Force-Flowering Cannabis Outdoors: Yes, You Can Do It!
Growing cannabis outdoors can be tricky because you must rely on the natural light cycle to support your plants’ growth. But the location of your garden or the local climate might not always allow your plants to go through their entire flowering cycle as intended. That’s where force-flowering can help you achieve a perfect harvest! Here’s how.
Learn how to force-flower your outdoor weed plants.
Outdoors, under the sun is arguably one of the best ways to grow your own weed. Unfortunately, growing outdoors can be tricky if you live far north or south or along the equator. Luckily, you can overcome some of the challenges of growing in these areas by force-flowering your outdoor plants. In this article, we’ll walk you through the process, so you can gain more control over your outdoor grow.
When Does Cannabis Flower Outdoors?
Photoperiod cannabis plants start to flower at the end of summer (following the summer solstice), once the days get shorter and the nights grow longer. Latitude obviously has a big impact on when weed flowers, as it correlates to the number of daylight hours in a particular region.
In general, however, cannabis plants will start flowering after the June solstice (June 20th or 21st, depending on the year) in the Northern Hemisphere and after the December solstice (December 20th or 21st) in the Southern Hemisphere. Keep in mind that the switch to bloom is a lot more gradual outdoors, as daylight hours decrease by a matter of minutes every day.
How Long Does the Flowering Stage Last?
How long a plant takes to flower outdoors varies depending on its genetics and its environment. In general, however, cannabis plants can be harvest-ready between September and November in the Northern Hemisphere and March–May in the Southern Hemisphere.
Why Would You Want to Force-Flower Cannabis?
When we think of outdoor growing, we tend to believe we have almost no control over the light cycle of our cannabis. But that doesn’t have to be the case. While there’s a certain beauty to letting nature run its course, sometimes a bit of human intervention can make the difference between an average harvest and a great one.
Benefits of Force-Flowering Outdoor Cannabis Plants
Here’s why you might want to consider forcing your outdoor plants to flower:
Areas far north or south of the equator tend to have long, harsh winters that set in a lot earlier than in other areas of the globe. If you’re growing outdoors in northern Europe or southern Argentina, for example, you may want to force your plants to flower a little early to avoid early winter frosts or rain destroying your harvest.
If you live along the equator, on the other hand, you may want to force-flower your outdoor plants to keep them from growing too large. Due to the long, consistent hours of sunlight these areas get all throughout the year, photoperiod strains growing close to the equator can take a long time to start flowering and, given enough space, can grow massive.
You don’t need to be living in Tierra del Fuego or Oslo to be intrigued by the idea of force-flowering your outdoor plants. In fact, a lot of outdoor growers opt to force their plants into bloom to produce multiple harvests throughout the year. Some experienced growers even produce perpetual harvests approximately every two weeks throughout the growing season.
When Can You Force-Flower Cannabis Outdoors?
If you live in a cool, temperate climate zone (like the UK, northern Europe, or far south in South America), you may face cold, damp autumns and early winters that overlap with the end of your plants’ bloom phase. To stop these conditions from jeopardising the quality and size of your harvest, we recommend forcing your outdoor plants to flower prematurely during mid-June or early July in the Northern Hemisphere and mid-January or early February in the Southern Hemisphere.
In the UK, for example, outdoor cannabis plants naturally won’t start flowering until September (approximately). In order to avoid the harsh rains and winds of autumn, we recommend outdoor growers in the UK force their plants into bloom as early as mid-June or early July. Given the cold spring in the region, you’ll likely also want to start your plants off indoors.
If you live close to the equator or in the tropics, on the other hand, you may be able to grow outdoors all year round. Given these conditions, you can essentially force your plants to flower whenever you like (local weather permitting, of course).
How to Force Cannabis Flowering Outdoors
The principle behind force-flowering outdoor plants is simple; just reduce the amount of light your plants get. How you choose to do this, however, depends on the number of plants you’re growing and the weather in your area.
If you’re growing a handful of plants on a balcony or terrace and don’t have extreme temperatures and harsh rains to worry about, a simple wooden or PVC frame fitted with a light-proof tarp might be all you need; simply pop your plants under the tarp at night and give them a full 12 hours of uninterrupted darkness to force them into bloom.
Alternatively, you could also move your plants into a garage, cellar, or shed at night; just remember that the area needs to be 100% light-proof for the plants to start flowering properly.
If you’re growing a lot of plants, you probably don’t want to lug them around every day. In this case, you may want to consider an automated tarp or roof above them. You can then use a timer to ensure your plants go undercover at the same time every day, without having to move them inside individually.
If the weather in your area isn’t so favourable during early autumn, you may want to invest in a small indoor grow tent complete with a light and fan. Once you’re happy with how your plants have vegged outdoors, bring them into the tent to finish them off without having to worry about the cold, rain, or wind.
Force-Flowering: Factors to Consider When Covering Your Plants
While force-flowering is pretty simple, there are a couple of things you’ll want to keep in mind to make sure the process goes down smoothly.
When you move your plants undercover, one of the first things you’ll want to think about is air circulation. Stale, stagnant air can drive up the temperature and relative humidity around your plants, creating a breeding ground for pests, fungi, and bacterial pathogens. Whether you’re keeping them under a DIY frame with a tarp or in an indoor grow tent, make sure you have clean, fresh air circulating around the space to keep your plants healthy.
Next, you’ll want to stick to a tight schedule. Photoperiod strains are very sensitive to light cycle changes, and a small slip-up when you’re trying to force them to flower can revert them back to veg or trigger hermaphroditism. For the best results, create a consistent flowering schedule with plenty of reminders to ensure your plants go under and come out of cover at the same times every day.
Finally, you’ll want to make sure that the structure housing your plants during their bloom phase is 100% light-proof. Light leaks during the flowering cycle can cause your plants a lot of stress and interrupt their flowering cycle. Wherever you’re keeping your plants, make sure there is absolutely no light exposure during the dark hours.
Don’t Want to Force-Flower? Try Fast-Flowering or Auto Strains
Rather than having to force-flower your outdoor plants every season, we recommend looking into strains with flowering times suited to your local climate.
Our fast-flowering strains, for example, are specially bred to flower in as little as 40 days. Our experienced breeders have developed these strains especially for growers looking to get to harvest sooner or pump out multiple harvests per season.
Alternatively, autoflowering strains are another great option, especially if you live in the tropics or close to the equator. Unlike feminized or regular strains, our autoflowering cannabis varieties are specially bred with ruderalis genetics and flower automatically based on their age, rather than changes in their light cycle. If you’re looking to pump out multiple harvests per year, our autos are the way to go.
Below are some of our favourite fast-flowering and autoflowering strains:
Candy Kush Express
A cross between Sweet Special and Royal Kush, Candy Kush Express is a well-balanced hybrid with great potency and delicious sweet citrus aromas. A direct descendant of an Afghan Kush, Candy Kush Express boasts a big, heavy stone that’ll leave you glued to the couch for hours. Finally, with a flowering time of only 7–9 weeks, few photo-feminized strains are this quick to reach harvest.
Wondering if it's possible to force outdoor weed plants into flower? Well, it is! Click here to learn everything about force-flowering outdoor cannabis plants.
An intro to outdoor cannabis cultivation
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- How to grow marijuana outdoors
- Choosing the best site for outdoor cannabis growth
- Planning your garden
- Greenhouse basics
- How to grow bigger buds outdoors: tips for success
Outdoor cultivators utilize the best mother nature has to offer in hopes of producing the best possible harvest. Many cannabis users agree that the best marijuana they’ve ever experienced has been grown outdoors under the full spectrum of natural sunlight. That unique spectrum creates a greater variance of cannabinoids and terpenes than artificial lighting, while indoor grows are often aimed at producing higher levels of THC, in particular.
Cannabis has been cultivated outdoors for thousands of years, but before you go putting a seedling into the soil, it’s best to know how the process works and under what conditions outdoor growth is most successful.
Growing outdoors is a great option for those new to cannabis cultivation and wanting to learn how to plant marijuana or people seeking a more natural environment for their plants. Outdoor gardens are cost-effective, do not need expensive environmental controls, and require few resources to get started.
When growing outdoors, the sun’s full spectrum of light makes a world of difference. Each part of the light spectrum contributes to the growth and development of the molecules that make up the resulting plant, including terpenes and cannabinoids. Plus, without the constraints of ceiling height and indoor square footage, plants can really spread their wings, so to speak. Outdoor growers often choose this cultivation method in order to maximize natural light exposure and their yearly harvest.
However, outdoors cultivators must also battle the natural elements, which can potentially diminish the overall yield or reduce the quality of the crop. The many factors that outdoor growers must take into consideration include diminishing light on a cloudy or rainy day, the potential to be invaded by a wide variety of pests, and the limitation to one growing season per year.
How to grow marijuana outdoors
To grow cannabis outdoors, the bare minimum required is basic gardening tools, soil, pots, a hose with access to water, and a spot in your backyard that receives ample sunlight.
Using mother nature to cultivate cannabis
Cannabis is a hardy plant that has adapted to climates all over the world. From the cool and arid mountains of Afghanistan to the humid regions of Colombia, the plant has been forced to adapt over time to build its defenses against a host of conditions. But cannabis is still susceptible to extreme weather conditions. Whether it is heavy winds breaking branches or excessive rain causing mold, the great outdoors presents challenges to growers that can be avoided with sufficient planning.
Becoming intimately familiar with your local climate and seasons is one of the most important steps in producing high-quality outdoor marijuana. Before you grow, you’ll need to know the ideal temperature your plant needs in order to thrive, the season’s photoperiod — the amount and intensity of light available through the duration of the growing season, the best site, and the optimal timing of your planting and harvesting.
Some cannabis genetics have adapted to specific climates and are capable of growing more easily in certain conditions than others, so cultivators pay very close attention to the cultivars, more commonly referred to as strains, that they choose. A little research will go a long way in ensuring you have a successful harvest. While cultivars may vary, there are some general rules of thumb that will be useful no matter which cultivar you choose.
Daytime temperatures between 75 and 85 degrees Fahrenheit, or 23.9 to 25.4 degrees Celsius, are ideal for cannabis, while temperatures above 88 degrees Fahrenheit (31.1 degrees Celsius) or below 60 degrees Fahrenheit (15.6 degrees Celsius) can delay growth. Cannabis is considered heat-tolerant, but sustained highs and extreme lows will usually lead to complications that could eventually kill your plants.
In the Northern Hemisphere, cannabis can be planted in early to mid-spring and usually harvested in mid-fall, depending on the cultivar. In the Southern Hemisphere, the growing season will be reversed, planting in early to mid-fall and harvesting in the middle of spring.
During the first half of the season, the daytime period increases until the summer solstice, which occurs in the Northern Hemisphere on or around June 21 and in the Southern Hemisphere on or around December 21. While the daylight hours increase, the plant’s vegetative stage takes place. During vegetation, the plant will develop the roots and stems that will serve as the foundation for growth until flowering.
After the solstice, the available daylight hours decrease, allowing the plant to naturally transition into the flowering period. Cannabis is a short-day plant, meaning it will begin to flower as the nights get longer and the hours of sunlight decrease.
Most cultivars will begin to flower once they receive fewer than 15 hours of sunlight per day. The latitude of your garden has a direct impact on how many hours a day your plants receive light.
It is important to plan your planting schedule to ensure your plants are able to finish their flowering period before the cold, rainy fall weather is able to affect them.
Choosing the best site for outdoor cannabis growth
Choosing the best site for your garden is another important factor that can affect the yield and quality of your plants. Cultivators in the Northern Hemisphere should attempt to place their plants in an area with southern exposure to ensure their plants are getting the most available sunlight by facing the sun’s archway near the equator. The opposite is true for the Southern Hemisphere.
When possible, use natural structures and formations in your garden as windbreaks to prevent excessive stress on your plants that could lead to branches breaking.
If you live in a climate with exceptionally hot and sunny days, shade cloth can be used to prevent your plants from overheating. In cold areas, natural enclosures and cement or brick walls can be used to help retain any available heat to keep your plants warm.
Depending on your location, you may need to plan for rain. In most regions, the rainy season is typically aligned with the end of the flowering stage and the start of the harvesting period, but this may not always be the case. Rain can be detrimental to an outdoor flowering crop and being prepared to cover or move plants can help ensure a successful harvest. If it does rain on your plants, make sure to immediately shake off any excess water, as excessive moisture can lead to the formation of mold, which can ruin your harvest.
Planning your garden
Seeds vs. clones
Deciding whether to start with seeds or clones will change the timing and manner by which your plants are introduced to the outdoors.
Plants grown from seeds are typically heartier and more vigorous than clones, as they produce a sturdier taproot that clones are not able to replicate. The vigor that comes from deep roots can be an advantage when dealing with harsh environmental conditions and pest pressures. The disadvantages of growing seeds is the additional attention required to germinate the seedlings, the necessity to eliminate any males before they pollinate the females, and the high variability in growth characteristics that results from their genes.
Plants grown from seeds are typically heartier and more vigorous than clones, as they produce a sturdier taproot that clones are not able to replicate. Photo by: Gina Coleman/Weedmaps
If you decide to use seeds, make sure you start them about a month before you would typically start clones to give them time to germinate and adequately develop their taproot.
There are also many advantages and disadvantages of using clones. They can be found at your local dispensary, are from a proven genetic lineage, and typically do well outdoors, making them the perfect choice for inexperienced growers. On the other hand, clones develop a fibrous root system, as opposed to the deep taproots that are developed with seeds. Fibrous root systems can reduce their ability to deal with environmental stress and predatory insects.
Whether starting from seeds or clones, many cultivators start growing their plants indoors to ensure the plants are not exposed to excessive weather conditions as they develop their initial root system. The plants are transitioned outdoors when the weather and photoperiods, or the times in which a plant is exposed to light, are ideal. Extending the indoor vegetative growth period can help increase yields and allow growers time to select the best plants to be moved outdoors.
Media and containers
There are many options when it comes to types of soil and how you can plant your cannabis plants outdoors.
Quality soil should be dark, rich in nutrients, and have a light and fluffy texture. The structure of your soil should be capable of retaining water while also allowing for excess drainage. Organic potting soil blends from your local garden center will do just fine, but more advanced growers prefer to blend their own organic soil from scratch. The soil itself should be slightly acidic with a pH of around 6. This can be tested with a soil pH meter or test kit.
Container gardens can be convenient as they can be moved around the garden to maximize sunlight or protect them from harsh conditions Photo by: Gina Coleman/Weedmaps
Container gardens can be convenient as they can be moved around the garden to maximize sunlight or protect them from harsh conditions such as rain, heavy winds, or extreme temperatures.
Avoid clay pots as they can be costly, heavy, and retain heat that could dry out the plant’s soil and roots. Fabric pots are the least expensive and most effective solution, as they allow for ample drainage and plenty of oxygen to get to the roots. Plastic containers are also light and inexpensive, but tend to retain more heat than fabric pots. Flowering plants need a container that is at least 5 gallons, or 18.9 liters, or larger to prevent the plants from outgrowing their containers and becoming rootbound.
Planting directly into the ground or a raised bed requires a bit more preparation, but has its benefits as well. Without a container to restrict growth, roots can grow deep and thick to support a strong plant. The added surface area also allows the plant to access a greater quantity of nutrients and water in the soil, compared with a container garden. The major downside is that the plants cannot be moved and could require additional structures to protect them in the case of extreme weather.
Cannabis requires more nutrients than many of the common plants you may have in your garden. Quality soil contains enough organic nutrients to start the growth cycle, but as your cannabis plant grows and transitions into flowering, it may deplete the available nutrients and require additional fertilizers.
The three primary nutrients that are required for cultivating marijuana are: nitrogen, phosphorus, and potassium.
During the vegetative phase, the plants need more nitrogen in order to create the roots and leaves that serve as the base for flowering. During the start of the flowering cycle, the plants will require more phosphorus and potassium than nitrogen. Towards the end of the flowering cycles, once the majority of the nitrogen has been depleted, the plants will focus their attention on using the remaining nutrients. The lack of nitrogen is largely responsible for the vibrant purple and orange hues that can be seen on large fan leaves and throughout the plants’ colas.
Avoid all-in-one fertilizers as they can be too high in nitrogen for the flowering cycle and damage any beneficial micro-organisms that may be present in the soil. It is suggested to choose a line of nutrients that is created specifically for cannabis, and to use its suggested feeding charts to avoid overfeeding or underfeeding. Organic sources of nutrients are usually preferred, as they are a great source of beneficial microbes, but may take longer to break down and become available to the plant. Both types of nutrients can be found in dry, pre-blended powders or liquid emulsions, but can also be made from scratch with the right ingredients. Organic compost tea, which includes nutrient rich ingredients, like molasses and earthworm casting compost, is a popular brew for outdoor cannabis farmers.
Organic sources of nutrients include alfalfa meal, bone meal, kelp meal, bat guano, fish emulsion, dolomite, and earthworm castings. Each contains different ratios of nutrients that can be used for different phases of the plants’ growth cycle.
Watering and feeding plants
The amount of water a plant needs largely depends on its size, the size of its container, soil type, and general environmental conditions such as the weather and the intensity of the sun. Larger plants and warmer environments tend to use more water than smaller plants and cooler weather. The amount of water will change throughout a plant’s cycle.
During the vegetative stage, your plants should be watered thoroughly, while waiting to water again until the top 1 inch, or 2.54 centimeters, of soil has dried out. This can be every day or every four days, depending on conditions, but the time between waterings will become shorter as the plant grows its roots. Container gardens tend to dry out faster than soil beds, so they’ll need to be watered more frequently.
Wilting plants and dry soil are a direct sign that the plants need water. Droopy leaves along with wet soil are a sign of overwatering. Both are common mistakes and can be corrected with some practice.
For a small garden, hand-watering is the easiest, cheapest way to water plants. It also allows you to get familiar with each cultivar’s needs and gives each plant the exact amount of water it needs. Irrigation systems can be convenient for a large number of plants or for times when you cannot be in your garden.
Pest and weed control
Pests and wild plants are an inevitable occurrence when cultivating outdoors. Most issues can be avoided with proper planning. Clearing a buffer area around you plants can go a long way, but your first line of defense is a healthy plant that can defend itself naturally.
Pests come in many forms, from large deer and gophers to small slugs and spider mites. Larger animals and pets can be kept out of the garden with fencing, while gopher wire beneath your soil beds can keep rats and gophers from eating the plants’ roots. Weeds will not damage cannabis, but they will compete for the nutrients in the soil and reduce the quality and yield of your crops. A light layer of mulch on top of your soil can prevent additional weeds from sprouting in the middle of your cycle.
Avoid spraying synthetic insecticides on your cannabis plants as further research is needed to determine the health effects of smoking plants treated with synthetic chemicals. Organic pesticide and insecticide solutions can be effective if used properly. If you can avoid it, it is always best to not spray anything on your plants while they are flowering.
Beneficial insects, fungi, and bacteria can also be used to protect your plants from their parasitic or predatory counterparts. Jumping spiders, ladybugs, and other native, beneficial predatory insects can clear your crop of insects such as aphids and whiteflies. When sourcing beneficial insects, fungi, or bacteria, it’s important to research those which are native to your region.
Even if it is legal to grow your cannabis outdoors, you should still take some precautions to hide the plants from public view. You can grow your cannabis plants among other common plants in your garden and try to hide them in plain sight. Cannabis can easily grow taller than your average fence, though. Training techniques can help keep your plants shorter. The fewer people who know you are growing cannabis, the better, the ideal situation is to have your grow on a piece of tucked away land so plants can truly flourish.
Greenhouses can be a great middle ground between the complexities of an indoor setup and the uncertainty of growing outdoors. They provide ample protection from the elements and use far fewer resources than an indoor grow. Greenhouses can be more costly than an outdoor garden and require more planning, but they also allow you to extend the growing season considerably.
Greenhouses also offer growers the ability to harvest more than one cycle per year if they are equipped with a light deprivation system. These systems allow growers to control the hours of sunlight their plants receive, much like turning lights on and off in an indoor garden, by covering the greenhouse with a black tarp that deprives the plants of sunlight.
Greenhouse structures range from inexpensive polyvinyl chloride (PVC) tubes, often called “hoop houses,” to highly engineered, fully automated, and purpose-built steel greenhouses. Due to their efficiency, greenhouses are quickly becoming the preferred growing method for many large-scale cultivators.
How to grow bigger buds outdoors: tips for success
Here are a few marijuana growing tips to get the most out of your growing experience:
The smallest adjustments can make all the difference — planting a week earlier, a week later, watering less, watering more, etc.
Quality soil is crucial to the success of your crop and one of the few factors that you have control of when outdoors.
Timing is key. A short vegetative phase can cause cannabis plants to flower early, while a long vegetative phase can prevent your plants from finishing their flowering cycle if the weather takes a turn for the worse. The Farmer’s Almanac is a reliable source for planning around the seasons and preparing your crop for success.
Practice makes perfect, so always keep a grow journal and make sure to record any mistakes and wins along the way. Maintaining a record can help ensure you will have successful future harvests.
An intro to outdoor cannabis cultivation Copy article link to clipboard. Link copied to clipboard. Contents How to grow marijuana outdoors Choosing the best site for outdoor