How to grow marijuana outdoors

Growing marijuana outdoors is great because you won’t need to spend a ton of money on it and you can rely on the power of the sun. If you have access to a sunny spot in a private yard or even a balcony, terrace, or rooftop, you can grow weed outside. You will be tied to the sun and the seasons and local weather, but you won’t have to spend a bunch of money on equipment and utilities like indoor growers.

If you’re growing weed outdoors, it’s great to find a community of cannabis growers in your area to see how others are growing in your specific climate. Local climates vary, so it can be helpful to see what strains thrive where you are, and also when other growers are popping seeds, harvesting, and more. You can also join online forums or Social media groups, but a great place to start is your local grow shop.

Benefits of growing weed outdoors

Low costs

Relying on the power of the sun, you won’t need to spend a ton of money on an outdoor grow. You’ll need some soil, fertilizer, seeds or clones, and maybe a small greenhouse to get them started. You won’t need to pay for electricity for lights, AC units, or dehumidifiers, and you can even collect rainwater.

Big yields

The sky’s the limit with outdoor plants—you can let them get as big and tall as you want, as long as they’re manageable. One plant can potentially yield between a half-pound and full-pound of dried weed! Growing a handful of hands for yourself is more than enough. With an indoor grow, your space is a lot more restricted.

Environmentally friendly

Indoor grows can be wasteful, using a ton of electricity to power all those lights, fans, and other equipment. The sun and the wind are free!

It’s fun and relaxing

Don’t underestimate the therapeutic value of gardening. It’s relaxing to spend some time outside, roll up your sleeves, and get your hands dirty for a while. And there’s nothing better than smoking something you grew yourself.

When is the best time to plant cannabis outside?

In the Northern hemisphere, outdoor weed growers usually put their plants outside in April or May, depending on the specific climate—for example, it will be a little earlier in California, and a little later in Washington state. Before then and it might be too cold for delicate seedlings.

Growers often start germinating seeds and growing seedlings inside in a warm, controlled environment weeks or months before, so that plants have longer to grow and are sturdier when they are transplanted outside in the spring.

How to set up your outdoor marijuana grow

Here are some important considerations before starting an outdoor marijuana grow.

Know the climate in your area

It’s crucial to have a good understanding of the climate in the area you’re going to grow. Cannabis is highly adaptable to various conditions, but it is susceptible in extreme weather.

Sustained temperatures above 85°F will cause your plants to stop growing, while continued temperatures below 55°F can cause damage and stunting to plants, even death.

Heavy rains and high winds can cause physical damage to plants and reduce yields, and excessive moisture can lead to mold and powdery mildew, especially during the flowering stage.

Growing cannabis outdoors in the cold

Weed plants like temperate climates, typically between 60-75°F. Anything under 50°F can slow a weed plant’s growth and negatively impact the plant. Below that and plants can freeze.

Growing cannabis outdoors in the heat

Temperatures of 75-85°F are at the high end of the hot climate for weed plants. Anything above 85°F can negatively affect plants and cause them to wilt. When it gets hot, plants will need more water than usual.

Choosing the best outdoor cannabis grow site

Once you have an understanding of the climate in your area, you’ll need to consider a few things before planting your weed.

How much sunlight do weed plants need?

Weed plants will need full, direct sun for at least 6 hours a day. You may have a backyard, but it might not be great to grow there if it doesn’t get full sun every day.  

Your cannabis plants should receive as much direct sunlight as possible, ideally during midday, when the quality of light is best. As the season changes and fall approaches, your plants will get less and less sunlight throughout the day, which will trigger the flowering stage.

Wind

Having a constant breeze is good for your plants, and especially in hot climates. But if you live in an area with a lot of high winds, consider planting near a windbreak of some sort, like a wall, fence or large shrubbery.

Privacy and security

You also want to consider privacy and security. A lot of people want to conceal their gardens from judgmental neighbors and potential thieves. Tall fences and large shrubs or trees are your best bet, unless you live in a secluded area. Also, most state laws require that you keep cannabis plants concealed from the street.

Types of outdoor grow spaces

Some growers plant in containers on balconies or rooftops that are shielded from view, while some build heavy-gauge wire cages to keep thieves and animals at bay. Whatever you decide, think about how big you want your final plant to be—outdoor cannabis plants can grow to 10 feet tall or even more, depending on how much you let them go.

Garden plot: Probably the most common outdoor growing spot, many will plant cannabis alongside other growing veggies.

Balcony: This can be a great spot if it gets good light—ideally, it faces south—and will usually get good wind. However, you may need to cover your balcony from peeping neighbors.

Roof: This can be great for sun but may have too much wind.

Choosing soil and other media for outdoor cannabis growing

Soil, at a basic level, is defined as the topmost layer of earth in which plants grow—it’s a mixture of organic remains, clay, and rock particles. Cannabis plants thrive in soil rich with organic matter, and they need good drainage. 

Most outdoor weed growers will either dig a hole and add fresh soil for the plant, or grow their weed in pots. This will allow you to better control the growing medium and the amount of nutrients your plants receive. 

You can plant directly into the ground, using the preexisting soil, but you’ll need to understand your soil’s composition and amend it accordingly. If you go this route, we recommend getting your soil tested, which will minimize headaches, and it’s easy and relatively inexpensive. A soil test will tell you the makeup and pH of your soil, any contaminants present, and will recommend materials and fertilizers to amend your soil.

Soil has three basic consistencies, in various ratios:

• Clay
• Sand
• Silt

Soil also varies in:

• pH level
• Water retention
• Texture
• Nutrient makeup
• Drainage

Silt soils

Silty soil is the ideal growing medium. It’s easy to work, warms quickly, holds moisture, has good drainage, and contains a lot of nutrients. The best silty soil is dark, crumbly loam—it’s fertile and probably won’t need any amending.

Characteristics:

• Medium granular size

Pros: 

• Naturally fertile (contains nutrients)
• Retains water
• Stabilizes plants

Cons: 

• Poor drainage
• Easily compacted

Sandy soils

Sandy soil is easy to work, drains well, and warms quickly, but it doesn’t hold nutrients well, especially in rainy environments. You’ll want to dig large holes for your plants and add compost, peat moss, or coco coir, which will help bind the soil together. 

In hot climates, sandy soil should be mulched to help with water retention and to keep roots from getting too hot.

Characteristics:

• Large granular size
• Low pH

Pros: 

• Good drainage
• Prevents compaction
• Easy to work with
• High oxygen levels

Cons: 

• Poor water retention
• Dries out quickly
• Nutrients get washed away

Clay soils

Heavy clay soils drain slowly and don’t hold oxygen well, so they will need to be heavily amended. A few weeks before you plant, dig large holes where you’ll be placing your weed plants and mix in big amounts of compost, manure, worm castings, or other decomposed organic matter. This will provide aeration and drainage, as well as nutrients for the plants.

Characteristics:

• Small granular size
• High pH

Pros: 

• Provides minerals
• Retains water
• Stabilizes plants

Cons: 

• Poor drainage
• Heavy soil
• Hard to work 

Loam soils

While some plants thrive in their native soils, which are usually one of the compositions listed above, cannabis plants are best grown in soil that includes a combination of the three consistencies above—this mixture is known as loam.

The best way to identify loamy soil is by touching it. How does it feel? Sandy soil should be difficult to compact while clay should compact into a tight ball that won’t crumble. When squeezed, loamy soils should form a loose ball that will hold its structure momentarily before breaking apart in large chunks.

Characteristics:

• Mixture of sand, silt, and clay
• Near neutral pH

Pros: 

• Drainage
• Water retention
• Naturally fertile
• Easy to work
• Nutrient retention
• Supports microorganisms
• High oxygen levels

Cons: 

• Can be costly

Most potting soils used in gardening are loam soils. If you’ve ever worked with potting soil, you’ll know that its composition is rich and diverse, and it looks dark and hearty. Beyond texture and color, the soil should smell rich and alive.

Buying the right soil for an outdoor cannabis grow

For most first-time gardeners, we recommend buying a quality potting soil that will provide your plants with enough nutrients to get them through most of their growth cycle without having to add many amendments. This pre-fertilized soil—often referred to as “super-soil”—that can grow cannabis plants from start to finish without any added nutrients if used correctly. 

You can make this yourself by combining worm castings, bat guano, and other components with a good soil and letting it sit for a few weeks, or it can be purchased pre-made from a local nursery or grow shop.

While shopping for soil, you might be overwhelmed by the options available at your local garden store. The soil type is the basic structure of your soil. From there, look at nutrients, microorganisms, and other amendments that improve the soil. Your choices will be flooded with words like:

• Perlite
• Worm castings
• Bat guano
• Biochar
• Peat moss
• Compost
• Fish meal
• Bone meal
• Glacier rock dust
• Plant food

These are just some examples of amendments commonly used in different types of soils. Heavily amended soils will have long lists that break down all organic nutrients they contain. Some companies create soils that offer a great structure with base nutrients, but allow you to fill in the gaps as you desire.

Growing containers

You may need to put all of your plants in containers if you don’t have great soil. Also, if you’re unable to perform the heavy labor needed to dig holes and amend soil, containers may be the only way for you to grow your own cannabis outdoors.

If you don’t have a suitable patch of earth to make a garden, containers can be placed on decks, patios, rooftops, and many other spots. If needed, you can move them around during the day to take advantage of the sun or to shield them from excessive heat or wind.

However, plants grown in pots, buckets, or barrels will likely be smaller than those planted in the ground because their root growth is restricted to the size of the container. In a broad sense, the size of the pot will determine the size of the plant, although it’s possible to grow large plants in small containers if proper techniques are used.

What size pot do I need?

In general, 5-gallon pots are a good size for small-to-medium outdoor plants, and 10-gallon pots or larger are recommended for big plants. Regardless of size, you’ll want to protect the roots of your plants from overheating during warm weather, as pots can quickly get hot in direct sunlight. This will severely limit the growth of your plants, so be sure to shade your containers when the sun is high in the sky.

Choosing fertilizers and nutrients for outdoor soil

Cannabis plants require a large amount of nutrients over their life cycle, mainly in the form of nitrogen, phosphorus, and potassium. How much you need to add to your plants will depend on the composition of your soil.

Typically, outdoor growers will add amendments to soil when weed plants are transplanted outside. Outdoor amendments usually come in powder form that you mix in with soil.

Start off with fertilizers that are inexpensive and readily available. Some release nutrients quickly and are easily used by the plant, while others take weeks or months to release usable nutrients. If done correctly, you can mix in a few of these products with your soil amendments to provide enough nutrients for the entire life of your plants. Most of these items can be purchased cheaply at your local nursery.

We recommend these organic fertilizers:

• Blood meal or fish meal for nitrogen
• Bone meal or bat guano for phosphorus
• Wood ash or kelp meal for potassium
• Dolomite lime for calcium and magnesium
• Epsom salts for magnesium and sulfur

There are also commercially available soil blends that already contain the proper mix of these types of ingredients.

For first-time growers, we recommend avoiding commercial fertilizers like long-release granular fertilizers. These can be used, but you need to have a good understanding of how they work and what your plants need. 

We also advise against using nutrients designed for indoor weed growing—they are generally composed of synthetic mineral salts and can damage soil bacteria.

Again, getting your soil tested can be very useful and will tell you how to amend your soil and what types and amounts of fertilizer to use. If you are unsure how much to use, be conservative, as you can always add nutrients to the top of soil—called “top dressing”—if plants start to show deficiencies.

Trevor Hennings contributed to this article.

Edited by Pat Goggins

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