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10 Fastest Growing Cannabis Strains

Seedsman aims to make growing the best cannabis easier, but we can help make it faster, too. Whether you’re late planting your seeds, looking for multiple harvests, or just downright impatient, the easiest way to speed up the whole process is in your choice of cannabis seeds – in other words, by selecting a fast-growing cannabis strain from the outset.

It doesn’t matter if you grow indoors or outdoors, either – if you need results in a hurry, these speedy strains will do the job.

Most of the plants below are hybrids of vigorous photoperiod strain cannabis plants paired with the insanely-quick flowering times of autoflowering strains. Flowering times are somewhat approximate but largely accurate.

Seedsman has a series of fast-growing strains, genetically bred for their turnaround. We’ll have a look at a few of these before examining some classic speedy strains

White Widow FAST

Seedsman’s own White Widow FAST seeds combine the photoperiod genes of the legendary White Widow Strain with Fast genetics. The result is a sturdy plant with a flowering time of between just six and seven weeks, meaning all the most sought-after qualities of the classic 1990s strain can be yours a week sooner than they would with the regular photoperiod version.

Fastest Growing Cannabis

White Widow FAST is a fairly short indica/sativa hybrid, growing to no more than 120cm. This, coupled with its lightning-quick flowering period make it an ideal strain for growers looking to produce with some degree of stealth. She’ll deliver respectable yields, too – look forward to 350-450 gr/m2 of frosty-looking buds, packing a THC content around the 20% mark. This translates to a powerful effect that begins in the head before moving south to relax the body.

White Widow FAST is just as productive and easy to grow indoors, outdoors, or in greenhouses.

Jack Herer FAST

Another classic strain available with a quick finish, Jack Herer FAST somehow manages to improve on the original by shaving up to a fortnight off the flowering time. That’s right – award-winning cannabis can be yours in just seven weeks! Like White Widow FAST, Jack Herer FAST’s growth will peak at no more than 120cm, yielding around 400 gr/m2 of high-THC buds that positively drip with sugary trichomes.

This is a strain well-suited to indoor growing, but outdoor cultivation will produce equally great results, and plants are ready to harvest before the wetter weather comes in around September.

Fastest Growing Cannabis

Jack Herer FAST retains all the desirable qualities of the famed original – expect the unmistakable sweet and peppery Jack taste along with those familiar herbal and pine aromas. It’s a slightly sativa-leaning hybrid with a high-THC content, meaning Jack Herer FAST wraps you in a blissful, euphoric and creative blanket.

C99 x Blueberry FAST

Fans of Cinderella 99 and Blueberry will love the hybrid offspring of these favourites, and the fast-flowering version means you won’t have to wait any more than 7 weeks to get your hands on this fruity beauty.

C99 x Blueberry FAST grows quick, but it also takes a stretch, so be sure to allow adequate room to accommodate the significant growth this indica/sativa hybrid needs when she starts to flower. Equally happy growing indoors or outdoors, this strain produces as much as 450 gr/m2 of high-quality bud, generously coated in trichomes. Cultivators will love to hear that C99 x Blueberry FAST has relatively few larger leaves, and as such, trimming is easy.

Fastest Growing Cannabis

If you like to indulge your palate with fruity flavours, this strain will delight with its combination of blueberry and citrus tastes. Expect more than a hint of South East Asia from its Thai Sativa genetics, and a high THC content of around 20% is yours after just 45 days. C99 x Blueberry FAST will vanish stress and melt your cares away with its dreamy cerebral effects, and in no time at all, you’ll be floating on a wave of euphoria.

Amnesia FAST

For fans of harder-hitting hybrids, Seedsman’s Amnesia FAST has all the qualities you’re looking for in a quick-growing strain. High THC and high yields make for high times with this impressive plant. Ready after 50-55 days of flowering, Amnesia FAST should be on anyone’s shopping list.

Amnesia FAST combines the genetics original Amnesia strain with a top-secret hybrid, and the results are impressive. It’s a medium-sized plant, coming in at 100-150cm, but that plant produces extremely respectable yields of 550-600 gr/m2 when grown indoors. Buds are dense, and generously packed with an eye-popping 25% THC! She’s just as happy growing outdoors, but leave plenty of space when planting to accommodate the additional growth.

Fastest Growing Cannabis

Aroma and taste share some similarities with the original Amnesia strain, but with added fruity and floral notes over and above the spicy haze of its ancestor. The strong cerebral, creative effect from the mostly-sativa genetics, coupled with the outstanding THC content means Amnesia FAST is one you definitely won’t forget!

Black Sugar

For a fast-flowering strain with high yields, high THC and medicinal properties, look no further than Seedsman’s own Black Sugar. In just 8 weeks, this truly unique strain offers up some of the finest traits its parentage has to offer. From Black Domina, we’ve retained the great yield and flowering rate, while keeping the medical properties from L.A. OG and the compact size of the Critical Strain.

Black Sugar is a powerful mostly-indica strain, with a shorter structure that makes it idea for those looking to grow plants quickly with limited space. The yields are among the most impressive around, with 600 gr/m2 common among indoor growers and a superb 800 gr/plant achievable if cultivating outdoors. Buds are generous, and have a sugar-dipped appearance to them

This is a very high-THC strain that offers upwards of 20%, resulting in a powerful, sedative body effect when coupled with the indica properties. For this reason, Black Sugar is an excellent choice as an evening strain to chase away insomnia. A winner with fans of fruity flavours, Black Sugar boasts a taste profile packed full of fruity lemon and orange with a hint of Skunk.

Gorilla Sherbet F1 FAST

Spanish powerhouse Sweet Seeds seed bank brings the heat with Gorilla Sherbet F1 FAST, a high-THC strain bred from Sunset Sherbet and Gorilla Girl XL Auto. The result is a 70% indica strain that can blow your hair back thanks to its THC content, which tops out at around 23%.

This speedy grower is ready in just 49 days and offers up sizeable yields of between 400-550 gr/m2 when cultivated indoors, whereas outdoor growers can look forward to more sizeable plants, and yields between 350-600 gr/plant.

Along with the generous THC levels, expect a mind-bending taste profile that includes sweet citrus, wood, and a hint of cool menthol before being swept away by the happy, relaxing stimulating effect.

Speedy Chile FAST Version

A rapid-flowering, indica-dominant hybrid, Royal Queen Seeds’ Speedy Chile FAST Version combines Green Poison and Chile Indica to stellar effect. This is an easy-growing strain that requires no specific special attention, and the result is an impressive and above-average yield just 8 weeks after germination – that’s two weeks of vegetative, then six weeks of flowering time!

Whether you grow Speedy Chile indoors, outdoors, or under the cover of a greenhouse, you can rest assured you’ll see handsome rewards in a timescale you never would imagine. Yields as high as 500 gr/plant are possible for outdoor cultivators, and indoor growers can look forward to almost the same! It should be noted that Speedy Chile is best grown indoors unless you live in a warmer, Meditteranean-type environment.

Expect a respectable potency from Speedy Chile – THC content is a handsome 16% with very little CBD, resulting in a mellow but uplifting head effect, with some medicinal benefits for insomnia, pain and lack of appetite.

Autoflowering Varieties

2 Fast 2 Vast Auto

If you’re looking for the added ease of Autoflowering properties along with fast flowering times, this one’s worth your attention. Heavyweight Seeds challenged themselves to improve upon their own Fast and Vast strain and did so by adding a Northern Lights Auto to a gene pool comprising White Dwarf and Auto Skunk. The result is a robust plant that gives up its many treasures in just 8 weeks of flowering.

This strain is comfortable growing in any environment and while THC is high at around 20%, makers of extracts and concentrates are sure to be thrilled by the prolific amounts of resin 2 Fast 2 Vast produces – its appearance is positively glistening with crystals. Better yet is the yield – indoor growers can look forward to between 600-800 gr/m2 from this amazingly productive plant.

This is a heavyweight strain from Heavyweight seeds – flavours are fruity to the maximum and a smooth smoke is assured, along with a fantastic, giggly effect that morphs into a long-lasting and relaxed body stone.

Speed Bud Auto

If you’re looking to grow cannabis in record time, you’ll be hard pushed to top Speed Bud Auto for sheer quickness. With a lightning-fast flowering time of just 5 weeks, this small but efficient strain from Female Seeds has few peers when comes to fast-growing cannabis strains.

Touting a diminutive stature of just 80cm, Speed Bud Auto makes a great choice if you’re growing marijuana in a discreet outdoor setting, but is just as comfortable in an indoor environment. Yields are smaller, as you’d imagine, but if sheer flowering speed is what you’re looking for, look no further. As a bonus, this strain is less leafy, meaning manicuring the plant is as quick and easy as growing it!

Speed Bud Auto is a fairly resinous plant but is said to be of lower potency, so if a nice, mellow relaxing effect is your thing, this strain is likely to hit the spot. Enjoy the smooth Diesel taste of this one as you read your speeding ticket!

Star CBD Auto

We wrap up our list of fast-growing cannabis strains with one for the CBD lovers – the Ministry of Cannabis’ Star CBD Auto. Thanks to a rapid flowering time of just six weeks, you can enjoy a strain high in cannabidiol sooner than you may have thought.

Star CBD Auto is a mostly-indica plant, but with a high CBD ratio of about 10% and a low THC ratio to match. The result is a superbly-balanced cannabis strain that offers great therapeutic potential in addition to its recreational capabilities.

Fastest Growing Cannabis

This is a compact plant, but its autoflowering nature and Ruderalis genetics make it robust. An indoor grow can yield up to 120 gr/plant, but outdoor cultivation can see output almost double with some growers reporting yields of 230 gr/plant. Star CBSD Auto’s flavour is described as a blend of incense and musk, with a blissful calming body sensation to soothe aches, pains and stress.

*Please note, in the US we’re running low on the non-Seedsman stock listed above. If the strain you’re looking for is not in stock, don’t stress, we’re currently undertaking a massive stock replenishment in our US warehouse. *

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Duncan Mathers