Growing Cannabis Outdoors: A Starting Guide to Marijuana Cultivation in Nature

Thailand’s tropical climate offers a unique setting for those looking to grow cannabis outdoors. Its abundance of sunlight and specific weather patterns might make it seem like a paradise for growers, but there are challenges that need addressing.

In this guide, we look into the specifics of outdoor marijuana cultivation in Thailand. We start by emphasising the importance of selecting the perfect location and choosing the right seeds and strains. We also explore other crucial factors, such as the nuances of Thai soil and climate and common cultivation challenges, all to help you produce a bountiful yield.

This article serves as a starting point for outdoor cannabis growers. Armed with this knowledge, beginners and experienced farmers alike can master the art of growing a thriving cannabis garden in Thailand’s unique conditions.

What you need to consider

Knowing how to grow marijuana is much more than tossing some seeds in the dirt and waiting. Sure, it might work, but you won’t get the quality of bud that you want.

For example, outdoor cannabis plants can reach up to 5 metres in height, meaning they need a lot of space and support. Secondly, cannabis is a photoperiod plant where the amount of daylight dictates its growth phases. As such, it grows best during the long summer days.

While you can control these parameters indoors with ease, it is difficult to do it outside as you are dependent on nature. As such, you must consider the environmental factors listed below when planning outdoor farming.

Location

Consider the following when choosing your grow site. Meeting most of these criteria will greatly help your plants produce quality flowers.

• Privacy and security: Choose a secluded location to ensure your weed remains out of sight and protected from theft, especially during the final stages of growth.
• Uninterrupted sunlight: Weed needs plenty of sunlight, so choose a sunny location where light can reach the plants for the majority of the day.
• Destructive weather hazards: Weather threats like storms, heat waves, and flooding can spell disaster for your crop. Protect your plants by choosing a sheltered location or preparing for these events with a covering.
• Light pollution: Avoid areas that are exposed to artificial light at night, as it can disturb the plant’s growth cycle. Cannabis needs a 12-hour dark cycle to grow large flowers.
• Sufficient space: Balconies and roofs are all good locations if you’re growing a small number of plants. For larger gardens, use a large space, such as a backyard or a farm.

Climate, wind & rainfall

Growing cannabis outside in Thailand means understanding its varied weather, from changing temperatures and rainfall to wind patterns. Here’s how the weather can affect your cannabis plants.

Temperature and seasons

Thailand has three main seasons, each with its challenges and benefits for cannabis:

• Winter (November – February): The temperature is usually between 15°C to 28°C. This cooler weather is great for starting and growing young cannabis plants.
• Summer (March – June): Temperatures can rise from 25°C to 35°C. Plants need plenty of water during this time as it can get quite hot.
• Monsoon (July – October): It’s still warm, with temperatures of 24°C to 32°C, with heavy rain coming into play. Thailand can get between 1,000mm to 2,500mm of rain during this period, so it’s essential to make sure your plants don’t get too wet.

Different places, different weather

Different parts of Thailand can have slightly different weather. Here’s a highlight:

• Coastal regions (like Phuket and Pattaya): Coastal areas tend to have milder temperatures due to the sea’s moderating influence. They can also experience more consistent rainfall throughout the year, making them relatively humid.
• Northern highlands (such as Chiang Mai and Chiang Rai): These areas, with their higher altitudes, can be cooler, especially during nights in the cool season. The North can also experience fog and cooler temperatures that might not be as suitable for some cannabis strains without adequate protection.
• Northeastern plateau (Isaan region including Udon Thani): This area can be drier and hotter compared to other regions. The temperature fluctuations between day and night can be more pronounced here.
• Central plains (like Bangkok): This region, which includes the capital city, experiences a tropical wet and dry climate. It’s hot and humid for most of the year, with a clear distinction between the rainy and dry seasons.

When deciding where to grow cannabis in Thailand, it’s crucial to consider these regional climate differences and the humidity that comes with it. Growing outdoors in Thailand can be challenging due to high humidity, and as such, it can prevent you from producing high-quality yields.

That’s why choosing a strain that suits the specific climatic conditions of your region – alongside the right prep work – can enhance the chances of a successful harvest.

Growing calendar: When to plant and harvest

If you are planning to grow marijuana outdoors in the Thai climate, the calendar schedule mentioned below is optimal.

Late October to early November

Germinate seeds indoors

Begin your cannabis cultivation indoors during this period. This will allow the seedlings to grow in a protected environment, shielding them from any lingering monsoons or unexpected temperature fluctuations.

Mid-December to early January

Move seedlings outdoors

Once your seedlings have matured and the weather is cooler, it’s time to move them outdoors. The milder temperatures of this period promote steady growth.

February to April

Vegetative phase; prune and train plants

The hot season provides ample light for the vegetative growth of cannabis. It’s crucial during this phase to prune and train your plants, maximising light exposure and airflow. As the heat intensifies, ensure consistent watering without over-saturating the soil. Use shade cloths or nets as necessary to protect your plants from the intense sun, and consider implementing windbreaks or screens to guard against strong winds.

May to July

Flowering phase

The transition from hot to rainy season naturally induces flowering in cannabis plants. Monitor them closely during this time. The earlier rains can be beneficial for the flowering phase, but too much rain can lead to problems. It’s also crucial to ensure your plants are shielded from excessive moisture to prevent mould and bud rot.

Late July to early August

Harvest season

Aim to harvest your cannabis plants during this period before the heaviest of the monsoons arrive. This ensures the buds remain dry and free from mould.

Light

Sunlight is a crucial element for cannabis growth, acting as the energy source for photosynthesis, the process that allows plants to grow and develop. Timing your crop to specific months ensures good sunlight.

• In the germination stage (November-December), Thailand experiences shorter daylight hours, which suits the seedlings’ needs.
• During the vegetative stage (January-February), cannabis plants need lots of light, ideally 18-24 hours a day. The longer daylight hours of the Thai winter align well with this requirement.
• In the flowering stage (March-April), the plants need 12 hours of light and 12 hours of darkness daily. This encourages bud production. As we move towards spring, Thailand experiences gradually decreasing daylight hours, which fits well with this requirement.
• Finally, during the harvesting period (May-June), the amount of sunlight is not critical. The plants are maturing and getting ready to be harvested. The daylight hours in Thailand continue to decrease during this period, which doesn’t negatively affect the mature plants.

Pest control

A wide variety of pests thrive in the warm and humid climate of Thailand. This means your outdoor marijuana plants are at risk of infestation from bugs and insects. Being proactive and understanding the local pests can help in effectively managing and preventing infestation.

Common pests that can bother your plants are red spider mites, grasshoppers, whiteflies, caterpillars, and aphids. Wild animals can also come and feast on your plants if physical barriers and protection are not intact.

How to prevent pests from damaging your cannabis garden?

Implementing a combination of preventive measures and timely treatments can be your best defence against the various pests that thrive in Thailand’s warm and humid climate.

You can take preventive measures like:

• Neem oil: A natural insect repellent, neem oil can deter a wide range of pests. Regularly spraying a diluted solution can act as a preventive measure.
• Companion planting: Grow other plants like marigolds, basil, or chrysanthemum alongside cannabis. These plants act as natural repellents for certain pests.
• Beneficial insects: Introducing natural predators like ladybugs and lacewings can help control pests like aphids and mites.
• Regular inspection: Routinely inspect the plants for signs of pests or damage. Early detection can help in effective control and prevention.
• Physical barriers: Use netting or mesh to protect your plants from larger pests like grasshoppers and moths.

Try the following treatment measures if your plants do catch an infestation:

• Insecticidal soaps: These are safe for plants and effective in dealing with pests like mites and aphids.
• Diatomaceous earth: This is a natural insect killer and can be sprinkled around the base of the plants to deter crawling insects.
• Organic pesticides: There are several organic pesticides available that are safe for cannabis plants and effective against a range of pests.
• Manual removal: For larger pests like caterpillars, manual removal might be the most effective method.

Strain selection

Choosing the ideal cannabis strains for outdoor cultivation requires careful consideration of genetics, growth characteristics, and local conditions.

Hybrids, Sativas, and Indicas

You will find three cannabis varieties of cannabis flowers – Sativa, Indica, and hybrid. Each has unique traits like smell, height, taste, yield, and resiliency to the surroundings. Knowing what you seek from the plants will help you determine which variety to grow.

• Sativas: These strains flourish in Thailand’s hot and humid conditions, particularly during its warm seasons.
• Indicas: While traditionally favouring cooler climates, certain indica strains can adapt to Thailand’s cooler months, especially in the northern regions.
• Hybrids: Combining the traits of both sativas and indicas, hybrids can offer the best of both worlds, adapting to varying temperatures throughout the year.

Autoflowering

Autoflowering strains are resilient and don’t rely on light cycles, making them suitable for unpredictable weather. These feature the genetics of cannabis Ruderalis – which makes them highly resilient and excellent for outdoor growth.

You don’t have to worry about lighting at all since they move to different stages based on age.

Landraces

Landrace strains are adapted to specific regions, offering unique growth experiences tied to their heritage. There are Thai landraces which are naturally adapted to the country’s climate. They have evolved over time in sync with the local environment, making them a top choice for outdoor cultivation.

Aroma

While the scent of a cannabis plant might seem secondary, it’s an important consideration for growers. Intensely fragrant strains can draw attention, whereas strains with a more discreet smell ensure a level of privacy.

Resistance to pests & diseases

Some strains are naturally more resistant to pests and diseases common in the area. Given the tropical weather of Thailand, your plants will encounter a lot of bugs. To maximise your chances of a bountiful harvest, look for strains that are genetically resistant to things like moulds and pests.

Recommended strains for outdoor growth in Thailand:

• Thai Landrace: Tailored to the local climate.
• Durban Poison: A resilient Sativa for warm, humid conditions.
• Northern Lights: A world-famous Indica which can handle cooler temperatures, making them suited for the Northern regions.
• Auto Blueberry: The autoflowering versatility of the Blueberry strain gives them the edge to handle the Thai weather well.
• Lowryder: A discreet, compact autoflower option.

Make the most of your outdoor cultivation by matching strains to your environment and preferences.

Watering

Watering your cannabis plants depends on various factors, like the stage of growth, type of soil, and weather conditions. A rule of thumb: water your plants once the top inch of soil has dried out completely to avoid the risk of root rot.

Here’s a handy watering guide for different phases:

Young seedlings

Freshly sprouted cannabis plants are delicate. In Thailand’s tropical climate, it’s tempting to overwater, but do not do that. Lightly moisten the soil, ensuring it doesn’t become waterlogged, especially during the rainy season. That is why it is an idea to good idea to grow these saplings indoors before taking them outside.

Vegetative phase

As your plants grow, they’ll drink up more, especially during Thailand’s scorching hot season. Check the top layer of soil; if it feels dry in the morning, give them a good drink. Sometimes, a second watering might be needed in the late afternoon.

Flowering phase

Come flowering time, Thailand’s high humidity is a challenge. Your plants need water, but too much can lead to bud rot, a common issue in humid regions. Monitor the soil’s moisture, ensuring it’s damp but not soaking, especially during the rainy season.

Choosing the right water for your marijuana plants

When it comes to growing marijuana, the water you use plays a pivotal role in the health and productivity of your plants. Here’s a breakdown of the water types:

Tap water:

• Begin by checking the pH to ensure it’s between 6.0 – 7.0. Although tap water is readily available, it may contain chlorine and other contaminants, making it a bad choice for plants.

Bottled water:

• A dependable choice with consistent quality, bottled water often surpasses tap water in terms of purity and reliability.

RO (Reverse Osmosis) water:

• Renowned for its near-purity, RO water stands out as the top choice for cannabis cultivation. However, the initial investment can seem a bit high.

For those seeking the utmost precision in their cultivation process, RO water offers unparalleled control. Yet, for growers looking for a straightforward, hassle-free approach, bottled spring water emerges as a trusty alternative.

Pests

Is it legal to grow marijuana outdoors in Thailand?

According to the Ministry of Public Health in Thailand, it is legal to grow weed for personal purposes. Thai citizens can grow no more than 15 plants at home as long as they register with the government first. Keeping the local police in the loop is also good in case of surprise inspections.

Seeds or clones: Taking the first steps

Embarking on your cannabis cultivation journey involves a crucial choice: whether to begin with seeds or just buy clones. Here’s what you need to know.

Feature	Buying Clones	Growing from Seeds
Genetic Consistency	High (Exact genetic replica of the mother plant)	Variability possible due to genetic factors.
Initial Growth Speed	Faster (Skips germination phase)	Slower (Requires germination and seedling phase).
Strain Variety	Limited (Based on available mother plants)	Broad (Many seed options available).
Vulnerability to Pests/Diseases	Risky (Any disease in the mother plant can affect clones)	Lower (Starting fresh can offer a disease-free start).
Time to Harvest	Generally quicker (due to skipping early stages)	Longer (Must navigate through all growth stages).
Initial Investment	Can be more expensive (Purchase of established plants)	Typically cheaper (Seeds generally cost less than clones).
Experience Level	Novice to Expert (Easier for beginners)	Mostly for intermediates to experts (Requires careful nurturing)
Transplant Shock	Lower (Clones are often ready for transplanting)	Can be higher (Transferring seedlings can be delicate).

Growing your seeds

You can grow your seeds either indoors or outdoors. The decision comes down to your level of experience, the resources you have at hand, and your comfort level with potential risks.

Indoors

For many growers in Thailand, planting seeds and even growing their cannabis indoors is a preferred choice.

The controlled environment shelters young plants from sudden downpours or an unexpected heatwave. You can also closely monitor moisture levels and light, ensuring that seedlings have the best start. (This level of control, when monitored all the way to the flowering phase, ensures buds of the highest quality.)

Once these young plants have grown stronger, usually a few weeks in, they can be carefully transitioned outdoors, matching Thailand’s best growing periods.

Outdoors

Some seasoned growers opt for direct outdoor planting. They believe that this method aligns the plant’s growth cycle with the rhythms of nature from the get-go. By doing this, plants might develop a natural resilience to local weather conditions. However, this approach has its risks. Young seedlings can be vulnerable to heavy rains or external influences like pests, wildlife, or harsh weather.

Buying clones: a faster start

Clones, cuttings from a ‘mother plant’, offer growers a predictable and consistent cannabis journey. Unlike seeds, which can introduce genetic variability, clones retain the exact genetics of their parent. This ensures that their growth patterns and characteristics remain constant, making them especially valuable in Thailand’s diverse climatic conditions.

A significant advantage of using clones is the time saved. Skipping the germination phase, clones, when transplanted, can swiftly progress in their growth cycle. This means a quicker harvest, aligned efficiently with Thailand’s varying weather patterns.

In conclusion, the choice between seeds and clones hinges on your expertise, available resources, and aspirations. Consider both approaches’ advantages and decide which aligns best with your vision for a thriving cannabis garden.

The importance of soil

Good soil is the foundation for a thriving cannabis plant. Whether you’re working with native soils or introducing a custom mix, understanding the composition and properties of the soil can significantly impact your cultivation success.

Types of soil

Here are the kinds of soil that may be in your backyard:

• Loam soil: A blend of sand, silt, and clay. It’s excellent for gardening due to its moisture and nutrient retention, but it might be pricier and less accessible.
• Sandy soil: Light and drains quickly, preventing overwatering, but struggles with long-term nutrient retention.
• Clay soil: Nutrient-rich but can retain excessive water and become compacted. Common in Thailand’s rice-growing regions.
• Silt soil: Fertile and moisture-retentive but can compact easily, making root spread challenging.
• Peat soil: High in organic material and moisture retention. However, its low pH might require adjustments.
• Commercial Potting Mix: Ready-to-use mixes with balanced nutrients and good water retention.

Throughout Thailand, you are likely to find a combination of clay, sandy, and silty soils. The clay soil, known for its high nutrient content, is common in rice-growing regions. Sandy soil tends to be in coastal areas and along river banks, given its quick-draining function. 

Why organic soil can make a huge difference?

Organic soils, filled with beneficial microorganisms and rich in nutrients, can offer the best environment for cannabis growth. They promote healthy roots and improve the plant’s resistance to diseases.

For growers preferring a hands-on approach, creating a custom soil blend allows for precise control over its composition, factoring in the specific needs of the strain you’re growing. This might involve mixing organic materials such as compost, worm castings, or bone meal to enhance soil fertility and structure.

The main difference between organic soils and what you find at the local shop is that organic products are filled with naturally occurring microorganisms and nutrients, whereas commercial soils are often artificially enriched and may contain chemical ingredients.

The importance of soil pH

The pH of the soil directly affects the health and yield of your cannabis plants. pH levels measure the between acidity and alkalinity in the soil, which tells how efficiently the plants can absorb nutrients.

When soil pH is balanced, plants can easily absorb essential nutrients from the soil. However, when the pH is too high (alkaline) or too low (acidic), certain nutrients become less available, leading to potential deficiencies and affecting plant growth.

In Thailand, the average soil pH hovers around 6.5-7.5, making it slightly acidic to neutral. This range is generally favourable for most plants, including cannabis. If the soil’s pH drifts outside this range, it can trigger nutrient lockout, causing the plant to struggle to absorb the necessary nutrients.

Testing and adjusting soil pH

• Testing pH: For precise readings, use a pH meter inserted directly into the soil. Alternatively, pH strips offer a budget-friendly option. By mixing a small soil sample with water and dipping the strip, you can get a rough estimate of the soil’s pH.
• Adjusting pH: Depending on the test results, you might need to adjust your soil’s pH. Lime can be added to raise pH (make it more alkaline), while sulfur or other pH-down products can lower pH (make it more acidic).

Regular pH monitoring is essential, especially in regions with varying rainfall patterns or after using a fertiliser. Keeping an eye on pH ensures healthier growth and better yields.

Growing containers

When cultivating cannabis outdoors, choosing the appropriate growing containers significantly influences plant health and growth. For example, pots offer portability and controlled growth conditions. Planting directly in the soil provides more space for root expansion but limits mobility.

Moreover, container size is vital. Too small, and roots become cramped; too large, and excess soil retains water, leading to root rot. Strike a balance based on your plant’s expected size and growth phase.

Types of containers

• Plastic pots: Are affordable and available in various sizes, but they can heat up in sunlight.
• Fabric pots (grow bags): Enhance drainage, prevent over-watering, and promote air pruning. They may require more frequent watering.
• Ceramic pots: Sturdy, keep plants cool, but they’re heavy and less portable.
• Air pots: Designed with holes, they enhance oxygenation, promoting a healthier root structure by preventing root circling and facilitating air pruning.
• Raised beds: Great for ample space, they offer good drainage, but require more soil and are immobile.
• Hanging baskets: Suitable for limited space, deter pests, but require frequent watering and restrict root growth.

Ultimately, the choice depends on your space, mobility needs, and plant size. Consider the pros and cons of each container type to create an optimal environment for your outdoor cannabis cultivation.

Nutrient requirements

At a basic level, plants require macronutrients and micronutrients. The primary macronutrients are Nitrogen (N), Phosphorus (P), and Potassium (K), commonly referred to as the N-P-K ratio on fertilizers.

In addition to N-P-K, plants need secondary macronutrients like Calcium (Ca), Magnesium (Mg), and Sulfur (S).

Micronutrients, needed in smaller quantities, include elements like Iron (Fe), Manganese (Mn), and Zinc (Zn).

Ready-made nutrient solutions

Growing cannabis outdoors comes with its challenges, and feeding your plants right is key. Ready-made nutrient solutions, made just for cannabis, are a handy choice. They give plants what they need without the guesswork. These mixes are great for outdoor growth because they tackle the ups and downs of nature.

That said, always stick to the bottle’s directions to avoid giving plants too much.

Making your own nutrient-mix

A more hands-on and eco-friendly method involves using compost. This organic matter, derived from decayed plants and kitchen scraps, not only provides nutrients but also improves soil structure, water retention, and microbial activity.

For example, coffee grounds are a quick-decomposing source of nitrogen, ideal for leaf and stem growth. When your plants move to the flowering stage, bone meal provides the necessary phosphorus for roots and blossoms. For general health and disease resistance, bury banana peels to release potassium. Other such items that can help you maintain a healthy nutrient mixture in soil are Epsom salt, seaweed extracts, and eggshells.

For outdoor growth, adding well-aged compost can be a game-changer, creating a rich environment for roots to flourish.

Nutrient for different growth phases

• Seedling phase: During the early stage, focus on a nutrient mix with higher levels of nitrogen to support healthy leaf development.
• Vegetative phase: Switch to a balanced nutrient mix with equal proportions of nitrogen, phosphorus, and potassium to encourage vigorous growth.
• Flowering phase: Shift towards a nutrient mix with higher phosphorus and potassium levels to promote robust flower development.

Regular monitoring of your plants’ health, soil pH, and nutrient levels is key. Adjust nutrient application based on visual cues and, if needed, conduct soil tests to ensure optimal nutrient levels throughout the growing cycle.

How to maintain cannabis plants outdoors?

As your cannabis plants thrive outdoors, it’s essential to provide them with the right care throughout their growth journey. Consider the following to ensure a healthy harvest. These are above and beyond the essentials that we have discussed above.

Pruning

Trim away unnecessary leaves and branches to help the plant grow better and let more light reach inside. This results in increased energy to productive areas and healthier plant growth.

Training

Use techniques like Low-Stress Technique (LST) or High-Stress Technique (HST) to shape your plant. This helps them get more light and can lead to bigger yields. Shaping controls growth and maximizes the plant’s energy.

Staking/Support

As plants get taller and buds heavier, give them some support with stakes or cages to prevent breaking. Proper support ensures they grow upright, protecting your investment.

Soil aeration

Gently loosen the soil around your plant. This helps roots breathe better, making the plant healthier. Well-aerated soil ensures robust root development.

Companion planting

Plant certain plants near your cannabis. They can keep pests away, help the soil, or even hide your cannabis. This symbiotic relationship benefits both plants.

Mulching

Put organic stuff like straw on top of the soil. It keeps moisture in, stops weeds, and keeps the soil temperature just right. Mulching also adds organic matter back to the soil over time.

Conclusion

Growing cannabis in Thailand revolves around three main ideas: finding the best spot considering the local weather and land, selecting seeds that suit the tropical conditions, and understanding the unique nature of Thai soil. In addition, general things like watering schedule, nutrients, and protecting your plants from external factors add to your chances of a good yield.

Initially, it may be difficult for you to get these things right – but with time and experience, you will become only better. You can further explore these insights by browsing our growing cannabis section.