Buy cheap autoflower seeds from $2 per seed: 117 strains, all feminized, whose plants flower on their own without you having to change the light schedule. Most of our autos go from seed to harvest in 9–10 weeks, so outdoors you've got time for more than one harvest a season. Choose packs of 3, 5, 10 or 25 seeds with no minimum order: 23 strains work out to $2 per seed (you'll find them in cheap cannabis seeds). And if you're after autos with CBD, check out our CBD autoflower seeds.
Autoflower seeds are cannabis seeds whose plants switch to flowering with age, 3–4 weeks after germination, without you having to cut back the hours of light. That's why they get from seed to harvest so quickly: most of our autos take 9–10 weeks. The trait comes from Cannabis ruderalis, a subspecies from cold regions with short summers that breeders crossed with indicas and sativas.
All our autoflowering cannabis seeds are feminized too: they give female plants in around 99% of cases, just like photoperiod feminized seeds. What changes is the clock. A photoperiod plant keeps growing as long as it gets long days and only flowers once the light drops to around 12 hours. An auto starts flowering when its time comes, whether it's April or July, under 18 or 20 hours of light.
The first autos were small and not especially potent. Today's are automatic versions of the classics and of modern American genetics, with dense, resinous buds. If you're curious about their history, read our article on autoflowering cannabis.
Go for autoflowers if you want a quick harvest, are short on space or want several outdoor harvests a year. Go for photoperiod feminized seeds if you're after the biggest yield per plant and want to decide for yourself how much it grows before flowering. The underlying difference is what triggers flowering: the plant's age or the hours of light.
| Criterion | Autoflower | Photoperiod feminized |
|---|---|---|
| What triggers flowering | Age: they start flowering at 3–4 weeks | Hours of light: 12/12 indoors; shorter days outdoors |
| Indoor light schedule | 18/6 or 20/4 throughout the cycle | 18/6 in veg and 12/12 in flower |
| Seed to harvest | 9–10 weeks for most of ours | 3–5 months indoors; the whole season outdoors |
| Height | Most stay under 4 ft, according to our product pages | Controllable indoors; big plants outdoors |
| Yield per plant | Lower | Higher |
| Outdoor harvests per year | 2–3 between spring and late summer in areas with long, mild seasons | 1, in the fall |
| Transplanting and pruning | Best avoided: there's no time to recover | No problem during veg |
| Clones and mother plants | Not an option: a clone is as old as its mother and flowers right away | Yes |
| Best for | Speed, discretion, balconies and first grows | Maximum yield and full control over size |
| Price at Bulk Genetics | From $2 per seed | From $2 per seed |
If you want a short cycle but would rather stick with a photoperiod plant, take a look at our fast flowering seeds, which finish earlier than a standard feminized strain. And if you're torn between feminized and regular seeds, our guide to feminized seeds compares all three types.
Most of our autoflowers go from seed to harvest in 9–10 weeks. We checked every product page: of the 117 strains in the catalog, 95 state the full cycle in their description, the median is around 66 days and 74 of them finish in 70 days or less.
| Seed to harvest | Strains |
|---|---|
| 70 days or less | 74 |
| 71 to 84 days | 19 |
| More than 84 days | 2 (Mango Sherbet Auto, 80–100 days, and Mango Haze Auto, 80–90 days) |
In a hurry? These are among the fastest, going by their product pages: Red Devil Auto (around 56 days), Afghan Kush Auto (56–63 days), Purple Punch Auto (60 days), Somango Auto (60–65 days), Biodiesel Auto (60–70 days), Big Bud Auto and Blueberry Auto (65 days). These times are a guide: with too little light, cold temperatures or a small pot, any auto will take a bit longer and yield less.
The key with an auto is that it grows without setbacks during its first 3–4 weeks, because after that there's no time to catch up. Sow it straight into its final pot, give it plenty of light from day one, use a light, airy growing medium, and don't transplant or prune once it's flowering.
Keep the same light schedule for the whole cycle: 18 hours of light and 6 of darkness (18/6) or 20/4. There's no need to switch to 12/12, and with fewer hours of light the plant yields less. As a rough guide, you can fit 6 to 9 plants per 10 square feet in 2- to 3-gallon pots, or 4 to 6 in 4- to 5-gallon pots. Since they all flower on their own, you can keep plants of different ages under the same light and stagger your harvests.
In most of the US you can plant autos from your last frost, somewhere between April and June depending on your area or USDA zone, until July, so they finish before the fall rain and cold set in. With 9–10 week cycles, long warm seasons like those in California, the Southwest or the South allow two or three harvests a year; in the Pacific Northwest, the Northeast or the northern states, expect fewer. Plants started in May and June, which grow through the longest days of the year, usually get the biggest; earlier and later runs stay smaller. In cooler or damp areas, choose early-finishing, mold-resistant strains. For more ideas, see our pick of the best marijuana seeds for outdoors.
Outdoors, use 5- to 7-gallon pots from day one, as we recommend on the product pages of strains like OG Kush Auto. Indoors, 2 to 4 gallons, depending on how many plants you want to fit in. Choose a light, airy growing medium, water without waterlogging and feed at lower doses than you would a photoperiod plant: the plant is smaller and easy to overfeed with nutes.
These are some of our autoflowers with the most character: timeless classics in automatic form, modern American genetics and big XL autos. To choose, check three figures on each product page: the seed-to-harvest time, the maximum height (crucial on balconies and in grow tents) and the aroma.
If you're looking for high-yielding XL or XXL autoflowers to get the most out of every plant, read our pick of the most productive autoflowering strains.
Our autoflower seeds are cheap because we buy and produce them in bulk, in large quantities. Every strain sits in one of three price tiers and, in all of them, the bigger the pack, the less you pay per seed: in tier A, $2 per seed in the 25-seed pack.
| Pack | Tier A (23 strains) | Tier B (24 strains) | Tier C (70 strains) |
|---|---|---|---|
| 3 seeds | $18 ($6.00 / seed) | $26 ($8.67 / seed) | $34 ($11.33 / seed) |
| 5 seeds | $26 ($5.20 / seed) | $38 ($7.60 / seed) | $50 ($10.00 / seed) |
| 10 seeds | $22 ($2.20 / seed) | $66 ($6.60 / seed) | $88 ($8.80 / seed) |
| 25 seeds | $50 ($2.00 / seed) | $150 ($6.00 / seed) | $200 ($8.00 / seed) |
In tier A, the 10 and 25-seed packs are half price (previously $44 and $100). Those 23 autos at $2 per seed are well-known genetics like Blue Dream Auto, Bubblegum Auto, Amnesia Auto, Sour Diesel Auto, Wedding Cake Auto and Pineapple Express Auto, plus several of the featured strains above. You'll find them all together in cheap cannabis seeds.
There's no minimum order, and if you need more seeds you can combine packs: two 25-seed packs give you 50. To work out how many to buy, count the plants that fit in your space, multiply by the number of runs you plan (outdoors, two or three a season where it's warm enough) and allow a margin for the odd seed that doesn't germinate. Curious how our seeds compare with those sold in original breeder packs? We explain it in how our seeds differ from original breeder packs.
Bulk Genetics has been selling seeds since 2016, and its founders have been in the industry since 2001. We ship your autoflower seeds in discreet packaging, free on orders over $99, and they're covered by our germination guarantee.
You can read what other customers say in our reviews and get to know us better on our about us page. Our seeds are sold to adults 21 and over as collectible souvenirs; check your state and local laws before you grow.
Guide reviewed by the Bulk Genetics team. Updated in October 2026.
It means the plant grown from the seed flowers with age, 3–4 weeks after germination, rather than when the hours of light change. It's a trait inherited from Cannabis ruderalis. In practice, you harvest sooner, with no need to switch to 12/12 indoors or wait for fall outdoors.
They're not opposites: all our autoflowers are also feminized, so they give female plants. The difference lies in flowering. Photoperiod feminized plants flower when the light drops to 12 hours and yield more; autos flower on their own and finish sooner. If you're after photoperiod strains, see our feminized seeds.
The seed germinates in 1–5 days. After that, most of our autos are ready in 9–10 weeks: the median across the 95 product pages with the figure is around 66 days. Some are faster, like Afghan Kush Auto (56–63 days), and some slower, like Mango Sherbet Auto (80–100 days).
May and June: the plants grow through the longest days and usually yield more. But you can plant from your last frost, between April and June depending on your USDA zone, until July, and fit two or three harvests into the same season where it's warm, like California or the South, or fewer in the northern states.
Among our product pages with the figure, Red Devil Auto, with a full cycle of around 56 days, Afghan Kush Auto, which can complete it in 56–63 days, and Purple Punch Auto, at around 60 days from germination. Keep in mind that light, temperature and pot size can stretch any cycle.
The bigger ones, like the XL strains: Green Skunk XL Auto, Crystal Bud XL Auto or Devil Jack XL Auto. Even so, yield depends as much on light and pot size as on genetics. There's more in our pick of the most productive autoflowering strains.
Indoors, 18 or 20 hours a day (18/6 or 20/4) for the whole cycle, from germination to harvest. There's no need to switch to 12/12. Outdoors, the more hours of direct sun it gets, the bigger the plant will be.
It's best not to. Sow it straight into its final pot or transplant it only once, before it's two weeks old. If you want to top it, do it in the second or third week; after that, stick to bending and tying down branches.
