve no purpose. They don’t produce significant flowers, and if left near females, they’ll pollinate them—turning your flowering plants into seed factories instead of resin producers. Feminised seeds eliminate this problem entirely.

The practical benefit is simple: Plant 5 feminised seeds, get 5 female plants. Plant 5 regular seeds, get approximately 2-3 females and 2-3 males you’ll discard. For collectors with limited space or plant counts, feminised seeds make perfect sense.

I’ve tested thousands of feminised seeds from quality breeders, and hermaphrodite rates (plants showing both male and female flowers) are typically under 1% when grown properly. The technology has been refined over 20+ years to the point where feminised seeds are now the industry standard.

How Are Feminised Seeds Made?

Breeders create feminised seeds by inducing a female plant to produce viable pollen, then using that pollen to fertilise another female. Because both parents are XX, the offspring express female genetics in 99%+ of cases.

Common methods:

⚗️ Silver thiosulfate (STS): The professional standard. A precise silver-based spray temporarily suppresses ethylene signalling so the plant forms pollen sacs. STS is consistent, needs fewer applications, and produces stable, reliable feminised pollen when used correctly.

🔬 Colloidal silver: Effective for hobby use but requires daily spraying and is less consistent than STS.

🌿 Rodelization (stress pollen): Leaving a female to over-ripen can trigger a few male flowers. It’s largely outdated because it can pass on intersex tendencies.

At Sacred Seeds we only stock lines from breeders with documented feminisation protocols and stability testing (multi-site test runs, intersex tracking, and batch-level germination). That’s how we keep real-world hermaphrodite rates well under 1% when grown in stable conditions.

We store all lots in climate-controlled conditions (~6–8°C, 30–40% RH) and batch-test them before release; we also retest long-stored lots every six months.

Benefits of Feminised Seeds

✅ No Male Removal

You don’t need to identify and remove males during early flowering. Every plant you grow reaches harvest.

✅ Space Efficiency

Small grow spaces benefit hugely. If you can only grow 4 plants, you want all 4 to be female.

✅ Simplified Growing

Beginners don’t need to learn male/female identification. Plant, grow, harvest—it’s that simple.

✅ Consistent Results

You know exactly how many flowering plants you’ll have. No surprises, no wasted resources.

✅ Better for Autoflowers

Since autoflowers can’t be cloned, feminised autos ensure you get females every time without wasting fast-finishing plants on males.

✅ Preserves Rare Genetics

If you’ve sourced a hard-to-find strain, feminised seeds ensure you get a female to work with.

When Feminised Seeds Aren’t Ideal:

❌ Breeding classic male/female lines: You’ll need regular seeds to select true males

❌ Slight cost premium: Feminised lines are pricier due to the extra work; value evens out because every seed becomes a female

❌ Low-quality sources can herm: The real risk comes from cheap, poorly stabilised lines—stick to proven breeders and avoid grow stress (light leaks, heat swings)

Feminised vs Regular Seeds: Which to Choose?

Choose Feminised Seeds if:

✓ You want guaranteed female plants

✓ You have limited growing space

✓ You’re a beginner

✓ You’re growing autoflowers

✓ You don’t plan to breed your own seeds

✓ You want maximum efficiency

Choose Regular Seeds if:

✓ You want to breed your own strains

✓ You’re hunting for unique phenotypes

✓ You want to create mother plants for cloning (though feminised works fine for this too)

✓ You prefer traditional, unmanipulated genetics

My take: For 95% of collectors, feminised seeds are the smarter choice. They eliminate the male/female guessing game and ensure every seed produces a flowering plant. Regular seeds have their place in breeding projects, but for personal collections, feminised seeds simply make more sense.

Common Myths About Feminised Seeds

❌ Myth: Feminised seeds are less potent

Truth: Potency comes from genetics, not feminisation. Feminised seeds from quality breeders match or exceed regular seed potency.

❌ Myth: Feminised seeds produce hermaphrodites

Truth: Hermaphrodites come from genetics or stress, not feminisation. Quality feminised seeds have <1% hermaphrodite rates.

❌ Myth: You can’t clone feminised plants

Truth: Feminised plants clone perfectly. The feminisation process doesn’t affect cloning ability at all.

❌ Myth: Feminised seeds are “unnatural”

Truth: The technique mimics natural stress responses. Cannabis plants naturally produce some male flowers under stress—breeders just control this process.

❌ Myth: Feminised seeds don’t germinate as well

Truth: Germination rates depend on seed freshness and storage, not feminisation. Our feminised seeds show 95%+ germination rates.

Are Feminised Seeds Right for You?

Feminised seeds are ideal if you:

🎯 Want every seed to produce a flowering plant

🎯 Have limited space (balcony, small tent, strict plant limits)

🎯 Are new to growing and want simplicity

🎯 Don’t plan to breed your own strains

🎯 Want to maximize efficiency and minimize waste

The bottom line: Unless you’re specifically breeding or prefer traditional methods, feminised seeds offer clear advantages with no real downsides. They’ve become the industry standard for good reason—they work.

Browse our full range of feminised cannabis seeds from some of California, Oregon, and Amsterdam’s top breeders.

Frequently Asked Questions

Can feminised seeds produce male plants?

Feminised seeds produce female plants 99%+ of the time. True males from feminised seeds are extremely rare (under 0.1%). Occasionally, stressed plants may show a few male flowers (hermaphrodites), but this is usually due to environmental stress, not the seeds themselves. Quality feminised seeds from reputable breeders are highly reliable.

Are feminised seeds more expensive than regular seeds?

Yes, feminised seeds typically cost 20-40% more than regular seeds because of the extra breeding work required. However, they’re more cost-effective overall since every seed produces a usable plant. With regular seeds, you’re paying for males you’ll discard, making feminised seeds better value despite higher upfront cost.

Can you breed with feminised seeds?

Yes, you can breed with feminised seeds. Feminised plants can be used as mothers or pollen donors (using colloidal silver). However, breeding two feminised plants will only produce feminised offspring—you won’t get regular seeds. For traditional breeding with males, you need regular seeds.

Do feminised seeds take longer to grow?

No, feminised seeds grow at the same speed as regular seeds. Growth time depends on whether they’re autoflower or photoperiod, not whether they’re feminised. A feminised autoflower finishes in 8-12 weeks; a feminised photoperiod takes 3-5 months—same as their regular seed counterparts.

Will feminised seeds hermaphrodite?

Quality feminised seeds from stable genetics rarely hermaphrodite (<1% rate). Hermaphrodites usually result from stress (light leaks, temperature extremes, physical damage) or poor genetics, not from feminisation itself. Avoid stress and buy from reputable breeders to minimize hermaphrodite risk.

Can you clone feminised plants?

Yes, feminised plants clone perfectly. There’s no difference in cloning ability between feminised and regular plants. You can take cuttings from feminised plants and create identical copies just as easily as with regular seeds. The feminisation process doesn’t affect cloning at all.

Are all autoflower seeds feminised?

No, but most are. Autoflower seeds can be feminised or regular, though feminised autoflowers are far more common because they make more sense—you can’t clone autos, so getting guaranteed females is essential. Always check the seed description to confirm whether autoflowers are feminised or regular.

Do feminised seeds need special growing conditions?

No, feminised seeds grow under the same conditions as regular seeds. They need the same temperature, humidity, light, and nutrients. The only difference is the outcome—feminised seeds produce females. Growing requirements are identical to regular seeds.