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Marijuana Growing Calendar – Weed Seasons

Marijuana growing calendar

Mar 24, 2021
Outdoor Grow Calendars

Marijuana Growing Calendar


Weed seasons are the times of year that would be the best for growing cannabis. We present this marijuana growing calendar to you to help you along your grow journey.


There are a lot of factors that go into growing a healthy, high-yield cannabis plant. Growers have to choose what strain they want to grow, the growing medium they will use, where they will grow their plants, and what type of nutrients they will use. Perhaps one of the most crucial elements of how to grow marijuana successfully is following the appropriate marijuana growing calendar.


The Basics of Growing Marijuana


Cannabis plants have varying requirements for light, water, and nutrients depending on the growth phases of the plants, all of these factors are dependant on the different weed seasons throughout the year if you’re growing outdoors. Growers have to take into account the temperature of the growing area, the light exposure the plants have, and the lifespan of the strain they choose to grow.


Furthermore, if a grower chooses autoflower seeds, it can change the schedule entirely. For this reason, understanding the basics of what a plant needs and following the appropriate grow schedule are critical steps in getting the best yield possible.


Growing Phases

Whether a person is growing indoor or outdoor, there are some requirements that remain the same. Whether or not a plant is autoflowering, cannabis plants have distinct stages. These stages are germination, seedling, vegetative, and flowering stage. 


Most well-established strains have guidance as to how long growers can expect each stage to last naturally. Each stage of growth requires different tweaks to its environment and nutrient schedule to promote optimal growth. 


Autoflowering Marijuana


While autoflowering marijuana requires many of the same growing conditions as photoperiodic cannabis plants, there are some crucial differences. One of the most important differences being that the plant enters the flowering stage based on how many days it has been since the seed germinated rather than the number of light hours the plant receives. While traditional cannabis plants can take up to 9 months to reach harvest, these plants have much shorter growth stages, with a total lifespan of anywhere between 8 and 16 weeks. 


Growing Marijuana Indoors


Growing marijuana plants indoors gives the grower ultimate control over many factors that would otherwise be left to nature, so following a grow calendar isn’t as crucial. Growers can essentially force plants into the flowering stage by manually reducing the number of hours the grow lights are on. They can also control the temperature and humidity of the grow room, making it easy for them to grow year-round regardless of the climate in which they live. Naturally, weed seasons do not have any control over when to plant marijuana when growing indoors.


The versatility of indoor grows makes it much less crucial for growers to follow an indoor grow calendar based on the date or time of year. Instead, they can create the environment needed to produce the results they want, basing it on the type of plant they are growing. It is important for them to know the approximate length of each stage for the strain they are growing and to adjust the environment accordingly.


A Calendar for Growing Marijuana Outdoors


Growing marijuana outdoors is much more dependent on the climate where the plants are grown. Growers will need to consider the average day length throughout the year when the flowering stage starts outdoors and the region’s temperature fluctuations. Growers must ask how long is the flowering stage outdoors, as flowering time can be anywhere between 8 and 16 weeks, depending on the strain.


Many outdoor growers find themselves asking, “does growing weed smell?”. While it does have a distinct aroma, it is much less obvious when growing outdoors. Wind can carry the smell away, so it’s difficult to pinpoint, and local animals, such as skunks, can make it seem like a harmless odor. 


The grow calendar below will help growers in northern and southern regions of North America plan their cannabis garden. It will help guide growers on what to expect during the growing season. Starting from when to plant weed outdoors, our marijuana growing calendar will take you through every step of the grow cycle.


Northern Outdoor Grow Calendar


Northern areas of North America have much shorter growing seasons than the south. Technically, plants shouldn’t be outdoors until mid-May, but there are several things that can be done indoors before the season officially starts. Preparations made early on can help boost growth throughout the season and encourage a bountiful harvest. For best results, follow the grow calendar below. 




In the north, February is known to be a bitterly cold month. Temperatures can range between 22 and 51 degrees, with areas near Alaska reaching as cold as -8 degrees on average. While it is far too cold to consider planting anything outside, growers can start gathering the supplies they will need for the season. Some supplies include pots, growing medium, nutrients, watering cans, and weed seeds


Cannabis sprout in February


Growers that are planning to clone their cannabis plants should germinate seeds now, making sure to keep them under an artificial light that is kept on for 18 hours. The grow room should be kept between 68 and 77 degrees, and growers should prep their soil for transplanting seedlings into pots. 




By March, some areas in the north have up to 13 hours of daylight, though many will still linger under 12. Temperatures are higher but still not high enough for planting outdoors, especially in far north areas like Alaska. Growers should have chosen strains by now and have them ordered early in the month.


Growers in northern regions should try to grow strains with a shorter overall lifecycle and that are known to be cold tolerant. Growing these strains helps protect them against having to harvest early or losing plants due to a cold snap. By the end of March, growers in this region can start sprouting their seeds. Growers who choose autoflower strains can either start their seeds now to fit two harvests into the season or wait a bit longer to sprout their seeds.




In April, northern regions will start to see the first signs of spring, with temperatures up to 62 degrees on average, and the average length of a day is between 12 and 15 hours. However, overnight frosts and cold days are still common at the beginning of the month, so plants are not quite safe to be placed outdoors in most areas. By the end of April, plants can be taken outside in most areas. April is the month you can truly start growing outdoors.


Cannabis vegetative outdoors

With days over 14 hours, plants are no longer going to require artificial lighting. However, it is important to slowly introduce plants to direct sunlight, as doing so too quickly could shock them and cause leaf burn. Far north regions, such as Alaska, should wait another month before moving plants outdoors.


Growers who grew a mother plant can begin taking clones at this time. 




Once May arrives, spring is in full swing, even in far northern regions. The temperature is comfortably between 50 and 75 degrees and daylight hours are around 15 in most areas. In some places, it reaches as high as 17.5 hours. 


It is probably safe to move cannabis plants outdoors, though growers should watch the weather closely as there can sometimes be one or two more frosts early in the month. Autoflower seeds can be germinated around the middle of May. 




In June, summer weather starts to creep in. Temperatures reach the 80s in some places, and these are the longest days of the year, reaching between 16 and 18 hours of light. All plants can be safely put outdoors, though it will be time to monitor for other threats, such as bug infestations and plant diseases.


This is the month where plants will experience the highest growth rate, especially towards the end of the month. Autoflowering plants will see the first signs of flowering, but growers shouldn’t worry. Autoflowers can still put on a lot of bulk after the flowering stage starts. 


Growers must be sure they are following a nitrogen-rich nutrient schedule and giving their plants plenty of water. Growers who are not growing feminized seeds may be able to see signs of male plants during the last weeks of the month.




July is a hot month, with temperatures averaging well into the 80s during the day and some areas peaking into the 90s at times. Outdoor cannabis plants will still be getting 16-18 hours of daylight. 


During this time, autoflowering plants will start to develop flowers, while some strains of traditional cannabis will have white pistils. Male plants must be removed before female plants form pistils, or growers risk fertilizing their female plants. Male plants can be identified by the tiny ball-shaped flower heads they form at the start of a side branch. 


Where male plants have flower heads, female plants have pistils. Once the female plants start to show signs of flowering, growers should slowly transition them to a bloom-supporting nutrient schedule. 




In August, days are markedly shorter than they were in June, with between 13 and 15 hours of daylight in most places. Temperatures are still comfortable in the 80s during the day but may drop into the 50s at night. 


Growers who started autoflower seeds in May will likely need to harvest their plants by the end of this month. They can be harvested by cutting the flower heads and hanging them upside down in a dry, dark area, room-temperature area. Drying can take between 5-10 days, depending on the size of the flower. 


Once the region reaches less than 14 hours of light, all non-autoflowering plants will be in the flowering stage, though the overall cannabis flowering time varies by strain. It is important for growers to adjust their nutrient schedule accordingly. 




In September, days are noticeably cooler and shorter. Most regions will have 11 to 13 hours of light per day and experience temperatures between 50 and 75 degrees. Far north regions, such as Alaska, will have temperatures drop into the 30s. 


Non-autoflowering plants will start developing buds early in the month. It is important to keep buds as dry as possible to avoid mold growth. Growers should also protect plants against wind and support the branches as dense buds will weigh branches down, which could cause branches to snap. 


Fall officially starts at the end of the month. Now is a good time for growers to read up on how to tell if their plants are ready to harvest. Total cannabis flowering time varies by strain, so it is important to know what to expect. 




October’s days are between just 10 and 13 hours long, and temperatures range between 45 and 65 degrees in most areas. Frosts are likely to start towards the end of the month, so growers should keep an eye on the weather and be prepared to protect their plants. Far north areas will be colder, dipping into the 20s, so growers in this region should not keep plants outside. 


October is the marijuana harvest season. This means you have to figure out when to harvest outdoor marijuana, however, you still have to be careful of when you harvest so you don’t encounter any mistakes during the later stages of the marijuana growing season.


Growers should watch for bud rot at this time, especially if they live in an area that gets a lot of rain. Plants should be ready to harvest by the end of the month. 


Southern Outdoor Grow Calendar


There are many similarities between growing marijuana in northern and southern regions, but southern regions have the benefit of a longer growing season. This opens them up to strains that take longer to reach maturity, such as Blue Dream. However, it is critical that they keep an eye on how hot the summer temperatures are, as this can pose a problem for growing plants. For best results, follow the grow calendar below.  Find out when to plant cannabis outdoors in the southern regions of America and also how to maintain your plants and what to expect throughout the different weed seasons.




In February, temperatures in southern regions can range between 50 and 80 degrees, but days are only 10.5-11.5 hours long. It is not entirely uncommon to see a night of frost in warm regions farther north, so growers should be careful about doing anything outdoors at this point. Instead, they can focus on buying supplies and seeds. 


Seedling sprout


Seeds can sometimes be sprouted indoors at this time, but it is probably best to do this indoors to ensure they stay warm enough, ideally between 68 and 75 degrees. However, areas like southern Florida should have no problem with keeping them warm enough at this time. 




March feels like summer in some of the most southern areas of North America. Any risk of frost is gone by this point, and days have reached between 11.5 and 12.5 hours long.


Seeds should be sprouted earlier in the month, taking measures to ensure they receive enough sunlight. Plants that do not get enough sunlight will start to flower, even if they’re tiny. Mother plants being used for clones should be ready by the end of the month.




In April, days are comfortably between 55 and 85 degrees, and most regions will get between 12 and 14 hours of daylight. Most areas will have at least 13 hours of daylight by the end of the month, so supplemental lighting is no longer necessary. 


Plants can start being transitioned to the outdoors. Start by putting them outdoors in a shady area and gradually increase the amount of time they spend in direct sunlight until they are ready for full sun. Growers using a mother plant can start taking clones by the end of the month. 




In May, it is technically still spring but likely feels like summer in most places. Days are long enough to sustain the vegetative stage, as they are around 14 hours long at the beginning of the month. 


Plants are ready to be moved outside permanently. Autoflower seeds should be planted by the second week in May. 




June ushers in the longest days of the year, reaching up to 14.5 hours long. Just like in northern regions, June is when marijuana plants will grow the most. This is also true of autoflowers that were planted in May. Growers must support this heavy vegetative growth with a nitrogen-heavy nutrient schedule. By the end of the month, non-feminized plants may begin to show their sex, so growers need to keep an eye out for male plants.




This is by far the hottest month of the year, with temperatures reaching well into the 90s with some instances of going over 100. Growers must stay on top of watering their plants, as the high heat can dry them out quickly.


Growers that identify male plants in their crops must get rid of them now. Autoflowering plants should be in full bloom, with buds getting much heavier. 




August is still a fairly hot month, with temperatures well into the 90s. Days are between 13 and 14 hours long. Some regions may see plants start to transition into the flowering phase, especially towards the end of the month. 


Weed seasons flowering


Autoflowering plants should be ready to harvest sometime this month, so growers should watch them closely to see when they are finished. Non-autoflowering plants will have more flower growth, with pistils and buds forming rapidly. Growers should be sure to support bloom growth with a nutrient solution heavy in phosphorus. At this point, growers may find their plants giving off a distinct aroma. 




Days start to cool off in September, but they are by no means cold. Temperatures are still between 65 and 90 degrees in most places, but the days are usually only 12 to 13 hours long. By the end of the month, many plants will be ready to harvest. In the meantime, growers must keep watch for bud rot, especially if it is a humid area like the southeast United States. 




Once October arrives, the average day in southern regions is less than 12 hours. The temperature can still be fairly warm, going as high as the mid-80s. Plants should all be ready to harvest by this time. 


Final Thoughts


Weed seasons


Following a marijuana growing calendar when growing marijuana is the best way to ensure a successful harvest. Growers should know the climate of the region they intend to grow and plan accordingly.

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