How Long Do Autoflowers Take From Seed To Harvest?

How long autos take to flower, brief overview of their lifecycle, harvest window & what to consider
21 April 2020
7 min read
How Long Do Autoflowers Take From Seed To Harvest?

  • 1. The life cycle of autos
  • 1. a. Week 1
  • 1. b. Week 2
  • 1. c. Week 3
  • 1. d. Week 4
  • 1. e. Week 5
  • 1. f. Week 6
  • 1. g. Week 7
  • 1. h. Week 8
  • 1. i. Week 9
  • 1. j. Week 10
  • 2. The advantages of growing autos
  • 3. In conclusion

Autoflowering cultivars changed the way that Cannabis could be grown indoors or outdoors, without being dependent on specific light cycles. From seed until the point of harvest, autos will begin to flower despite the various seasons during the year, making these low maintenance and highly resistant plants a grower’s best friend. So, if you're wondering how long does it take for weed plants to grow ? In this article we explain what to consider when growing autos, the benefits associated, the life cycle broken down week by week including our grow tips.

1. The Life Cycle Of Autos

The following guide is based on an autoflowering cultivar that takes 10 weeks from seed until harvest.

Week 1

During the earliest stages of growth, the seedling will only grow as tall as one inch, producing its first set of leaves. By this time, the tap root of the seedling will grow downwards anchoring itself to the base of the pot. If grown in soil, seedlings can be fed plain water or a mild nutrient solution root booster.

•  Grow Tip: The first week is a very delicate time and seedlings should be given extra care and attention, especially if planting directly outside in a hot or cold climate.

How Long Do Autoflowers Take From Seed To Harvest?: Lifecycle of your cannabis plant

Lifecycle of your cannabis plant: 3-4 weeks - vegetative stage; after 4 weeks - flowering stage

Week 2

After 7 days the seedlings will begin to grow taller increasing the size of the fan leaves. During this time the plants are in a vegetative state so they will rely on Nitrogen, Phosphorus, and Potassium as well as trace elements to aid in foliar development, stem production and root production.

•  Grow Tip: Organic soil will have all of the primary nutrients and trace elements a Cannabis plant requires during the early stages. Bottled nutrients will also work well as long as you follow the recommended guide.

Week 3

By week 3, the plants will have grown tall quickly, with shoots between the internodes, that will develop into hardwood branches. The fan leaves will be large-sized and depending on which autoflowering cultivar you are growing, the growth structure will be bushy or one main central cola.

•  Grow Tip: Now is a good time to perform plant training techniques such as tying down, super-cropping, pruning, and in some cases topping and fimming.

Week 4

Once autoflowering plants are 28 days old, they will have grown to a height between 30-45cm in some cases. The growth structure will be well established with internodal spacing stretching out more as the weeks go by. It is during this time when the plants will go through a hormonal change inducing flowering.

It is best now to reduce the amount of Nitrogen you are giving the plants, as their primary focus will be Phosphorus and Potassium. It is the P and K that encourage the plants to grow pre-flowers and strong stems and side branches in preparation for a heavy harvest. Sativa dominant hybrids should be tied down here if the height is an issue.

•  Grow Tip: It is a great idea to add support such as bamboo stakes or a net trellis around the plants. Over the next 5-6 weeks they will focus on producing as much weight as possible.

Week 5

Now you are halfway through your growth cycle and will notice the growth structure and appearance of the plant will be growing tall, bushy, and with high resistance to strong winds.

Pre-flowers will be growing in abundance with resin production forming around the pistils, calyxes, and surrounding leaves. Depending on the cultivar you are growing, your plants will be as tall as 60-80cm, with new, fresh foliage being grown at every internodal site.

How Long Do Autoflowers Take From Seed To Harvest?: Pre flower Cannabis plant

Pre-flowers can be found between internodes and as the plant develops over weeks 4 and onwards.

•  Grow Tip: On the basis, you have trained your plants or used a screen, plant height can be easily controlled.

Week 6

By day 42, the plants will begin to fill out and take on a stacked and chunky appearance. The internodal spacing will become filled with flower sites, and the height of the plants will begin to slow down, as all energy is spent on flower production. The resin will begin to form very quickly covering the buds, with the aroma and terpenes making themselves well known. Plant height will range between 70-125cm

•  Grow Tip: Now the plants will depend on frequent amounts of nutrient solution, and using supplementary boosters and enzymes is an option to increase flower and resin production further.

Week 7

Once your autoflowering plants approach day 49, the structure will be very dense and compact, with buds swelling at every internode. The aroma will also become much more enhanced and when you squeeze a bud, your fingers will be stuck together with a layer of sticky resin. The total height of your plants now is 70-150cm depending on cultivar and climate.

•  Grow Tip: Some cultivars are more nutrient hungry than others, so do not overfeed your plants just because you are close to the harvest. Check how the plants look and respond between waterings.

Week 8

The buds will begin to fatten up and show signs of swelling up, with a prolific resin production. During weeks 8 is when the plants will be fed their last nutrient solution, as they will now be responsible for using up their reserve nutrients that have been stored over the duration of the plant’s life cycle. The plant's appearance will look chunky, heavy, and full of weight with tightly packed sugar leaves surrounding the buds.

•  Grow Tip: The white hairs on the plant will begin to fade to brown showing she is close to maturity. Do not judge the harvest date on the color of hairs, and use methods such as trichome development, bud density, and terpenes as a guide.

Week 9

As the plants get closer to the harvest date of 10 weeks, it is wise to encourage the plants to use up their nutrient reserve. The final two weeks are known as the flushing period, meaning that the plants will use up their reserve amounts of N-P-K and trace elements. It is normal to see deficiencies begin to form as this is a good sign the excess nutrients are being used up. The calyx of the bud will now bulge and swell with a round and pointy appearance. Trichome development will be at the peak maximum and now is a good time to start checking the maturity of your trichomes.

•  Grow Tip: There is no need to add more water than normal, or water more frequently, simply stick to the routine you have been using.

Week 10

Once you have hit the 10-week mark, your autoflowering plants will be fully mature and ready to harvest. The buds will be as thick as golf balls and should have filled every branch and internodal spacing. The terpenes will be the most aromatic, they can be, with the buds encrusted with trichomes, including the surrounding leaves. At this point, you are ready to get your trimming scissors out and begin harvesting the plants.

•  Grow Tip: By this point, the plants will display lots of different colors from deficiencies to end of seasonal colors, such as purples, pinks, and magentas.

2. The Advantages of Growing Autos

If you are new to growing autoflowering Cannabis, then you may not be aware of all of the advantages associated. In comparison to photoperiod strains that require 18/6, and 12/12, autoflowering cultivars are the opposite and will flower with any light cycle making them extremely versatile to all climates.

How Long Do Autoflowers Take From Seed To Harvest?: Autoflowers advantages

Benefits of choosing to grow autoflowering strains

Here at Fast Buds we pride ourselves on producing the fastest flowering autos on the market. Our strains will range between 9-10 weeks, which is extremely quick making them perfect for commercial growers, including novice to expert.

3. In Conclusion

Thanks to the toughness and high resistance to powdery mildew, mold, hot and cold climates, autoflowering Cannabis plants are the best way to grow top-shelf flowers from beginner growers to expert commercial farmers. 

Wedding Cheesecake Auto
Wedding Cheesecake Auto
Sativa 65%/Indica 35%
Wedding Cheesecake
9 – 10 weeks
450 – 600 gr/m2
90 – 130 cm
Up to 24%
< 1%
Buy seeds from 13,00 €
1 fem
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2 fem
24,00 €
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25 fem
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50 fem
365,00 €
100 fem
590,00 €
500 fem
1 950,00 €
1000 fem
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3 fem
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So, how long to grow weed from seed to harvest? With super fast flowering cultivars such as our Lemon Pie Auto, the harvest is possible every 8 weeks. If you are growing perpetually outdoors all year long, it is possible to harvest top-quality medicine, between 8-10 weeks depending on which cultivar is being grown.

21 April 2020