How I grow autoflower marijuana plants… (and why )

Blue Mystic Autoflower

A Blue Mystic Auto-flower at 53 days from seed

A few years back, autoflower marijuana plants and seeds got a bad rap as being a waste of time. Much too often, when bloomed they were too small, had no potency, or didn’t bloom at all, etc. Basically a pipe-dream for the average grower, unless you knew a reputable breeder, or someone “connected”.

Today autoflower marijuana strains (auto-flower, auto flower, however you spell it) are very consistent, produce large (3oz+) harvests, and provide PRIMO quality. Autos are starting to catch on in the U.S. and have been very popular with growers in the Netherlands and throughout Europe for some time now.

Grow guide for marijuana beginners.

Why I like autoflower marijuana plants

I like many, have been choosing autoflower marijuana seeds for continuous harvest setups (a.k.a. perpetual harvest). These fast growing marijuana strains, grow from seed to bud within 90 days, and sometimes less, are perfect at supplying high quality medication to patients with minimal growing environments. Unlike traditional continuous harvest setups requiring individual grow rooms for vegetation and bloom, auto-flowering marijuana seeds can be grown AND bloomed in the same space as vegetative plants because the light cycle does not need to be changed. This makes auto-flowering marijuana plants perfect for continuous harvesting or people with very small spaces to grow grass in, as well as blooming in the veg tent – See: Northern Light Autos »

Thick "beer can buds" on our Pro Grow 260 Mod LED, Purple Cheese Autoflower (Plant #1)

Thick “beer can buds” on our Pro Grow 260 Mod LED, Purple Cheese Autoflower (Plant #1)

Also, I recommend choosing feminized auto-flower seeds. Unless you are wanting to start a breeding program, the male plants will just waste time and space. Usually, male autoflower marijuana plants will show themselves within 15 – 20 days, or roughly a week earlier than female plants. Autoflower marijuana seeds grow very well in soil, soil-less (hempy), or hydro.

Harvesting buds - Northern Light Autoflower #1

The aroma is sweet and incense like, and the dense buds have little stem waste. (Northern Light Autoflower)

So how do you grow autoflower seeds and plants?
One of the many cool things about auto-flower marijuana plants, is that they can be bloomed anywhere, even in the Vegetation tent, as they are not dependent of length of the light cycle to induce bloom.

Light cycle: Keep it between 18 – 20 hours of light per day from start to finish.
Don’t jump around, if you begin a 18/6 or 20/4 keep it there for the whole grow.
Running the lights 24/24 is a waste of resources IMHO, and not healthy for the plant (though there are those who dispute this). Over pushing ANYTHING will reach a point of diminishing returns, just as doint the opposite; switching light cycles down to twelve hours will diminish the potential yield of autoflowering marijuana strains.

I like to spread out my germinations by every 3 weeks or so, to stagger my harvests. Often auto-flower seedlings will start off slowly or small, not to worry, as usually by week 3 they declare sex, begin to bloom and it is usually the following week the growth explodes.

The Original Cash Crop: bushy, tasty, frosty!

Soil or soilless: Good drainage is essential. As an example of a commercial soil mix I like would be Fox Farm’s “Happy Frog” potting soil. I’ll add 1 part perlite to 4 or 5 parts potting soil, and wet it with pH’d water + root boosters. If you prefer soilless mixes, again good drainage early on is key.

Auto flower marijuana in the veg tent

Autoflower cannabis blooms alongside vegetative plants at 18/6 lighting

Transplant once, twice at the most… I start my seeds in a 16oz. (.5l) plastic cup with drainage holes in the bottom and my soil mix (For hydro: seed goes into a Coco-coir pellet, or rockwool cube to sprout). After sprouting, wait till they are about a week and a half or so old, you want their roots to be developed to the bottom of the cup. From the cup I go straight to their final pot, usually a 3 gallon smartpot (fabric). I’ve grown autos in 1 gallon pots with good success, but smaller pots will result in smaller yields, IMHO. Smart-pots, air pots, or fabric containers that breathe are best. Remember, a bigger root mass = bigger autoflower plants!

There are several auto-flowering marijuana strains that rival the growth and yield of their non-autoflower siblings. I have personally watched 5 ounces come off one autoflower, that was grown out in under 89 days. Early generations (years past) of autoflower marijuana seeds usually grew no taller than 16 inches, with 12-14 inches the norm. Light intensity, pot size, nutrients all play an important role in determining the size of your marijuana plants at maturity, hence “better the conditions, the bigger the yield” holds true, but genetics hold the true key. Newer strains such as Nirvana’s Northern Light Autoflower easily reach 24 – 36 inches tall with profuse branching & 2oz+ yields.

If you are considering growing a SOG (sea of green) there are many auto-flowering strains perfect for doing so, generally the Auto-flower strains that list plant height as “short” generally make the best  SOGs. Some of the autoflowers listed as “tall”  can exceed 1 meter (3ft) in height.

The Original Cash Crop: bushy, tasty, frosty!

Pro Grow 260 Mod LED, Purple Cheese Autoflower (Plant #1)

Thick “beer can buds” on our Pro Grow 260 Mod LED, Purple Cheese Autoflower (Plant #1)

Should I top, FIM, or LST my Autoflower marijuana plant?
While it is truly amazing, the amount and the speed of growth of a healthy autoflower,  I strongly feel that an autoflower cannabis plant’s lifecycle is already so short that to take away any growth (topping or pruning) will diminish the overall harvest. That said, I have had great success with LST (Low Stress Training – i.e. bending the top & higher branches down low ,to encourage lateral growth), super cropping is another low stress method.

Do auto-flower plants need special fertilizers?
No, any high quality fertilizer can be used.

Assuming you have a rich, nutrient filled (and well draining) soil, you shouldn’t need any early fertilizing. Though, by week 3 (14 days old minimum), I give my auto-flowering marijuana seedlings a light feeding (25% dilution) of a grow type (higher nitrogen) nutrient solution, with micronutrients.

As the auto-flower plants declare sex and pass into full flower, usually about weeks 5 through 6 from seed, I’ll switch to a bloom nutrient regime. I do suggest a little additional nitrogen to go along with a bloom fertilizer regiment (one that contains micro nutrients as well) starting just after the 4th week as autoflowers tend to have rapid, almost violent growth and will need the nitrogen for new growth. I stop adding additional nitrogen at about the 3 – 4th week of bloom.

Whenever using fertilizers & nutrient solutions – Remember that less is better than too much!

Root stimulators (Hormex, Superthrive, ect.) have shown to improve overall plant growth with autoflowers. Healthy roots = happy plants. Given an autoflower’s quick growth it is important to pay extra attention to your plants, study leaf colors, look for early signs of problems, the sooner you catch them, the sooner they are corrected. Depending on the strain, some auto-flowering marijuana seeds grow one main cola, while others are known to develop complex side branching. Harvest yield is dependent on many factors, but the healthier off they start, the better chance they have to finish properly.

Grow Weed Easy!

Northern Light Autoflowers bloom under an L.E.D. grow light.

Auto pilot engage! Northern Light Autos bloom in the Veg Garden.

Are autoflower strains as potent or good as the regulars?
Yes, thanks to the hard work and efforts of many breeders, the quality of the strains are amazing and there are dozens of stable autoflower strains now available. Overall autos are very close to, and some strains just as good as the photoperiod strain (regular). The consensus is autoflower marijuana strains have indeed arrived and they are good to grow!

Nirvana Seed's Short Rider Autoflower

Short Rider Autoflower

Nirvana Short Rider is a hybrid of our discontinued marijuana strains Top 44 and Early Special. Top 44 has long been a trade favourite because of its ability to produce commercially worthwhile amounts of strong, skunky buds in just 44 days of flowering. Even though Early Special itself lacks this characteristic, its Siberian Cannabis Ruderalis genes give Short Rider the unique ability to “autoflower” – to flower independently of light cycles, like lowryder. This means you won’t need to maintain a strict lighting schedule for these marijuana seeds – they will flower regardless! These seeds are a must for cannabis growers with limited space or who simply want to finish extra early. The quality of the weed is amazing considering how little time it takes these marijuana seeds to finish. Short Rider Auto Flower »

Northern Light Autoflower

Northern Light Autoflower

Nirvana Northern Light auto-flower is a marijuana strain which is highly suited to indoor growing. Of course, this auto-flowering version is also perfect for outdoors. Nearly all promising modern indoor cannabis strains contain Northern Light genes. With its high flower-to-leaf ratio, compact buds, good yields and exceptional resin production, these wonderful marijuana seeds are a most lucrative choice for the professional cannabis grower. The smoke’s flavour is somewhat neutral, yet full-bodied. Northern Light Auto Flower »

Jock Horror Autoflower

Jock Horror Autoflower

Jock Horror is a three-way marijuana hybrid of Northern Light, Skunk and Haze. Jock produces so much resin that even its branches glisten with THC glands. This marijuana variety has a unique fresh flavour and packs a strong “up” buzz. Our Jock seeds will finish flowering earlier than the original Jack of a few years ago. One of our all-time favourite marijuana seeds. Jock Horror Auto Flower »



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