USA cannabis growers enjoy great conditions to grow high quality outdoor weed no matter which state they grow in. But the wide variation in local climates means that care needs to be taken to ensure the best cannabis seed varieties are matched to the right region. Autoflower seed varieties can be grown in all states, and in states like Alaska they may be the only realistic choice.

Summary:

• Growing feminized photoperiod seeds outdoors
• Key tips & tricks for outdoor and guerrilla growers in the USA
• How to pick the right cannabis seeds for your climate
• Climates guide for outdoor cannabis growers in the U.S.
  • Humid continental (cool summer)
  • Humid continental (warm summer)
  • Humid Subtropical
  • Tropical wet/dry season
  • Semi-arid Steppe
  • Highland
  • Midlatitude Desert
  • California
  • Marine West coast
• Key takeaways for outdoor growers in the U.S.

Different climate zones of the USA

Important information when growing dedicated feminized cannabis seed varieties outdoors

Most outdoor photoperiod feminized cannabis seed varieties start blooming when days shorten in summer to around 14 - 14.5 hours of daily light (or less). This is usually their trigger point to start flowering. They are ready to harvest around 2 - 2.5 months later.

When you want to grow specialist indoor feminized seed varieties outdoors, the trigger point for bloom regarding daylight hours is usually a lot lower, closer to 12/12 (12 hours of daylight, 12 hours of darkness). Some strains might start flowering at 13 hours. But this delayed/late trigger point makes these strains less suitable for outdoor growing. That’s because bloom may simply start too late, with punishing late-season weather preventing your buds ripening.

Check your climate and daily light hours through the grow season. It is important to note that not all 'indoor' varieties will finish in time, depending on your location. The right choice will mostly depend on the given climate during the growing season in your specific region.

This delayed/late bloom point makes dedicated ‘indoor’ strains less suitable for outdoor growing, unless advised differently. But such varieties can be useful to those growing outdoors near the equator, where around 12 hours of daily light is normal all year-round. However, in these cases care is required when selecting your cannabis seed varieties.

That’s because a compact indica dominant strain, such as Kerosene Krash may well experience issues (mold, rot etc) when grown in a wet tropical climate. But a proven high-quality sativa such as Desfrán would be better genetically suited and a safer choice.

Key tips & tricks for outdoor and guerrilla growers in the USA

Think Fast feminized cannabis seeds grown outdoors in guerilla

USA outdoor cannabis growers have various options which can be used to great advantage: 

•   Germinating and growing cannabis seeds indoors until the outdoor weather has warmed up sufficiently can offer a significant head-start for your plants. This should mean heavier eventual yields. This technique can be used for any cannabis seed variety - autoflower seeds, feminized seeds or fast feminized seeds (described in detail later).

•   Use of poly tunnels and greenhouses mitigates the effects of adverse outdoor weather. This protects your plants from the worst of the early/late season weather - allowing superior growth rates and effectively extending the length of your grow season. Greenhouse growers also have the option to install supplemental LED lighting which auto-adjusts to top-up light levels on cloudy days. This can really boost yields and help maximize quality/THC levels.

•   Those expecting severe late-season weather may be able to partially protect their plants from the worst of the rain by erecting e.g. a tarpaulin shelter to prevent their prize blooms getting drenched and risking subsequent bud-rot. Use of autoflower seeds or fast feminized seed varieties can also be a genuine game-changer for US outdoor growers who routinely struggle with cold, wet fall weather. Harvest your buds earlier instead!

•   By definition, outdoor growing can occasionally challenge the grower with unexpected storms and some years where fall arrives earlier than usual. Extreme summer heat is becoming an increasing issue in many states. Use of both autoflower seeds & fast feminized seed varieties alongside traditional feminized seeds allows the discerning grower the chance to harvest at several times throughout the year.

•   Whilst no outdoor grower is guaranteed success, these tips can maximize your chances. The following outdoor/guerrilla grow guide was created for UK outdoor growers around latitude 50-55. The tips and grow advice are especially relevant for growers in far northern States with short damp/cool/grey summers.

Related:
How to acclimatize indoor-grown cannabis plants for outdoor growth

How to pick the right cannabis seeds for your climate

Pamir Gold feminized cannabis seeds grown 6890 feet above sea level (450g-harvest)

One of the most important considerations for your specific outdoor grow conditions is understanding the amount/availability of daily light during the season. This directly impacts your cannabis seed choices. Three of the main questions you face are:

• When will it be warm & sunny enough for plants to grow vegetatively outdoors?
• When will the cannabis bloom phase start?
• When will my plant be ready to harvest?

The USA has several broad climate zones which we discuss below. But also be aware that the presence of local mountains, oceans, lakes or even a walled-garden can impact your own local micro-climate. Sometimes significantly. 

In other words, it may take a season or two before you fully understand the intricacies of your local conditions and which cannabis seed varieties best suit you. Here are your three main seed options.

Photoperiod feminized seed varieties grow over a roughly 5-6 month period from spring to fall. Their initial vegetative growth phase allows branches, leaves and roots (but no buds) to grow. The cannabis bloom phase only sets in once daylight hours shorten sufficiently. 

As the cannabis plant senses the onset of shorter days hormonal changes start the process of flowering. The exact date depends on your latitude, climate and strain. But many feminized seed varieties start to bloom around August and finish during late September or October. 

Longer blooming sativa/Haze cannabis seed varieties may only be ripe around November, too late for many northern US growers. This means that you need to know the realistic length of your grow season and select the most appropriate strains. 

Outdoor yields can vary from 5-10oz to 3-4lbs+ per plant. Much depends on climate, feminized seed type, soil conditions etc.

Autoflower seeds have a short life cycle, around 3-4 months outdoors. This means that autoflower seeds are suitable for growers in all US regions. Even Alaska, where the long summer days (20+hours of sun) are ideal for autos in bloom. Note that autoflower seeds do not need short (12 hour) days to bloom. Instead, they start to bloom automatically (hence the ‘autoflower’ name) once they are around around a month old.

In mid-level states two successive outdoor crops per year may be possible. In southern states such as Florida, Texas, Southern Cali etc, it may be possible to finish 3 successive outdoor auto crops each year. Outdoors, autos yield anywhere from 1-10oz.

Autoflower seeds, just like feminized seeds, can be germinated and initially grown indoors under 18-24 hours of daily indoor light for a few weeks before being placed outdoors. This allows them optimized early growth and subsequently larger outdoor yields.

Despite being relatively new to many outdoor growers, autoflower seed varieties are especially easy to grow, fast (3-4 months outdoors), offer 20%+ THC levels and account for around half of all seeds sold by Dutch Passion. They are a solid mainstream choice and very reliable.

‘Fast feminized’ seed varieties typically start bloom around a month earlier than traditional photoperiod feminized seed varieties thanks to their recessive autoflower genetics. Fast feminized seed varieties such as Think Fast and GMO Fast are highly recommended for US outdoor growers.

They often bloom around 4-5 weeks earlier than feminized strains when daylight hours are approx 15 - 15.5 hours per day. The early finish means that stable, fast-feminized seeds can be a genuine game-changer for those with borderline climates in fall.

Fast feminized seed varieties grow like traditional feminized seed varieties but the addition of recessive autoflower genetics allows them to breeze through their life cycle faster & earlier than traditional feminized strains, meaning a total life cycle of around 4-5 months.

With this inbuilt genetic speed-advantage, fast feminized seed varieties are ready to harvest around September and are particularly popular with growers that live in states with unpredictable fall weather.

Yields are often 5oz-2lbs approx. The shorter life cycle infers slightly lower yields from fast feminized seeds vs feminized seeds. As always, much depends on grow conditions, plant care, soil, temperatures and sunlight levels.

Climates guide for outdoor cannabis growers in the U.S.

Humid Continental (cool summer, similar to Northern-Europe/Scandinavia)

Eastern parts of North/South Dakota, Minnesota, North Wisconsin, North Michigan, New York, Massachusetts, Maine.

Using Minneapolis as an example, daily light hours shorten below 14 hours in mid-August.

Climate specs and key takeaways for cannabis growers:

With growing conditions not dis-similar to Northern Europe & Scandinavia, those varieties which are ready to harvest early are the most popular. This allows the grower to harvest their plants before the onset of cold/wet fall conditions.

Autoflower seed varieties are particularly recommended. Just pick warmest/sunniest 3-month grow window and germinate your seeds once the weather is sufficiently warm for outdoor life. Germinating your cannabis seeds indoors and giving them a few weeks of indoor growth under artificial lights gives them a head start under ideal conditions. Often this results in faster initial plant development and heavier eventual outdoor yields.

Bonus tips:

• Aerated grow containers such as Airpots, Smartpots, root pouches etc are especially recommended to outdoor growers who don’t root their plants directly into the ground.
• When growing in a greenhouse make sure there is ventilation, possibly a dehumidifier and additional lights - useful advice to greenhouse cannabis growers in all regions.
• Greenhouse growers can use light deprivation (greenhouse black-out blinds) to create the short daily light hours needed to initiate bloom early, if required. Again, this advice works well for greenhouse cannabis growers in all states.
• Don’t expect dedicated indoor cannabis seed varieties to grow well outdoors in these climates.
• Autoflowers seed varieties will grow very well during the June/July/August months.

Humid Continental (warm summer, similar to Western Europe)

Eastern Nebraska/Eastern Kansas and the band of states (Iowa, Missouri, Illinois, Indiana, West Virginia, Pennsylvania, Massachusetts) east all the way to New York/Washington tend to have a humid continental climate. Using Kansas City as an example, daily light hours shorten to below 14 hours in early August. 

Climate specs and key takeaways for cannabis growers:

In these areas growers may be able to harvest two successive autoflower crops, one crop from spring to summer. The next from summer to fall. However, there are quite some climatic variations, so you must choose your crop cycles with some care, especially in northern areas.

Photoperiod feminized cannabis seed varieties will grow well, more so in southern regions of this climatic zone where conditions may be warmer and possibly drier for more of the season.

Bonus tips:

• Whether growing autoflower seeds or feminized seeds, it can be highly advantageous for the grower to germinate their cannabis seeds indoors and give them a few weeks of indoor light (18-24 hours per day) before gradually acclimatizing and transplanting outdoors. This gives the plants a significant head-start and protects them from the worst of the early season weather while the plants are small and at their most vulnerable. This advice applies to outdoor growers of all types.
• The first autoflower crop can be grown (local climate permitting) from May to June. Some could even start in April. The second crop can be started immediately afterwards and grown from July to September/October.
• Feminized seeds are typically started as soon as the outdoor weather is sufficiently warm, often around May. Harvest is often in September/October.

Humid Subtropical (similar to Mediterranean/North-Africa/Asia)

The humid subtropical zone of the US is the lower right-hand quadrant of the country. This includes much of Texas & Oklahoma, Arkansas, Louisiana, Mississippi, Tennessee, Alabama, Georgia, Florida, South Carolina, North Carolina, Kentucky & Virginia. 

Dallas daily light hours dip below 14 hours-per-day in Mid-July. Meaning that feminized seed varieties will start to bloom much earlier than they would in more northern states. 

Climate specs and key takeaways for cannabis growers:

Conditions are usually warm/hot & sunny with relatively long growing seasons, though clear differences exist so check your local conditions (last spring frost dates etc online).

Although generally great outdoor grow conditions exist throughout the humid subtropical southeast US, there are quite noticeable differences e.g. between northern and southern areas. Those in the northern areas may also wish to consider some of the cannabis seed recommendations mentioned above for the ‘Humid Continental’ zone.

Bonus tips.

Longer blooming Haze and sativa cannabis seeds that may not be fast enough to finish in more northern states may have higher chances of success when grown in the humid sub-tropical area.

Tropical wet/dry season

Some areas in the deep south & Southern Florida experience high temperatures, high humidity and moist tropical-like conditions for many months. Growers in these regions have long grow seasons but the often stormy/wet conditions can present their own challenges to the tropical outdoor grower. The airy bud structure of sativa/sativa-dominant & Haze cannabis seed varieties is more resilient to bud rot/mold and may be particularly useful for those growers for whom bud-rot is an ongoing threat.

Related:
How to grow cannabis outdoors in tropical climates, with troubleshooting guide

Semi-arid Steppe (similar to Central/Eastern Europe – Caucasus region)

This zone extends in a large strip down the central/west of the USA from north to south. In the north this meets the Canadian border. In the south it meets Mexico - this represents a huge variation in temperatures and daylight hours with generally drier conditions than other states. Note that the high-altitude mountain regions in the west, including The Rockies, have their own highland/alpine climate zone with specialist seed recommendations.

States include West Texas, New Mexico, Colorado, Wyoming, Eastern Montana, Idaho and western Washington & Oregon.

Climate specs and key takeaways for cannabis growers:

With such large differences from north to south in temperature & daily light hours, it pays to research strains that will finish in time and suit the conditions. 

Depending on altitude & regional climate conditions a strong recommendation would be specialist high altitude cannabis seed varieties, like Snow Bud and Pamir Gold. Selectively bred over many years in the Dutch Passion 1990’s Swiss Alps project, these strains grow well at altitudes where less-adapted strains simply fail to grow. 

Check out this 1lb Pamir Gold grow review at 6900ft above sea level in the West Colorado Plains.

The southern areas, in particular, of the semi-arid US steppe can get very hot during summer. In the event of extreme heat, experienced outdoor growers protect their plants using shade-netting. Plants that are grown in containers can be moved into a shaded area during the hottest hours rather than left to swelter & droop under the fiercest summer sun. In these cases avoid black-coloured plant containers which heat up to dangerous levels (for the roots) in direct sun.  

Conversely, more northern areas can see the early arrival of cold fall temperatures. Growers in these areas are advised to favor fast feminized seed varieties such as Think Fast & GMO Fast as well as autoflower seeds.

Bonus tips:

Avoid putting young plants out too early during cold weather. Growing outdoors in such conditions means slow progress. Your plants may benefit from a few weeks of early life indoors under artificial light. If planting autoflower seedlings outdoors, avoid doing so in heatwave conditions with strong sun. Such conditions are difficult for young plants to cope with. 

In hot weather, ensure there is sufficient water. Autopot systems (self/automatic watering) can help when growing in containers. If growing outdoors in soil, consider a drip irrigation system to keep the soil moist. TConditions are usually warm/hot & sunny with relatively long growing seasons, though clear differences exist so check your local conditions (last spring frost dates etc online).hese can significantly boost growth rates and final yields.

Highland (Alpine, similar to the European high Alps)

The USA highland region is mainly in two narrow strips in the west running from north to south along the California Sierra mountains and The Rockies. Several thousand feet above sea level and with the obvious challenges of large temperature swings and cool overnight lows, cannabis growing in these regions has real challenges.

Conditions, and the length of your grow season vary drastically from north to south so research your climate well, talking altitude into account. For those with the shortest grow seasons, autoflower seeds may be the smartest choice.

Climate specs and key takeaways for cannabis growers:

High-altitude alpine climates can be tough to grow in. Specialist high-altitude cannabis seeds such as Pamir Gold & Snow Bud are wise selections as are certain sturdy/fast outdoor feminized (and fast feminized) varieties.

The cool conditions outdoors mean that many growers in this region germinate their cannabis seeds indoors and give them a month or two of indoor growth under LED before gradually acclimatizing the plants to outdoor conditions once they are warm enough. This can allow growers to extend the start of their grow season and reap larger harvests.

Raised beds are another wise option. Those growing outdoors in containers may find it useful to insulate the grow container. This can be done by placing their grow container inside a larger container and filling the gap with e.g. glass wool (rock wool) or similar. This helps buffer the root zone against cold evening temperatures (as well as fierce summer heat).

Polytunnels/heated greenhouses provide obvious advantages to growers in the Highland climate zone. Some growers also use light depravation techniques (e.g. blackout blinds in a greenhouse) to force the cannabis bloom phase to start earlier in the season. This allows the plants to be harvested earlier, though yields may be slightly compromised due to the shorter grow cycle.

Midlatitude Desert (similar toCentral Spain/North Africa/Middle East)

The USA mid-latitude desert affects several low-rain, sandy and hot regions in the south-western USA. Summer temperatures can be extreme creating challenges for outdoor cannabis growers. This zone includes Nevada, Southern Utah, Southern Cali & Arizona (excluding the north-east of Arizona).

Las Vegas, one of the larger cities in this zone, experiences sub-14-hour daylight from the end of July.

Climate specs and key takeaways for cannabis growers:

With low rainfall, often hot/high temperatures and low humidity this region presents some challenges to outdoor growers. Cool evenings in spring/fall can make for wide temperature fluctuations. Growers will need to consider their plant water requirements and provide water during drought conditions.

Those growing on their own land in containers may want to move their plants under shade during the hottest part of the afternoon.

Bonus tips:

Growers face several potential problems. Protecting their plants from the fierce midday/afternoon heat being one of the most pressing. Those growing in greenhouses may consider shade-netting/blinds, powerful air-extraction, white greenhouse paint and even greenhouse air-con.

One option for those growing in containers is to deliberately use over-sized containers to offer some heat buffer protection-zone for the cannabis roots. This will also offer some protection from cool nights too. Avoid black/dark-colored containers which can heat up dramatically in full sun, damaging the root zone.

Protection from the overnight low temperatures is another consideration, some greenhouse growers use greenhouse heaters especially for the late-blooming sativa/Haze cannabis seed varieties. Drip irrigation is a popular technique to prevent plants dehydrating/wilting under the punishing combo of heat with low humidity.

California (similar to Mediterranean climate)

On the west coast California offers a great Mediterranean-style climate for outdoor cannabis cultivation. Temperatures can get hot. Ocean regions benefit from the prevailing pacific breeze, helping to prevent temperatures reaching the extreme levels seen further inland.

In San Francisco, daily light hours dip below 14 (hours of light per day) in early August.

Climate specs and key takeaways for cannabis growers:

Large parts of California enjoy great cannabis cultivation weather. Temperatures are warm/hot and sunny. This is suitable for nearly all varieties whether growing outdoors or in a greenhouse/polytunnel. ‘Dedicated’ indoor weed seed varieties can be grown outdoors in California with good results thanks to the long grow season.

But there are notable differences between the cooler northern Cali climate and the hotter south. In the south almost year-round growing is possible and autoflower seed varieties do especially well.

Bonus tips:

Heat protection and regular watering during summer is important. If your plants are not rooted directly into the ground and you are growing in containers then, as previously mentioned, use of large/oversized (or insulated) containers offer some protection against sun. Highly aerated grow containers such as felt sacks, etc are particularly recommended.

Marine West coast (similar to Normandy/UK, depending on latitude)

North of Cali, in Western Oregon & West Washington State lies the Marine West Coast. With cooler and less sunny conditions than California, growers face conditions that are more similar to some of those seen by French (Normandy) and UK growers. Conditions are generally good for cannabis cultivation but not all strains will thrive at these slightly more northern latitudes.

In Portland, Oregon, the days dip below 14 hours of daylight in mid-August.

Climate specs and key takeaways for cannabis growers:

Conditions on the Marine West Coast have similarities with parts of west/north Europe, including Galicia (north Spain) Southern UK and West France. The northern part of this zone has conditions similar to Germany, UK and Benelux (Belgium, Netherlands, Luxembourg).

This means average temperatures with some summer heat. But rain is more of a feature throughout the grow season. Local growers will note that fall can arrive early especially in Washington state.

For those growers at higher altitude, Pamir Gold and Snow Bud are perfect mountain choices. In general, sturdy & resilient outdoor strains are better suited to the Marine West Coast grow region.

Autoflower seed varieties are also a great choice for those concerned about the early arrival of fall weather - which can be risky for slower-blooming photoperiod feminized seed varieties.

Bonus tips:

Be prepared to consider a storm shelter during late flowering. An overhead tarpaulin can be helpful to maximize chances during heavy rainstorms. Growing cannabis plants in containers affords the grower the opportunity to move/protect the plants in the event of damaging weather.

Always use containers with holes in the base, so excess moisture can drain away easily. Many outdoor growers like to lighten their soil mix with the inclusion of e.g. coco fiber. This improves aeration.  For this reason, aerated grow containers (felt sacks, airpots, etc.) are always a solid choice for either indoor or outdoor growers.

When growing several cannabis plants together ensure sufficient distance between the plants so there is better airflow, less chance on fungus/bud rot etc. This also allows easier access for maintenance e.g. removing dead leaves which can otherwise contribute to bud-rot/fungus, especially in a wet/colder environment.

Growing cannabis outdoors in the USA - key takeaways

No matter where you live in the USA you can grow great quality outdoor cannabis. Not all regions suit all strains. So, research your cannabis seed genetics carefully, and favor the seed suppliers that have the experience to offer detailed grow information for their outdoor recommendations.

Preparing and improving your outdoor grow location always pays dividends. If growing directly in the earth, dig it over well, add manure at the end of the previous season and fertilize with minerals/nutrients.

Remember the advantages of germinating your marijuana seeds indoors and giving them the benefit of a few weeks of indoor growth under LED before planting them outdoors.

The two most popular germination methods are to germinate the seed directly in the moist grow medium. Or try the cotton pad germination method - sprout the seeds between two damp (never soaked) cotton pads for the highest germination rates.

The shortening of daylight hours to around 14 - 14.5 (hours of light per day) often denotes the onset of bloom with feminized seed varieties. Understand when this occurs in your grow location. Remember that fast feminized strains such as Think Fast & GMO Fast should bloom a month earlier and be ready for harvest a month earlier than traditional feminized strains. And autoflower seeds with a rapid 3-4 month grow cycle can be grown in all US locations.

Pay particular attention to your local climate and micro-climate. Note the dates of the last spring frost and the realistic arrival point of fall weather.  Autoflower seed varieties are also a great choice for those concerned about the early arrival of fall weather - which can be risky for slower-blooming photoperiod feminized seed varieties.

Less experienced outdoor growers are especially encouraged to try proven/recommended strains rather than be over-adventurous with exotic indoor genetics in a challenging outdoor environment. Here are a few tips to harvest, dry and cure your buds.

Good luck and enjoy your grow!