Outdoor marijuana grow calendar

Growing outdoors is the way to go for many growers. You don’t have to be concerned with expensive lighting and it’s natural.

However, you do have to take into account your place on the planet and how this affects your grow season. Because of this fact, I created this grow calendar for the United States and divided it into a northern- and southern states section.

Seeing that the marijuana plant has different needs throughout its lifespan, this Outdoor Grow Calendar covers the entire growing period. 

It also considers average day lengths and temperatures per region and provides info on when the flowering period starts outdoors.

What is a weed calendar?

A marijuana grow calendar provides a schedule that shows you what to expect, and what to do when growing marijuana outdoors. This weed calendar provides a schedule for the entire U.S.

Jump to the relevant month below if you live up north, or head to the southern grow calendar if you live in one of the southern states.

Generally, the outdoor growing season does not officially begin until mid-May. However, there’s plenty to do before that time comes. In fact, taking the time to prepare now, will make this season’s harvest even more bountiful.

Here’s the deal:

You can start preparing to grow in February, and if you factor in purchasing your seeds, marijuana growing can be a year-long thing.

Don’t forget to take some time to read up on best practices before you begin! Grab my free Grow Bible for more on growing outdoors.

Grow Bible

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  • Grow with my Quick Start Guide
  • Discover secrets to Big Yields
  • Avoid common grow mistakes


    How long is the marijuana growing season?

    A great way to get you started with your preparation is understanding how long the marijuana growing season is, as it will help you map out your weed calendar.

    An average cannabis plant takes around 3-4 months to grow from seed to harvest.

    However, many factors, such as the strain and size of your plant, affect the rate at which it grows. This is why the full range for outdoor growing is around 2-6 months.

    How long does pre-flowering last outdoors?

    Pre-flowering can take around 1 to 3 weeks, but that time can vary depending on the climate of your location and the strain you’re growing.

    It’s important to know when and how long pre-flowering lasts outdoors because this is the ideal time to check for and remove any male cannabis plants that have been growing alongside your females.

    It is tricky to know when pre-flowering will occur with outdoor plants since you can’t control the amount of light they receive.

    When does flowering start outdoors in northern states?

    Unlike auto-flowers, standard (photoperiod) cannabis strains do not flower based on age.

    They need to meet certain light conditions, which is why you may wonder, ‘when does flowering start outdoors..’

    Photoperiod strains will only flower once the daylight hours begin decreasing, which starts after the summer solstice.

    What does that mean when your question is ‘when does flowering start outdoor in Michigan?’ It means you should pay attention to the calendar as much as your plants. 

    In the Northern States like New York, Michigan, and Massachusetts, cannabis will generally begin flowering around July, but you may start seeing buds being developed as early as June.

    Other places like Southeastern Canada also share the same time as New York and the other states.

    However, in Oregon, Alaska, and Western Canada (BC), it may take a while for cannabis to flower due to the longer periods of daylight.

    When does flowering start outdoors in southern states?

    Outside of requiring certain light conditions to flower, most photoperiod cannabis strains also need a certain amount of darkness; otherwise, they might not even start flowering.

    This is where the 12/12 light cycle comes in, which represents 12 hours of daylight and 12 hours of darkness. Indoor growers know this cycle best as it is what they switch to in order to force their cannabis plants to flower.

    For outdoor growers, this cycle will start once the summer solstice has ended and the days start getting shorter.

    In the southern states like Florida and Virginia, which are closer to the equator, the day/night cycle is more balanced.

    Cannabis cultivated in those states typically begins to flower around August, when there are less than 13 hours of daylight.

    However, cannabis plants grown in Southern California will take longer to flower because it gets the most sunlight at that time. In general, the southern states flower a lot sooner than most Northern States. 

    How long is the flowering stage outdoors?

    If you are wondering how long the flowering stage is outdoors, the answer can vary. 

    This period can generally last for about 8 to 10 weeks; however, you can speed things up a bit with fast flowering strains.

    This can be very useful with a NY outdoor grow because you want to harvest before the snow arrives. 

    If you want to hasten the flowering stage of a non-fast flowering strain, you can place a tarp over your plants, creating darkness that forces them to flower.

    You should do everything you can to keep your plants from getting damaged by the cold as the winter solstice creeps in.

    Grow calendar – Northern States

    A Few Notes:

    • This section refers to the top half of the United States, including Alaska.
    • Averages are based on Seattle, Chicago, and New York
    • If you are growing on the northern West Coast, your springtime temperatures will be the warmer average, and your summer averages will be cooler than average
    • The most amount of sun is found in Alaska, with the Northwest coming in second

    February

    Average day length: 9.5 to 11.5 hours
    Average temperature: 22 to 51 degrees

    Alaska:
    Average day length: 8.5 to 10.5 hours
    Average temperature: -8 to 12 degrees

    buy your seeds

    It’s cold outside but now is the time to prepare for the upcoming season. Here’s a little shopping list to get you started:

    • Pots
    • Soil (and possibly other mediums)
    • Watering cans, jerrycans, sprays, and anything you need for prepping and feeding your plants.
    • Plant nutrients
    • And of course; seeds

    Many Northern growers choose Indica dominant plants because of the short growing season. Read the article “Best marijuana seeds for my climate” if you’re not sure what seeds grow best in your area

    In places like New York and Boston, it may seem like the frosty, cold temperatures will never end. However, if you start your plants indoors, you can extend your growing period so that you can grow any strain.  You can sprout your seeds indoors in a controlled environment with artificial light at the end of February.

    What’s more, if you want to make clones, you should germinate your seeds at this time. Keep your mother plants inside until it’s warm enough.

    Create a cozy indoor growing space with a CFL grow, 18 hours of sunlight and of course, some fresh air. Keep your grow area between 68 and 77 degrees. Check out “how to germinate marijuana seeds” for more on creating a cozy environment for germination.

    At this point, you can also begin prepping your soil if you aren’t in Alaska or the Midwest. After the last frost, loosen up your soil by adding worms and compost.

    Here’s an example of a strain that grows well in slightly colder climates:

    super skunk cannabis seeds

    Buy Super Skunk seeds

    • 80% Indica 20% Sativa
    • THC levels up to 20%
    • Easy-growing strain with high yields

    March

    Average day length: 9.5 to 13 hours
    Average temperature: 31 to 54 degrees

    Alaska:
    Average day length: 10.5 to 13 hours
    Average temperature: 0 to 24 degrees

    Start sprouting your plants

    It’s starting to warm up on the coasts, and the days are getting very long around Seattle and Portland. Growing time is getting close. If you haven’t already ordered your seeds, do it now!

    You should also have your mother plant ready by the end of this month if you plan to clone.

    If you are ready to go, you can start sprouting your plants in a windowsill at the end of the month. Make sure they get some good sunlight and keep a good watch on the day length.

    By this time, areas near Seattle are receiving more than 12 hours of sunlight, while Alaska has 13.

    If you plan to grow two rounds of autoflowers this season you should definitely start sprouting those beans.

    If you’re doing just a single round of autos you can best wait another month with germinating.

    Blueberry is a delicious strain due to its fruity taste. Autoflowers generally do well in cooler climates due to the ruderalis traits. Plus, when you’re early you can do two runs in a season! Learn more

    Blueberry Autoflower Seeds

    Buy Blueberry Autoflower seeds

    • 80% Indica 20% Sativa
    • THC levels up to 14%
    • Great for in- and outdoors

    However, most of the country will not have as much sunlight.  In this situation, you can provide it for them. If your plants aren’t getting enough sunlight, set a lamp over your plant a few extra hours each day. That way, you won’t have to worry about premature flowering.

    April

    Average day length: 12.5 to 14.5 hours
    Average temperature: 35 to 62 degrees

    Alaska:
    Average day length: 13.5 to 15.5 hours
    Average temperature: 24 to 45 degrees

    start putting plants outside

    Congratulations, it’s April! That means flowers, followed by May showers. The middle of this month marks the beginning of long days, with everyone having at least 14-hour days by the end of the month. Once the days are that long, you will not need any more artificial lighting.

    Your windowsill plants will not need any more help with light once the days reach 14 hours, and your seeds will find it easy to sprout.

    By the end of the month, it’s safe to take your plants outside – especially if you are on the West coast.

    Simply put them in a container and put them outside, bringing them indoors at night.

    Midwest growers may want to make sure the risk of frost has passed first.

    Alaskan growers will need to wait another month or place the plants in containers and bring them inside during cold nights.

    If you created a mother plant, it’s time to make clones. Need help with that? The article “How to make clones” explains the process.

    May

    Average day length: 14 to 15.5 hours
    Average temperature: 52 to 72 degrees

    Alaska:
    Average day length: 15.5 to 17.5 hours
    Average temperature: 40 to 61 degrees

    put your cannabis plants outside

    It’s finally Spring – even in Alaska. If you live on the Alaskan coast, it’s probably okay to start placing your plants outside. Stay vigilant for frost, of course.

    The Alaskan interior should wait until the middle of the month – just to be safe.

    Also read The Best Places To Grow Marijuana Outdoors

    If you have autoflowering seeds, you’ll begin sprouting them the second half of this month. They need three months of summer to grow. Given that in some parts of the Midwest and Alaska, that’s all the time you will have before the freezing temperatures return, so work quickly. Expect your harvest to be ready mid-August.

    June

    Average day length: 15 to 16 hours
    Average temperature: 54 to 81 degrees

    Alaska:
    Average day length: 18 hours
    Average temperature: 52 to 71 degrees

    Plants are getting flowers

    June is when your plants will experience the most growth – especially between June 18th and June 24th. At this time, you’ll see your autoflowering plants grow rapidly as they begin to develop flowers. Your non-autoflowering plant will also speed up, thanks to the warming temperatures.

    Here’s my full guide on what to keep in mind during the vegetative stage.

    July

    Average day length: 14 to 16 hours
    Average temperature: 58 to 85 degrees

    Alaska:
    Average day length: 16.5 to 18 hours
    Average temperature: 55 to 73 degrees

    Male vs Female buds

    During this hot month, your autoflowing plants will develop large flower clusters, while some non-autoflowering plants will grow their first pistils.

    If you decided to use feminized seeds (non-feminized), now is when you’ll need to start paying attention and check for male plants. Keep an eye on the side branches and quickly remove them. You’ll recognize the males because they will develop flowerheads at the root of the side branch. These flowerheads will look like two small balls resting on a short, thin stem.

    Female plants, however, will have drop-shaped calyxes with two white pistils protruding from them.

    See the above image for comparison.

    August

    Average day length: 13 to 15 hours
    Average temperature: 58 to 84 degrees

    Alaska:
    Average day length: 14 to 16.5 hours
    Average temperature: 49 to 66 degrees

    dry your autoflowers now

    Remember those autoflowers that sprouted back in late May? It’s now time to harvest them. Cut the flower heads and hang them upside down in a dark place to dry. Dry them at room temperature – don’t try to speed up the process by making it too hot. It should take about 10 days.

    You’re done when the branchlet cracks when you bend it.

    Here’s my full guide on drying your plants.

    Near the end of the month, most areas will have less than 14 hours of sunlight. Alaska is the exception. Once this happens, non-autoflowering plants will begin their flowering phase.

    Catch up on how to manage the flowering phase.

    September

    Average day length: 11.5 to 13.5 hours
    Average temperature: 54 to 76 degrees

    Alaska:
    Average day length: 11.5 to 14 hours 
    Average temperature: 38 to 55 degrees

    take marijuana plants inside

    If you are growing non-autoflowering plants, (photoperiod plants) they will start developing more pistils and flowerheads at the beginning of this month. You’ll want to make sure they stay dry during this time – perhaps, build them a dry shelter, or take them indoors on moist days.

    Be sure to read up on when and how to harvest your plants with our free mini harvesting guide

    The wind can also be a problem during this month as the seasons start to change. In any case, prevent your plants from falling over by adding a net or using bamboo sticks.

    Fall officially begins the end of this month, but it will be a slow transition on the West Coast and in Alaska as the sun tends to linger around a bit longer.

    October

    Average day length: 10 to 13 hours
    Average temperature: 46 to 64 degrees

    Alaska:
    Average day length: 11.5 to 14 hours 
    Average temperature: 20 to 33 degrees

    Bud rot on a plant
    Bud rot

    Autumn is officially here, and many outdoor-grown plants have bloomed. Unfortunately, this is a high-risk time for most northern growers. Especially in areas where it’s cold (Midwest and Alaska) or wet (Pacific Coast), you need to keep an eye out for bud rot.

    If you notice any signs of bud rot (see above image), it’s time to harvest. An early harvest is better than none at all. Read more about bud rot in the article “How to prevent Bud Rot”.

    Also, keep your eye on the temperatures. Jorge said it best:

    “Many plants can take a short mild freeze (30-32°F). But of the temperature stays below freezing for more than a few hours, it could kill plants.”

    Jorge Cervantes

    Enjoy your harvest and, if you’re up to it, why not start an indoor grow over the winter!

    Grow calendar – Southern States

    Just like growers in the northern states, by all means, get a head start. As I have said, you can start as early as February. Sure, the true outdoor growing season doesn’t begin until mid-May, but why wait? After all, there is a popular saying: “the early bird gets more bud,” or at least that’s how I remember it.

    Click here to jump to the grow calendar for the northern states.

    In the southern states, the last frost signals “go time”. After that, use this calendar to help plan the year’s grow season.

    A Few Notes:

    • This section refers to the bottom half of the United States, plus Hawaii.
    • Averages are based on Los Angeles, Houston, and Miami
    • Southern West Coast growers can expect the most sun and the coolest average temperatures year-round.
    • Central areas will have the hottest summers, while the Southeast will experience the hottest spring and fall.
    • The shortest summer days are in Hawaii.

    February

    Average day length: 10.5 to 11.5 hours
    Average temperature: 49 to 80 degrees

    Hawaii:
    Average day length: 11.5 hours
    Average temperature: 67 to 81 degrees

    Start sprouting your seeds

    Time to buy seeds! For most of the southern United States, the threat of frost has passed and it’s just about time to start growing. Because of the extended growing season in some areas of the south, it’s safe to choose Sativa dominant plants. If you opt for an Indica, the first thing to remember is how hot your summers generally become.

    Read the article “Best marijuana seeds for my climate” if you’re not sure what seeds grow best in your area.

    Blue Dream is one of our most popular Sativa dominant strains due to its energizing yet mellow buzz.

    Blue Dream Seeds

    Buy Blue Dream seeds

    • 20% Indica 80% Sativa hybrid
    • High THC levels up to 21%
    • Consistent heavy yields

    You can also begin sprouting your own seeds indoors, but be sure they stay warm enough until they can go outdoors. Seedlings prefer a temperature between 68 and 77 degrees.  Of course, some areas such as Hawaii and southern Florida, boast February temperatures like these,  however, your plants will also need 18 hours of sunlight.  Due to this, you will need to invest in some CFL grow lights until the days get a bit longer to sprout seeds early.

    For more information on germinating your seed indoors, read “how to germinate marijuana seeds.”

    February is also a great time to prep your soil. Loosen it up a bit by adding compost and worms.

    March

    Average day length: 11.5 to 12.5 hours
    Average temperature: 50 to 81 degrees

    Hawaii:
    Average day length: 11.5 to 12.5 hours
    Average temperature: 68 to 82 degrees

    sprouting seeds in the window

    The warmest areas of the United States are starting to feel like summer, and the interior is no longer at risk of frost. Assuming you already have your seeds, you can begin sprouting plants in the window sill . Your plants need at least 12 hours of sunlight, so if the days are not quite long enough yet, add a lamp an extra hour a day to make sure they receive enough.

    If your plants do not get enough sunlight, they may start flowering early – and you do not want that.

    My free Grow Bible has all the details you need for your outdoor grow.

    Grow Bible

    • Grow with my Quick Start Guide
    • Discover secrets to Big Yields
    • Avoid common grow mistakes


      If you decided to use a mother plant, spend some time tending it. It needs to be ready by the end of the month if you plan on using your clones outdoors.

      April

      Average day length: 12.5 to 13.5 hours
      Average temperature: 55 to 84 degrees

      Hawaii:
      Average day length: 12.5 to 13 hours
      Average temperature: 70 to 83 degrees

      sprouting cannabis outside sun

      April raises the temperature just a bit and lengthens days significantly (except in Hawaii). You’ll notice the longer days around the middle of the month, with most southern areas reaching 13 hour days by the end of April. At this point, you won’t need those lamps in your windowsill anymore. Make sure your plants receive as close to 13 hours of sunlight as possible, and your seeds should easily sprout.

      In fact, if you live in the Southeast, it’s probably safe to take your plants off the windowsill and into the fresh air. The Southeast tend to have the warmest spring temperatures in the southern half of the United States. As a rule of thumb, if it’s 70 degrees, you’re probably okay to let them sit outside during the day. Remember to bring them indoors at night!

      If you’re planning on growing autoflowers this season, now is the time to get your seeds in the mail.

      This is a classic and longtime favorite of mine. Be sure to try these if you’re in the market for autoflowers this season.

      White Widow Autoflower

      Buy White Widow seeds

      • 60% Indica 40% Sativa
      • THC levels up to 19%
      • Very easy to grow plants

      If you created a mother plant in late February, now is the time to start making your clones. Read the article “How to make clones” for more information

      May

      Average day length: 13 to 14.5 hours
      Average temperature: 60 to 87 degrees

      Hawaii:
      Average day length: 13 to 13.5 hours
      Average temperature: 71 to 85 degrees

      Spring has arrived – although, in some places, it already feels like summer. Go ahead and place your plants outside permanently.

      Plant your autoflowering seeds by the middle of the month. By that time, they’ll have plenty of sunlight to grow, and the temperature is just right. You’ll be ready to harvest the beginning of August. As a note to any Hawaii growers, do not choose strains that require higher than average amounts of sunlight for outdoor growing, as Hawaiian summer days are the shortest in the country.

      June

      Average day length: 14.5 hours
      Average temperature: 60 to 91 degrees

      Hawaii:
      Average day length: 13.5 hours
      Average temperature: 74 to 87 degrees

      growing outdoor june

      June is when outdoor marijuana plants grow the most – specifically between June 18th and June 24th. Autoflowers begin to develop flowers, and non-autoflowers grow faster.

      June is also when Hawaii starts to experience the shortest days in the country, as compared to California, where outdoor plants receive up to 90 extra minutes of sunlight.

      July

      Average day length: 13.5 to 14.5 hours
      Average temperature: 65 to 93 degrees

      Hawaii:
      Average day length: 13 to 13.5 hours
      Average temperature: 75 to 88 degrees

      grow calendar first pistils

      The hottest month of the year produces large flower clusters on autoflowers while your non-autoflowers may show their first pistils.

      If you used regular (non-feminized) seeds,  look for pesky male plants. Watch those side branches for flowerheads at the bottom of the side branches.  They will look like two small balls resting on a short, thin stem. If you see them, quickly remove them. Females, on the other hand, will have drop-shaped calyxes with two white pistils protruding from them.

      August

      Average day length: 13 to 14 hours
      Average temperature: 65 to 95 degrees

      Hawaii:
      Average day length: 12.5 to 13 hours
      Average temperature: 75 to 89 degrees

      drying cannabis strains

      You can harvest your May autoflowers! Cut off the flower heads and hang them upside down in a dark place to dry. Don’t try to rush the process by messing with the temperature- dry at room temperature.

      Drying should only take about 10 days. Test for readiness by bending a small branch. If it cracks, it is ready! Read more on this in the article:  “How to harvest marijuana plants.

      You may also be able to harvest your non- autoflowers since the days have dropped below 14 hours and you must do so before 13. If you are in Hawaii or the Southeast, due to their shortened outdoor growing season, you should choose autoflower strains with short growing cycles.

      Once the days drop below 14 hours, non-autoflowering plants start their last flowering phase and begin to die. If you have limited amounts of daylight, bring them indoors and use lamps to extend the growing season a little bit longer.

      For non-autoflowering (photoperiod) plants that are not ready to harvest, you’ll see more pistils and flowerheads. Protect them from the wind and keep them dry by building a shelter or bringing potted plants inside. You can also stabilize them with bamboo sticks.

      September

      Average Day length: 12 to 13 hours
      Average temperature: 64 to 89 degrees

      Hawaii:
      Average day length: 12 to 12.5 hours
      Average temperature: 75 to 89 degrees

      plant ready to harvest

      Fall comes at the end of this month, but some parts of America may not notice, at least temperature-wise. However, the shorter days near the end of the month are a clear indicator that the growing season is nearly over.

      Many plants will be ready to harvest during this month if you haven’t already.  Read my article “How to harvest marijuana plants” for more info.

      October

      Average day length: 11 to 12 hours
      Average temperature: 60 to 86 degrees

      Hawaii:
      Average day length: 11.5 to 12 hours
      Average Temperature: 74 to 87 degrees

      bud rot weed
      Bud rot

      Autumn is here and the outdoor growing season is officially over. While plants in most of the southern United States should have already bloomed, there may be some that finish up this month. If your plants are still growing at this time, be especially careful of cold, wet temperatures. This can cause bud rot, which can ruin your harvest. The heartland of America is most at risk for this.

      If you notice any signs of bud rot, harvest immediately – some is better than none. Read more in the article “How to prevent Bud Rot

      Enjoy your harvest and if you’re considering an indoor grow over the cold season, here’s something to help your plants stay warm.

      There are many climate regions in the United States, each impacting your plant’s growing season. Be that as it may, marijuana loves mild temperatures and plenty of sunlight, which can be found in many parts of the country.  The important thing to remember is that marijuana loves sunlight. As a result, growing outdoors means you need to time your growing for when it can receive the most of it.

      When to harvest outdoor weed – 3 quick tips to know it’s time

      Timing is everything, especially when growing cannabis outdoors in colder climates.

      If for example, you wanted to know when to harvest outdoor weed in Colorado, you must learn to recognize some signs. 

      There are three reliable methods for knowing when to harvest marijuana plants.

      The first method involves looking at the leaves, trichomes, and pistils of your cannabis plants. Once the leaves have begun to turn yellow and fall off, it’s a sign that your plant is diverting a lot of its energy into growing out its buds.

      To know when your plants are ready to be cut down and dried, though, you’ll need to closely look at the trichomes and pistils with a handheld magnifier.

      Look for a milky white color in your trichomes. It’s okay if there are a few amber-colored ones mixed in. For the pistils, you’ll know the buds are ripe if 90% of the white hairs have become brown.

      The two other methods involve making good use of your weed calendar.

      Some growers say the September equinox is the time to cut down and harvest your plants; however, it’s not a ‘hard-set’ rule.  It’s mainly used as a date to stop watering your plants

      Lastly, there’s the method of harvesting based on flowering time.

      Each strain has its own flowering time.

      Growers have used that as a basis for knowing when to harvest their plants. If it’s an indica, harvest after 8 weeks of flowering. If it’s a sativa, 10 weeks. For auto flowers, it usually takes 10 weeks from seedling to bud.

      Do you grow in the United States? Did we leave something out?

      Let us know in the comments, and we’ll update this calendar. Together we can share knowledge to grow the best marijuana in the USA.

      FAQs about outdoor grow calendar

      Why are my outdoor plants flowering early?

      Your plants might not be getting enough sunlight. Setting a lamp over them daily for a few extra hours should help. They need at least 12 hours of sunlight every day.

      How often do you water during the flowering stage?

      You should water your plant every 2 to 3 days during the flowering stage. However, you need to make sure you give it enough water. Overwatering or underwatering the plant will affect its growth. Read When And How To Water Cannabis Plants for more information. 


      Here’s to a great harvest!

      Robert

      ilgm outdoor grow calendar
      Avatar for Robert Bergman

      Robert Bergman

      Robert Bergman is an Amsterdam-based marijuana grow expert who has years of experience from small grows to massive operations. His passion for growing led him to develop his own Gold Leaf strain. Now, Robert is dedicated to sharing his knowledge with the world.... [Read full bio]

      GROW BIBLE

      marijuana grow bible
      • Grow With My Quick Start Guide
      • Discover Secrets To Big Yields
      • Avoid Common Grow Mistakes