cannabis grow calendar

The Cannabis Cultivation Timeline

An overview of the 5 stages of cannabis cultivation.

  • 1. Getting started
  • 1.a. Photoperiod plants
  • 1.b. Autoflowering plants
  • 2. 5 stages of cannabis cultivation
  • 2.a. Stage 1: germination — 1–7 days
  • 2.b. Stage 2: seedling — 2 weeks
  • 2.c. Stage 3: vegetative phase — 2–8+ weeks
  • 2.d. Stage 4: flowering — 6–12 weeks
  • 2.e. Stage 5: harvest, trimming, drying and curing — 1–2 months
  • 1. Getting started
  • 1.a. Photoperiod plants
  • 1.b. Autoflowering plants
  • 2. 5 stages of cannabis cultivation
  • 2.a. Stage 1: germination — 1–7 days
  • 2.b. Stage 2: seedling — 2 weeks
  • 2.c. Stage 3: vegetative phase — 2–8+ weeks
  • 2.d. Stage 4: flowering — 6–12 weeks
  • 2.e. Stage 5: harvest, trimming, drying and curing — 1–2 months

Growing cannabis comes with a lot of uncertainties. That said, cannabis cultivation itself can be broken down into five distinct stages, regardless of which seeds you’ve selected.


Before you just start throwing seeds into soil, consider what kind of grower you want to be. Are you running an indoor operation, or working in the great outdoors? Do you have the supplies fit for your growing environment? Have you made sure to pick seeds that’ll thrive where you’re planting them, indoors or out? Speaking on that last point, any aspiring grower should know the difference between photoperiod and autoflowering cannabis plants. There are a few key differences to note.


The main marker of a photoperiod plant is the potential for indefinite vegetation—as long as you keep the plants on an 18/6–24/0 light/dark cycle. We’ll talk more about that later, but it means these plants can withstand more mistakes in the growing process. It also means you can ensure your plant produces the best crop possible once you initiate flowering. All you need to do to make the switch is adjust the light cycle to 12/12. This becomes even more useful when you’re able to make unlimited clones of your optimised plant. The main drawback is that it’ll take around four months to get a substantial yield. However, you’ll have a larger and usually more potent plant once you’re there.


The way these differ from photoperiod plants is written in the name. Regardless of whether you feel the plant is ready, it’ll start flowering at a certain time depending on the strain’s genetic programming. In one sense, these plants are easier for novice growers because there’s less to think about in regards to light coverage and cycle adjustment. On the other hand, due to the limited vegetation time, you have fewer opportunities for mistakes. This isn’t ideal for first-timers, but the fact that it only takes two months from germination to harvest is definitely appealing. Autos tend to produce lower, milder yields than their photoperiod counterparts, but modern advances are bridging the gap.


Now that you’re familiar with the distinctions between photoperiod and autoflowering strains, we can begin to break down each stage involved in cannabis cultivation.


Even when your plant is a mere seed, the work you put in will dictate its success or failure. Germination is the stage when the first root cracks out of the seed’s shell, which takes between 1–7 days. The wet paper towel method is a classic approach here, but you start out with the major setback of tiny fibres all over your new root. You can plant directly in the soil, of course, but you need to ensure temperature and moisture are dialled in.

If you want to keep all your seeds safe and clean, we recommend the Royal Queen Seeds Starter Kit. With that, they can enjoy clean, undisturbed germination. Once they get to 2–3cm high, you can remove them from the starter and place them in a suitable growing container.


Breaking through the germination stage, plants enter the seedling stage next. At this point, they’ll need about 18 or more hours of daily light. After two or so weeks of proper care, though, they’ll be well on their way to robust growth.

This is the point where it starts to look more like a cannabis plant. There will be one ridged blade per leaf at first, but the blades will get closer to their typical 5–7-finger stage by the end of this period. Until they get the full 5–7 blades, though, the plants are considered seedlings. Along with the increasing blade count, a vibrant green colour is another mark of a healthy plant. To keep them healthy, the two main things to keep an eye on are water and cleanliness. Seedlings are still fragile, so only light watering is necessary. Cleanliness is equally vital due to their disease and mould vulnerability. The perfect home for cannabis seedlings is a propagator, ideally with 70% RH and temps 20-25°C, under either white CFL lights or LED’s.


Vegetative growth is normally associated with a transplant at some point as plants outgrow the starter medium be it a Rockwool block or paper cup filled with soil or coco. Continued development of the root zone and robust branching are the top priorities for the grower. High RH of 50% is ideal and cooler temps 20-24°C can promote more females if growing regular seeds.

Autoflower cultivators have even less time to play with than photoperiod growers as most autos will race into flowering after just 2-3 weeks of vegetative growth. It’s for this reason that many auto growers plant their autoflowering seeds directly into the final container. The clock is ticking with autos from the moment of germination.

Photoperiod strains can be kept in vegetative growth indefinitely so long as 18+ hours of light and suitable conditions prevail. This is what allows indoor growers to keep mother plants for years and why outdoor grower’s plant in springtime. Indoors or outdoors 18+ hours of light facilitates taking cuttings too.

This is the stage to pot up photoperiod plants into final containers, at least a couple weeks before switching to bloom or prior to Summer outdoors.

While the photoperiod strains can be kept in veg weeks or even months to allow for all kinds of pruning and training to boost yield like topping, FIM, LST or even a ScrOG the Auto grower is somewhat limited by time.


At this stage, the focus of the grower and plants switches to the production of buds and the grower is already dreaming of a frosty marijuana harvest in the near future. RH needs to be reduced to 40-50% and temps kept between 20-28°C.

Cannabis plants will first give you an indication of their sex in the early phase of bloom. Typically within the first two weeks of flowering females will develop pistils or “hairs” to confirm their femininity.

If you see “nanners” or anything resembling a cluster of grapes protruding from flowers or anywhere on the stem then you have a male cannabis plant. Should you see both hairs and nanners then you have a hermie to remove right away.

Photoperiod strains are induced to bloom by the hours of light they receive; indoors the grower changes to a 12-12 light-dark cycle to artificially promote flower growth.

Outdoors Mother Nature dictates the grower’s schedule and flowering will only commence in Summer/Autumn as the hours of daylight naturally diminish, making for a longer more gradual flowering period. Weed growers in the Northern hemisphere don’t refer to October as “Croptober” for nothing.

Of course Autoflowering strains don’t follow the rules due to their Ruderalis genetics, so they will begin to bloom in about a month post-germination. Auto’s prefer to stay in 18+ hours of light for flowering and will be more productive on a light-dark cycle that would inhibit photoperiod strains from blooming at all.

Flowering generally lasts 7-10 weeks for indica and hybrid photoperiod cannabis strains, while the more Sativa dominant strains can take 10-14 weeks to fully ripen into primo head stash.

Autos really only flower for 30-45 days with a much more sudden transition into flowering, choosing feminised autos is a wise choice for novices that don’t want a seeded stash.

It’s always best to evaluate if a cannabis plant is ready to harvest by taking a closer look at those resin dripping buds. Using an inexpensive scope to zoom in on those resin heads to make sure they are milky and amber rather than clear removes all the guess work.

Once you confirm you’ve got a ripe marijuana crop on your hands it’s time to break out the trimming scissors and get harvesting. After two weeks slow drying in paper bags or hung up, at room temp and approximately 50% RH, you’ve got a stash.



Harvesting is the most rewarding part of the cultivation process for many growers. Watching your plants grow over several months is mesmerising, but finally harvesting the fruits of your labour truly is the peak of the experience. The flowering phase of the grow cycle typically lasts between 7–11 weeks, after which it’s time to strip your plants down of their buds. However, you don’t want to do this too early and prevent your flowers from fully maturing. Likewise, you don’t want to wait too long. Timing harvest is a crucial step, and there are multiple signs you should look out for to know when the time is right.

One of the best ways to truly tell if your flowers are ready for harvest is by getting up close and personal with a magnifying device. This visual advantage will enable you to detect minor changes that wouldn’t be noticeable to the naked eye. Some growers choose to use a jeweler’s loupe, which is essentially a pocket-sized magnifying glass encased in a piece of metal. Others choose to use devices such as digital microscopes, which provide greater detail.

Ultimately, the most important use for your magnifying glass is to detect the progress of your trichomes, and therefore, the proper time to harvest your buds. Trichomes are small mushroom-shaped glands that produce resin which contains the vast majority of cannabinoids and terpenes.

Looking for shifts in trichome appearance is the most accurate way to determine the stage of maturity of your crop. Trichomes are hard to miss and appear as a white frosty substance that covers the buds and sugar leaves. Zooming in on these structures will allow you to know how far along your plants are, and whether they are ready for the chop.

Earlier on in the flowering phase, trichomes will appear translucent, meaning they are still developing and should be left to mature. When approximately 60% of the trichomes develop a milky look, they are ready to harvest. It’s at this stage where they will produce the most significant high . However, some growers wait until up to 90% of trichomes move past this milky look and become amber, as this will cause the buds to develop a more stoning and sedating effect.

Another sign that your buds are maturing is when the pistils of the flowers change colour. Pistils are small-hair like structures that grow out of the calyxes, and are the reproductive organs of the female cannabis plant. They are the site where pollination occurs—if male pollen were allowed to land there. Pistils appear bright white during the early stage of the grow cycle, and eventually shift to an orange-brown colour.

Aside from the buds themselves, another way you can tell your plant is approaching harvest is by examining the colour of the leaves. Provided you haven’t overfed your plants during the final stage of flowering, a yellowing of the leaves will signal that your plant is reaching peak maturity, and that its nutrients are being fully utilised by the buds. By flushing out nutrient salt buildup with pH-balanced water for a couple weeks before harvest, a smoother, more pleasant smoke is guaranteed from each plant.

Now that you know when to start harvesting your buds, it’s time to learn how to trim them.


You can trim your cannabis plants in one of two ways: wet or dry. Both have their own advantages, and each grower will differ in which one they prefer. Wet trimming refers to trimming off the sugar leaves surrounding the buds immediately after harvest while the plant still has a high water content and feels “wet”. This method is the most common, and arguably the easiest, as it doesn’t require a large room to dry out plants beforehand. However, wet trimming is literally sticky business. The resin from the flowers will cover both your hands and your scissors, but there is an upside to this. By scraping the resin from your scissors every now and then, you’ll quickly build up a supply of “scissor hash”, allowing you an early taste of your harvest.


Dry trimming takes place after your entire stash has been dried, and little water content remains within the buds and leaves. Trimming dry buds is definitely easier on your scissors since they won’t become as inundated by clumps of resin. However, accurately manicuring dry buds can be somewhat of a hassle too, making for a potentially less visually appealing final product. Moreover, dry trimming does require a fair bit of space. Growers usually hang entire branches of buds from a line of string within temperature-controlled rooms to let them air-out until sufficiently dry.


Now that harvesting and trimming are complete, it’s time to cure your flowers. Curing is an essential process that removes the last of the residual water from the buds, minimising the chance of mould and greatly prolonging shelf life. Curing also enhances the taste and quality of the smoke, making for a smooth and potent experience.

If you opted to use the dry trimming method, then your flowers will be ready to cure straight away. If you chose wet trimming, then your flowers will need to be properly dried before you go on to cure them.

  • To do this, spread them out over some cardboard, newspaper, or, even better, a wire drying rack. Whichever you choose, make sure they are spread out over a large surface area and exposed to as much fresh air as possible. Aim for a steady room temperature of 21°C and a relative humidity of 50% to ensure a longer but gentle drying process to maintain as much flavour as possible.
  • Now we can move on to curing. For this, you’ll need airtight glass jars to minimise mould from taking hold. Fill each jar so it’s ⅔ full, leaving adequate room for air. This is the perfect environment for excess sugars and chlorophyll to be broken down, a process which is key for those smoother hits of smoke.
  • For the first two weeks of curing, open each jar once or twice per day and remove each bud, checking for any signs of cobweb-like mould. If you detect anything, remove this bud from the jar and place it in the bin. Opening jars this regularly will also serve to replace the air within the jar, keeping it fresh.
  • After a few weeks, the need to check your buds as much will reduce; the drier they become, the less chance there is of mould striking. At this stage, you’ll only need to check around twice per week to expose your buds to fresh air. After a few weeks, your buds will be cured; however, some growers choose to go a few weeks further to develop pristine and high-quality flavour. You can smoke-test you buds as the weeks go by to see if the current taste suits your preference.

For more info on drying and curing your herb, check our blogs Top Tips To Successfully Dry And Cure Your Fresh Cannabis Buds and How to Cure Your Cannabis Buds.

Royal Queen Seeds produces some of europe’s best cannabis seeds, ensuring hobby growers everywhere have access to the finest marijuana strains around.

Royal Queen Seeds produces some of europe’s best cannabis seeds, ensuring hobby growers everywhere have access to the finest marijuana strains around.

From germination to curing, understanding each stage of the cannabis growth cycle is vital to achieving a healthy cannabis crop.

Grow Calendar For Northern And Southern Europe

Zamnesia wants to make sure you get your timing and species selection spot-on to produce luscious crops every grow season. Whether you live in Northern or Southern Europe, let us help you germinate at the right time for vigorous vegetation and big yields.

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Choosing the right strain for your climate also plays an important role, and we have got you covered there as well. Following these general guidelines will get you plenty of sticky icky in the jar come harvest time, while avoiding weak germination, poor vegetation, fluffy buds, low yields, and dreaded pathogens.


Choose An Appropriate Strain

It goes without saying that different cannabis strains display different characteristics. They look different as they grow, have differing bouquets, and a wide range of effects. Depending on the growing climate, strain selection can involve more than phenotype, flavour, and effect. Cool, wet climates with short days demand a more hardy selection that flowers quickly, while warm and humid coastal areas can sustain strains that enjoy a lot of sun and flower over a longer period.

When To Purchase Your Seeds

Whether you are in the North or the South, or if you are using supplemental lighting to extend the vegetative phase, buying and germinating seeds is purely academic. You could get underway in the middle of winter and have quite large plants to put outside once the days lengthen, or only germinate the month before they are to go outside, just to get a head start. It entirely depends on the available growing space. And then there are greenhouses.

For the purist who wants to follow the timetable nature has set, and lives in Northern Europe, buying seeds in late April for germination in May will ensure plants receive plenty of light for proper vegetation.

Wind the clock back a month for those in the Southern climes. Allowing time for delivery, purchase seeds ready for germination as the rest of nature stirs in response to spring; buy late March and early April for a germination in April.

Be part of an age-old debate among outdoor and indoor growers alike: Does the full moon and planting time have an effect on plant quality? Some say it doesn’t matter—cannabis is a very vigorous plant and will grow under any circumstances. Others claim that planting 4 days to a week before a full moon increases the germination rate and produces a more robust plant with more vigorous growth. If you have the room, try comparing plants germinated 1 week after the full moon to others germinated 1 week before. Even under lights. Develop your own lore.

Northern Climates – Cool Northern Latitudes

Northern climates are typified by cooler average temperatures, shorter days, and shorter growing seasons. There are a number of species of cannabis that have been developed to thrive in the challenging Northern environment. Species with short flowering times or those with autoflowering genetics can be ready for harvest much sooner than many standard photoperiod strains.

With cooler air and less evaporative sunshine, strains with a high mould resistance will get to full maturity with less susceptibility. Strains with a heritage in the mountains and a naturally high tolerance to cold will also do better than those with tropical heritage.

Suggested Strains For Growing In Northern Climates

Indicas and indica-dominant strains are your friends in Northern Europe, as are autoflowering strains. Since the cannabis diaspora over 12,000 years ago, indicas have developed genetic characteristics dictated by their evolution in cool mountain regions with early, then intense winters, and short summers.

Autoflowering strains have a number of advantages, with one of them being that an extra crop can be harvested per year, thanks to the ruderalis genetics. This subspecies evolved in Central Asia, where cold tolerance and early propagation opportunities were a distinct advantage. Indica autoflowers get a double whammy of cold tolerance and quick-flowering genetics.

Southern Climates – Hot, Dry Interior, And Warm, Wet & Humid Coastal Climates

Southern climates are typified by warmer average temperatures, longer days, and longer growing seasons. Cannabis originally evolved in these types of climates before it was spread all over the world. There is something deep in cannabis genetics that makes it thrive in warm, sunny, and humid climates.

All species of cannabis will respond with vibrant life in warmer and sunnier climates. Species that need a long growing season to reach maturity can be grown more successfully the closer to the equator you get. Grows in humid or rainy environments will benefit from mould-resistant varieties. Warmth always means more bugs, so strains with a combination of resistance to pathogens and insects are always the least troublesome.

Suggested Strains For Growing In Southern Climates

Growers in hot and dry microclimates will be able to grow whatever they like really. Most sativas a very tolerant to direct sunlight, where other species will perform better when shaded. Contemporary sativa-dominant hybrids can be grown for all the sativa benefits, with flowering time sped up significantly. Autoflowers will stretch and fill out more under the more intense sunlight and longer days. All species will generally display larger overall size and volume, with more stretch during vegetation.

Humid southern coastal microclimates still get the benefits of lots of sun. Humidity can be a challenge, especially during flowering when thickening flowers can become susceptible to mould and other pathogens. Mould resistance is usually a feature of heavy resin production, which has the added benefit of providing pest resistance. Choosing mould-resistant strains will prevent the heartache of bud rot, especially if an area gets sea mist, fog, and regular rainfall.

When Is The Calendar Not The Calendar?

Artificially extending the daylight period of plants grown outside with supplemental lighting for up to 18 hours means that when natural springtime comes along, plants will already be substantially advanced, and in some cases—when there are facilities available—can reach 5–10 metres tall. This isn’t for everyone as it depends on a country’s laws and having the space or the facilities to pull it off. Nice to dream though—mmh, ten metre cannabis trees!

A Quick Note On Greenhouses

What’s green and shaped like a house? Not a greenhouse, but a quick note on greenhouses. Greenhouses, especially if you are allowed by law to grow weed, can be the best of both indoor and outdoor worlds. When protection from harsh trichome-withering weather and modification of the immediate environment and photoperiod are required, a greenhouse can be your best friend. Greenhouses are an especially welcome grow setup in northern climates. Even so in the south, but they can be a challenge to cool in the height of summer.

Outdoor Cannabis Grow Calendar For Northern Europe

Every outdoor cannabis grower relies on accurate climate data and weather forecasts to plan a crop from seed to harvest. This coming growing season, ganja farmers in the Netherlands and surrounding countries will rise to the challenges of cultivation in an oceanic climate. We have created this grow calendar as a roadmap specifically for the Northern European cannabis road warriors.


Day length: 9.05 – 10.47 hours

Average temperature: 2.5 °C

February is far too cold and dark to rush outside and start sowing seeds in the dirt. Temperatures will be close to freezing by day, and may dip below zero overnight. The online climate charts will tell you to expect approximately 10 hours of sunlight this month. In reality, you won’t see much sunshine through overcast skies. There is also still a significant risk of snowfall. This is the month to research cannabis seed genetics, weather forecasts, and to gather supplies. Most of the essentials like soil and fertilisers can be found online. But it may take a couple of weeks before all the deliveries arrive.


Day length: 10.51 – 12.52 hours

Average temperature: 4.7 °C

Still too cold outside. Probably pretty cloudy most days as well. But you can kick-start the grow like a pro indoors. By now, you should be in possession of all the outdoor cultivation essentials. With a minimal investment, you can acquire a basic CFL lamp and reflector to start seedlings indoors. Whether you are growing from seed or using clones from a trusted source, it helps to get plants rooted before you put them outside.


Day length: 12.56 – 14.48 hours

Average temperature: 8.2 °C

By the middle of the month as daily sunlight increases to about 14 hours, you can begin to make a move outside with plants in 10–20l pots. Temperatures will be in the low teens at best, so only the strong will survive outside this early. Hardy autoflowering strains are definitely the best option. Blue Cheese Automatic by RQS or Early Skunk by Sweet Seeds are rapid bloomers and cold-weather-hardened.

Although tough photoperiod hybrids like Durban Poison by Sensi Seeds or White Critical Express by Kalashnikov Seeds will receive sufficient sunlight for vigorous vegetative growth, late-blooming sativas are to be avoided as the growing season is just not long enough in northern latitudes. Old-school Holland’s Hope and Early Girl will perform well in a greenhouse. But if you want high-grade weed, you need to be a little more patient.

Day length: 14.52 – 16.20 hours

Average temperature: 12.3 °C

Purists can germinate seeds and start them on a sunny windowsill. As daily sunlight reaches 15 hours and the temperatures stay consistently in the low-mid-teens, it’s finally the right time for most to grow outdoors. Fast-flowering strains are still the best choice. Classic Skunk and Northern Lights by Zamnesia Seeds are solid choices. Alternatively, you can start a dank super auto like Royal Gorilla Automatic by RQS or Devil Cream Auto by Sweet Seeds.

However, if you got started inside, May is the month to harden off and make a move. Start by potting up to large 10–20l final containers. Use your artificial light to supplement the hours of natural sunlight. Using pots allows you to move plants in and out. By the end of the month, they are ready to grow outside permanently.

Day length: 16.22 – 16.38 hours

Average temperature: 15.2 °C

With a little luck, temperatures will be in the high teens, and by the summer solstice on the 21st, daily sunlight will peak at 16 hours and 38 minutes. Autos germinated in March/April will be ready for harvest this month. Provided they have been sheltered from rain, the buds will be of respectable quality and a decent yield can be expected. Photoperiod strains will vegetate comfortably and still have enough time to grow to large sizes and yield heavily.

Day length: 16.37 – 15.29 hours

Average temperature: 16.9 °C

Sun-flowered autos started in May will be ready for the chop this month. You could potentially be harvesting your second crop if you get your timing right and selected the right genetics. Most photoperiod strains will still be in vegetative growth and it could be time to do some pruning and training if plants are beginning to turn into trees. Temperatures in the low 20s and 15+ hours of sunlight are great conditions for growing cannabis.


Day length: 15.26 – 13.37 hours

Average temperature: 16.7 °C

Photoperiod strains will begin slowly transitioning to the bloom phase this month. And if you got a late start with your autos, don’t fret; you still have time to finish flowering this month. By the end of the month, you are back down to about 13.5 hours of sunlight per day. This is not a perfect 12-12 light-dark cycle and is the reason why photoperiod strains take far longer to bloom outdoors. If you have a greenhouse, you can cover it over with light-proof sheeting to reduce the hours of natural light and speed up flowering.


Day length: 13.34 – 11.39 hours

Average temperature: 14.2 °C

If you haven’t already, now is a great time to build a simple shelter for cannabis plants in mid-late bloom. Heavy rainfall is not uncommon in September. Daily sunlight will decrease from 13 hours and 34 minutes to 11 hours and 39 minutes in 30 days. Be on the lookout for threats to the buds. High humidity and decreasing temperatures to the low teens are a recipe for bud rot. Better to harvest a little early than to lose the crop. Photoperiod plants should be harvested towards the end of the month. September is potentially a third auto harvest month. Autos sprouted in June/July will certainly be ready.


Day length: 11.35 – 9.38 hours

Average temperature: 10 °C

You had better be close to the finish line to be still growing this late in the year. Temperatures will be 10°C at best and sunlight is fading fast. By Halloween, daily sunlight hours will be back down to single digits. Get trimming and harvest as soon as you can. Winter is coming! November, December, and January are months for hibernating with a fat stash.

Grow Calendar For Southern Europe

Cannabis, like most plants on earth, germinates and begins growth at the beginning of spring. Celestially speaking, no matter what the actual date is on a calendar, spring is considered to begin around the full moon of March or the Vernal Equinox.

This doesn’t mean that spring signals “germinate some seeds and go” everywhere simultaneously. When cannabis is germinated too early, or when the daylight hours are still below 12 hours, seeds will still germinate, then show sex early and continue to grow into a lovely plant. However, at the important bud stage, they will be fluffy and poorly formed and have disappointing yields. It is tempting to try and get ahead of the curve by planting early, but it always leads to disappointment in the end.

Although frustrating, it is better to wait later in the season until the daylight is at least 12 hours. You will have a slightly smaller plant, but with a considerably heavier yield of much better formed buds.


Day length: 9:50–11:02 hours

Average temperature: 3–13°C

In February, the days are too short and temperatures still too cold for natural germination. If you have a greenhouse and some supplemental lighting, it is a good time to germinate. Once the plants are established and well-rooted, they will be ready to be put outside to harden off once the weather starts to warm and the days get longer.

February should be spent preparing pots or giving organic gardens a final amendment and mulching. Seeds can be bought in preparation for the oncoming growing season. Be sure to read the breeder’s stats to guarantee you get a strain suited to your circumstances.


Day length: 11:05–12:34 hours

Average temperature: 5–16°C

Time to start germinating your seeds. Some supplemental lighting is still required to assure over 12 hour long days. If you have mother plants, it is time to start preparing them and making clones. By the end of the month, it will be time to put established clones outdoors to enjoy the longer days.

If you are planning on staggering a number of autoflowering varieties for multiple harvests over the coming months, get your first batch going now too; they will be ready mid to late May.


Day length: 12:37–13:59 hours

Average temperature: 8–19°C

A day length of over 12 hours means no more need for artificial lighting. Plants will germinate in their pots and begin vegetation outdoors. Once the first set of true leaves emerge, growth is noticeable on a daily basis. Putting plants in a place that gets maximum sunlight per day and good air circulation will guarantee optimal growth and vibrant plant health. Begin spraying weekly with a natural insect repellent like neem oil to keep predators in check. Autoflowers planted now will be ready mid to late June.

Day length: 14:02–15:06 hours

Average temperature: 13–23°C

Plants will now be happy and enjoying the longer days and warmer temperatures. Growth will be speeding up, the leaf sizes will be getting larger, and the plant volume will be increasing. Check soil moisture more often; as plants increase in size, they use more water per day.

Germinating autoflowering strains now means a solid 3 months of ideal growing weather. They will completely fulfil their genetic potential and be ready mid to late July. Autos planted in March will be ready for harvesting now.

Day length: 15:08–15:23 hours

Average temperature: 14–28°C

Now we are in the sweet spot. Sunlight is at its maximum strength, days are at their longest, and temperatures are in the ideal cannabis growing range. Vegetation will be in top gear. Check soil moisture content more often, as evaporation and transpiration are at their max. Organic and no-till gardeners should be watering with compost teas and other supplements now.

Check the soil temperature—especially in plastic pots—as the days get longer and warmer. Use shade cloth or a cardboard sleeve to protect the pot walls and make sure the top is well mulched. Overly warm substrates encourage root rot, root pests, and slow growth. Plants can show signs of stress like wilting, slow development, and nutrient problems. Poor plant health can attract unwanted pests.

Day length: 15:22–14:39 hours

Average temperature: 17–31°C

Still in the sweet spot. The day length is starting to shorten, but the temperatures will still remain high. Early-flowering and feminized varieties will start to show pistils. Regular photoperiod plants may be starting to show sex also. Identify and remove males, or isolate them if you are going to be doing some breeding. Continue to check soil moisture and temperatures and maintain pest control methods. Autoflowers germinated back in May will be ready for harvest or fattening up in the last stages of maturity.


Day length: 14:39–13:35 hours

Average temperature 17–31°C

Longer-flowering autoflower varieties planted in May will be ready for harvesting now. Quicker-flowering cultivars will be filling out substantially. Regular photoperiod plants will have completely established sex by now, displaying small flower clusters with many pistils at each node. Differentiation will have occurred with longer-flowering varieties. Nodes will begin to stagger rather than being symmetrical about the stem. The ends of branches turn up, where the main bud will form and begin to fill out. They will be getting ready for the bloom stretch at this stage.

There is still time to get a reasonable autoflower crop if planting now. Plants will be smaller than those planted before summer, but not disappointing.


Day length: 13:30–11:54 hours

Average temperature: 14–26°C

Many quicker-flowering and feminized varieties will be ready for harvest between the middle and end of this month. The flowering stretch for regular varieties is well underway and plants may double or even triple in size over the next two months. Buds are nearing their full potential size, but are yet to fill out properly. Aromas are beginning to develop, and trichomes are proliferating quickly on calyxes and sugar leaves. Profit-yielding varieties will need staking to support weighty flowers.

At the end of this month, larger plants can have their upper, more mature buds harvested, allowing more light penetration into the lower parts of the plant. A multi-stage harvest on larger plants will allow for even maturation and bud quality.

With seasonal rains at the end of summer, it is time to be vigilant for pathogens. As buds fatten, they can become susceptible to diseases like Botrytis if they remain wet for too long.


Day length: 11:51–10:56 hours

Average temperature: 11–21°C

This is the month when things really get exciting. Calyxes begin to fatten properly and pistils start to change colour and die back. Trichomes are starting to swell toward maturity and fragrances are at an all-time high. Purple and blue strains will be getting darker as the weather cools. Exhausted leaves from the lower reaches of plants will yellow, wilt, and drop off.

Most varieties will be ready halfway through or by the end of this month. Watch trichome colour closely for an indication of harvest time.

The final autoflower crop of the year will be brought in now. Unless you have a greenhouse and supplemental lighting, don’t plant any more autos.


Day length: 10:23–9:17 hours

Average temperature: 6–16°C

Long-maturing landraces or sativas like Haze varieties will be ready for harvest this month. The wait and patience will be well-rewarded as you dismember giant trees with a maniacal smile and a sense of great satisfaction.

Make sure you get the heaviest yields by following the Zamnesia grow calendar for Northern and Southern Europe. Know when to germinate and when to harvest.