The Definitive Cannabis Grow Calendar: Northern Parts Of The USA

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October 01, 2020

Indoors, you can grow marijuana regardless of where you are, any time of the year. That is not the case for outdoors as the amount of light differs from one region to another.

The length of days in the Northern and Southern United States are not the same. Hence, you would need to know the ideal grow calendar in a specific geographical location to cultivate cannabis successfully.

Before you start check out Homegrown Cannabis Co.’s great selection of outdoor cannabis seeds and pick from any of the excellent marijuana strains perfect for growing outdoors.

An excellent way to understand a suitable growing schedule in the northern parts of the USA is to use a sample calendar.

Marijuana Outdoor Grow Calendar for Northern USA

This outdoor growing calendar covers the entire lifespan of marijuana plants. The climatic conditions are predicted based on the average length of days and temperatures in the northern region. It also includes Alaska.

In general, the growing season begins in mid-May. Before that, you should spend the time preparing, starting as early as February.

Here are a few things to consider:

  • The day length and temperatures are averages based on the states of Seattle, Chicago, and New York.
  • For the Northern West Coast, use the warmer average temps for springtime and the cooler average temps for summertime.
  • Alaska has the most amount of sunlight in the Northern USA, with the Northwest coming in second.


Northern USA Alaska
Average Day Length (hours) 9.5 to 11.5 8.5 to 10.5
Average Temperature (°F) 22 to 51 -8 to 12

Now is not the time to grow marijuana. However, this is the best time to begin preparing. The things you need include the following:

Pots. Consider using soda cups for seedlings, small-to-medium pots for the vegetating plants, and the final containers.

Potting Mix. You would, of course, need it for seedlings.

Nutrients. A high-quality potting mix would also have enough nutrients for the seedlings. Once they enter the vegetative stage, you would need to provide them with nitrogen-rich nutrients. You might also want to buy fertilizers for the flowering stage.

Seeds. It is not too early to think of buying seeds. Now would be a good time to decide which strain to grow and obtain the seeds from a reputable seed bank.

Others. Think through the whole cultivation process – the equipment, tools, and consumables – from germinating the seeds to harvesting, drying, curing, and storing the buds. Anything that you need, it is better to have them on hand, once required.

Once you are ready, consider germinating the seeds and keeping the seedlings indoors using CFL. At this point, they will not likely survive the cold in the outdoors. Inside the house, make them feel comfortable and warm enough under an 18/6 light cycle. The ideal temperature would be around 68 to 77°F.

Unless you are in the Midwest or Alaska, you can also start preparing the soil by loosening them up, adding worms, and compost.


Northern USA Alaska
Average Day Length (hours) 9.5 to 13 10.5 to 13
Average Temperature (°F) 31 to 54 0 to 24

By this time of the year, the days are getting longer in Seattle and Portland. It is also getting warmer. No more dilly-dallying, you need to have the seeds soon or risk missing the window for growing. Not sure where to buy seeds? Homegrown Cannabis Co. has more than 400 in-house cultivars, and can quickly have them shipped.

If you do have the seeds, germinate the planned number of plants if feminized, or twice as much if regular. And if you are not sure what to do at this point, here’s master grower Kyle Kushman explaining his proven method of germinating seeds.

For auto-flowering seeds, when you sprout the seeds depend on your preference. Do it now if you want to do two rounds in one season, or next month to grow only once.

In places like Seattle, you would be getting at least 12 hours of sunlight while Alaska would be getting 13 hours. Let the seedlings bask under the sun, by the windows.


Northern USA Alaska
Average Day Length (hours) 12.5 to 14.5 13.5 to 15.5
Average Temperature (°F) 35 to 62 24 to 45

April marks the time when the days are, indeed, longer. Most especially towards the end of the month, you would be getting 14-hour days. That means your little plants no longer have to rely on CFL. Even on a windowsill, they will receive adequate lighting. If what you have, at this point, are seeds, then they will soon sprout.

If you live on the West Coast, you should be able to bring seedlings outdoors during the daytime. In the Midwest, make sure that there is no risk of frost before bringing them outside. Do bring the young plants indoors in the evening to keep them protected from excessive cold. If you do so, ensure darkness during the dark cycle so as not to confuse them.

Note: You will have to wait one more month if you live in Alaska.


Northern USA Alaska
Average Day Length (hours) 14 to 15.5 15.5 to 17.5
Average Temperature (°F) 52 to 72 40 to 61

As the days get warmer in Alaska, you should be able to bring the young plants outdoors. Although it is springtime, you still want to make sure that they do not go into shock in case of frost. Around the middle of the month, it should be all good.

Autoflowering weed seeds need around three months from the time of sprouting to reach full maturity. That means you will have to germinate auto seeds by mid-May – that allows them enough time to grow before the freezing temperatures are back. You should expect to harvest the autos by mid-August.

As for photoperiod strains, they should now be growing in mass, developing more branches, stems, and leaves. Nothing beats the sun with regards to providing the best light spectrums for optimal growth.


Northern USA Alaska
Average Day Length (hours) 15 to 16 18
Average Temperature (°F) 54 to 81 52 to 71

June is when you see the young plants rush into adulthood, especially between June 18 to 24. It is when they will receive the most sunshine, allowing them to go on hyperdrive. For autos, expect an explosive growth as they enter the flowering stage.


Northern USA Alaska
Average Day Length (hours) 14 to 16 hours 16.5 to 18
Average Temperature (°F) 58 to 85 55 to 73

July marks the time when your plants start growing their first pistils. It is when you become extra vigilant in identifying gender. Over the next few days, you would need to watch out for any males and remove them as quickly and as gently as possible. What to do with them is entirely up to you. If you need male plants, then you will want to relocate them far away from the females.

As for autoflowering plants, your journey is soon coming to an end. You should be seeing them produce and develop large flowers.


Northern USA Alaska
Average Day Length (hours) 13 to 15 hours 14 to 16.5
Average Temperature (°F) 58 to 84 49 to 66

If you are growing autoflowering plants, rejoice. Those seeds that you germinated back in May are now fully mature plants. You will want to observe the colors of trichomes and pistils to determine the best time to harvest the buds.

As for the photoperiod plants, much of the Northern USA would now have less than 14 hours of daytime with the exemption of Alaska. Soon, they will enter the flowering stage.


Northern USA Alaska
Average Day Length (hours) 11.5 to 13.5 hours 11.5 to 14
Average Temperature (°F) 54 to 76 38 to 55

During the first week, expect your plants to continue developing more pistils and flowerheads. They should not be exposed to high humidity. If needed, you may need to bring them indoors on days when the moisture is excessively high. Furthermore, the wind might be too strong, so you have to be mindful of that. You can use a net to protect them, or plant bamboo stakes for support.

Fall season starts as the month comes to an end. The transition will be a bit slower on the West Coast and Alaska, though, as these areas still have longer daytime compared to the rest of the Northern USA.


Northern USA Alaska
Average Day Length (hours) 10 to 13 hours 11.5 to 14
Average Temperature (°F) 46 to 64 20 to 33

Autumn is beautiful but not as much for the plants. As the temperature falls, your plants are now more susceptible to the cold. Although the plants may survive a short spell of 30-32°F, they cannot withstand prolonged exposure to low temps. It is precisely why Indica strains are preferred as they are more tolerant than Sativa.

If you live in the Midwest and Alaska, be mindful of bud rot. High moisture may cause the proliferation of bacterias and fungi. These disease-bearing organisms may attack the buds from the inside out. If that is a problem, then follow this guide on how to remedy and save the plants.

Recommended Strains

Considering the colder climate in the northern region, it makes sense that most people prefer Indica strains. For one, they have a quicker life cycle. More importantly, most of these strains have roots in the harsh, cold climate of the Hindu Kush region and are accustomed to colder temperatures.

Grandaddy Purple Regular

  • Genotype: Indica hybrid
  • THC: 17-24%
  • Flowering Time: 8-11 weeks; Mid-October
  • Yields: Heavy
  • Recreational: Uplifting and euphoric
  • Medical: Pain and insomnia

Super Skunk Feminized

  • Genotype: Indica hybrid
  • THC: 19%
  • Flowering Time: 6-8 weeks; Late September
  • Yields: Heavy
  • Recreational: Expansive and numbing
  • Medical: Stress and tension

Blueberry Regular

  • Genotype: Indica hybrid
  • THC: 15-24%
  • Flowering Time: 8-9 weeks; Mid-October
  • Yields: Heavy
  • Recreational: Euphoric and relaxing
  • Medical: Tension and stress

Blueberry Autoflower

  • Genotype: Indica hybrid
  • THC: 15-24%
  • Flowering Time: 8-9 weeks from seed to harvest
  • Yields: Medium
  • Recreational: Stimulating and optimistic
  • Medical: Depression and stress

Should You Follow a Grow Calendar?

The growing schedule provided for Northern USA and Alaska is merely an illustration of what to expect. As you saw, there was no mention of the things you need to do – providing nutrients and training the plants. It does give you an idea of how the climate changes over the season. As such, you can plan your schedule and focus on providing your babies the best care.

Your main concern is the cold temperature. Preparation should begin as early as February and harvest before it gets too cold – that is your window. Marijuana is an annual plant, so you can only grow one round. But if you want to grow up to two rounds, then you should consider auto-flowering strains. Whichever you choose, you can grow successfully as long as you stick within your window.