Page content

Best Soil For Outdoor Marijuana Plants

Best Soil For Outdoor Marijuana Plants

When it comes to the best soil mixture, growing marijuana is more complex than simply sticking the seeds into the ground. You have to find the method that works best for you, whether it’s planting your cannabis directly into the earth, or using a bucket or other container for it. Both of these methods work fine, and, as with anything, each has its own set of pros and cons.

In this article, we will cover the methods and techniques for growing your cannabis, as well as the basics of soil information. The greatest benefit of soil is its ability to provide nutrients to your plants so we will cover which nutrients your plants need and how to maintain this balance as well.


Planting in containers or in the ground

Outdoor cannabis growing basic soil requirements

You might want to plant your marijuana in containers if you want to focus on the soil conditions and don’t want to worry about how to prepare your planting site ahead of time.

You can create your own special mix of soil in order to make sure your plants are getting lots of nutrients. This helps you in the long run because it means you will not have to add in extra additives later on in your plant’s life. Click here if you want to buy soil directly.

You also won’t need to be as particular about the conditions of your growing site, so you will have more options available and might, therefore, be better able to choose a well-hidden place.

Download my free marijuana grow guide at this link for more outdoor growing tips

If you prefer the more natural route, however, you also will be greeted with plenty of benefits. For example, if the soil is high quality, you will have access to quite a few more nutrients than with container planting.

The roots of your marijuana plants can grow extremely deep and thick since they will not be limited by a container. This method also has its own set of disadvantages, however, as it means you will need a lot more preparation in advance.

You will have to till the soil and change the pH level of the current soil that is located there. You hard work would pay off, however, since your extra nutrients won’t wash away as easily from rain or watering, and the roots will take in those nutrients whenever they need to.

Regardless of which method of planting you choose to use, the soil will need to be rich in nutrients and well balanced.

The best soil mixture for outdoor plants

Best soil mixture for outdoor cannabis plants

The “you are what you eat” concept applies to people as well as plants. This is what makes soil so important in growing high-quality cannabis plants. The better the soil, the better your harvest.

So what makes a soil higher quality? If you hold it in your hands, it should feel fluffy. It should be able to drain well, as well as already possess plenty of nutrients.

If you are using large pots for planting the marijuana seeds, you have a much easier way of controlling the quality of your soil. You can use things such as compost or store-bought fertilizer to form a base that is fertile and rich - perfect for planting.

If you are planting in the ground instead, you will need to prepare and test the soil to make sure that it is conducive for growing your plants.

Best nutrients for outdoor soil

Soil mix cannabis outdoor container

Cannabis plants will need plenty of some nutrients from the beginning of its life until its end, or else its yield will not be optimum. Three foundational nutrients that you will need to focus on are nitrogen (N), potassium (K), and phosphorus (P). The fewer these nutrients, the less weed you will get.

When looking at fertilizers in the store, you should be able to see exact percentages of each nutrient (listed in N-P-K order). These three nutrients must always be present, throughout the entire lifespan of your cannabis plants. You must carefully maintain the balance of these nutrients, regardless of which life stage your plants are in.

Maintaining this balance is made easier by using store-bought fertilizer and the container planting method. This is because the fertilizer mix probably already has a  pH value of 6, which is not too acidic nor too alkaline, making it the perfect pH level for marijuana plants.

Download my free marijuana grow guide at this link for more growing tips

Do not be surprised, however, if your marijuana plants start showing signs of a lacking of one or more nutrients - this is simply because plants don’t use them all up at the same rate. Some nutrients are consumed faster than others, which means you will have to replenish the ones that are consumed at a faster rate. You can do this via feeding into the soil, or just with adding it into your normal watering.

So how can you identify a plant that needs a specific nutrient? You can see and feel differences that will tell you which nutrient your plants are lacking.

Best soil for planting in containers

Best soil mixture container outdoor cannabis plants

Although container planting is easier in many ways, it also means there is less room for error and more maintenance required on your part. You are the only thing that is providing nutrients for these plants, so you need to make sure you are constantly aware and observant of your plants’ needs.

Do you think that container planting is the way for you? (click here for the best pots) If that is the case, you will need to be careful of a few key factors. To choose the correct type of container, it’s always good to go for the lightest one possible. The reason for this is simple: you will need to move your pots multiple times, and lighter containers make that movement easier for you.

Try out a plastic bucket that is about five gallons in volume.  You can find these from restaurants that have used them, which is good because it means there were no hazardous materials stored in them at any time.

Download my free marijuana grow guide at this link for more outdoor growing tips

By contrast, clay pots are definitely not ideal. They are also an unnecessary expense and even absorb some of the water that your cannabis plants could use. If you do happen to use clay pots, make sure you spray the pot with water so that it isn’t absorbing any of that plant’s water, especially during the hot, dry summer season.

You can also find grow bags, which can be a good substitute for clay pots or plastic buckets. They can hold quite a bit of soil and are also fairly durable. The only potential issue with grow bags is that they allow for a lot more bumping around of the plant and its roots whenever you need to move it.

So if you choose to use them, be very careful whenever you need to transport plants inside of them. If the roots are damaged, your plant will need to focus all of its energy on repairing the roots rather than growing, so it would then slow down its growth.

Whichever container you decide to use, make sure it has holes in the bottom so any extra water can drain out, so you don’t drown your plants. Just make sure that these holes are not too big, otherwise soil could tumble out the bottom. Another idea that could work is to keep a few rocks (not too many) inside of the soil to help with drainage.

Best soil for planting in the ground

Best soil mix ground outdoor cannabis

If you are going with the natural soil route, you will need to understand what the soil is like near your marijuana growing site, as well as any nearby plants. Soil can come in three major types: clay, sandy, and loamy. You can find out which kind your soil is just by asking at a gardening center what type is common in the area.

You could also pick up a few cups of the soil and bring it into the gardening center. That way, they can see it and tell you exactly what it is.

Growing marijuana in clay soil

Clay soil outdoor cannabis growing

Clay soils are generally heavier and are better able to retain water. This isn’t all good, however, as such a dense soil can also prevent water from transporting through, so it can keep the roots from growing as fast as they would otherwise. This type of soil is found all around the world, and, therefore, no matter where you are, you will need to be prepared to deal with this kind of soil.

Before you plant your cannabis plants into the ground, you should dig large holes for planting. These holes should be quite large - a few feet across, in which you can add in compost mixes or decent fertilizers. This will keep the clay soils from inhibiting your marijuana plants’ growth too much.

Growing marijuana in sandy soil

Sandy soil outdoor cannabis growing

Sandy soil is usually located in dryer climates, generally near the coast. Plenty of areas inland also can house sandy soils. As you could guess from the name, sandy soils are more loosely packed and, therefore, allow plenty of air and water movement, as well as root growth. This is useful for the cannabis roots to search and locate minerals that are not as easy to find.

Since water can move so freely in sandy soils, it cannot be retained as well as with clay soils. This presents a different sort of problem, one you also will need to prepare in advance for. This preparation will let your marijuana plants grow bigger and provide a larger yield. You can use a moist compost to help the soil stick together more effectively, which is what it needs to retain more water.

Because sandy soils are most commonly found in warmer climates, it also could be a good idea to add some loose fertilizer, as well as planter’s mulch. These two ingredients should ensure that the soil remains cool, despite the warmth of the air around it.

Growing marijuana in loamy soil

Loamy soil outdoor cannabis growing

Perhaps one of the easiest soils to work with, loamy soils both retain water well and allow for freedom of movement for water and root growth. They are the perfect combination of clay and sandy soil types. These soils are fertile and moist.

Always be aware, though, that just because the structure of loamy soil is user-friendly, it doesn’t mean that it contains all the nutrients that your marijuana plants are going to need. It may even begin rich with nutrients, but then later lose some of the nutrient quality it had. Especially during your marijuana plants’ vegetative growth phase, you will probably need to add some nutrients.

Test your outdoor soil mixture

Test outdoor soil mixture cannabis

Identifying what type of soil your growing site has is not as easy as it might sound at first. Every soil is some sort of compilation of the three soil types described above. Before you can actually test exactly what your soil is made of, you should get a general clue about what type of soil it might be.

Any soil, even if you’re putting it in a pot, should be tested (quick link to article Measure pH of soil). Even if you buy fertilizer in your local gardening center, it’s always a good idea to test the pH level to make sure it isn’t too acidic. In order to check the pH, you will have to buy a pH tester.

So what do the pH levels mean, exactly? Your tester will show you some number between 1 and 14. The lower the number, the more acidic it is; if it’s on the higher end, it’s more alkaline. If it’s 7, it’s exactly neutral - which is roughly ideal for growing marijuana plants. Although the scale may seem small, the value of the difference between two different numbers is tenfold. For example, if your soil has a pH value of 5, it is actually ten times more acidic than if it had the pH value of 6. To go one step further, your soil with a pH level of 5 is a hundred times more acidic than if it had the pH value of 7.

You marijuana plants will be happiest if the soil’s pH level is between 5.5 and 6. If it is, the marijuana plants will be able to act as efficiently as possible when they are taking in nutrients from the soil.

Download my free marijuana grow guide at this link for more growing tips

If the soil is too acidic or has a very low number on the pH scale, it means that salts would restrict nutrients from being absorbed, or it might keep your plants from breaking down these nutrients, which will mean the roots can’t access them. You could also see some toxic buildup in this situation, which could keep roots from being able to absorb water.

If the soil is too alkaline, it could also restrict the availability or breaking down of nutrients for your cannabis plants. Instead, the nutrients could get flushed away as soon as you water them.

If you test soil and it is fairly alkaline (between 7.1 and 7.4), it could actually be helpful during the vegetative growth stage. Of course, this depends on the overall condition of the soil, as well as whether you have been adding other nutrients when required. As soon as your plant reaches its flowering phase, you will need to be sure that the pH level is as close to 7 as it can get.

How exactly do you measure the pH value? You can use three different ways that all work pretty well. Soil test kits, litmus paper, and electronic pH testers are all easy to find at any gardening center or hardware store. Make sure you take more than one sample when you test the pH and be sure to follow the directions given with your chosen pH testing device. The soil test kits mix the soil and a chemical solution together in order to measure what the pH level is, as well as the main nutrient content.

You can “read” it by looking at the color that comes out and comparing it to a color chart that is included with the kit. You have to be sure you fully understand what you’re doing and how it all functions. If you can, try using it to first test soil that you already know is a neutral pH level. The product that is the easiest to use is the electronic tester. It produces clear and precise results and is the most accurate and precise device you can use.

All in all, never underestimate the importance of soil and don’t ever get lazy when you’re choosing and testing soil. Test it regularly enough so that you can ensure it’s consistently the right pH level for your plants, and have a complete understanding of the soil type so you can prepare it accordingly. Happy growing!

Thanks for reading. Please leave comments or questions below and don't forget to download my free grow bible


Download the Ultimate Grow Guide for FREE!
Learn the basics of growing marijuana and get started today
  • How to get the biggest yields from cannabis plants
  • What you need to get started, without wasting money
  • The most common mistakes you do not have to make
We guarantee 100% privacy.

Comment Section

25 thoughts on “Best Soil For Outdoor Marijuana Plants

By Andrew Tasker on 7 June 2014

I feel you should recommend that people NOT use commercial, chemical fertilizers since the application of such fertilizer effectively wipes out a lot of helpful bacteria and little critters that help aerate and enrich the soil. The best Ph for marijuana is not 7, as it is for most veggies, but 5.8 to 6.5. I made this mistake myself, so I know!

By steverino on 12 December 2014

My seedlings are now 4 weeks old, in 70 degree F grow room, 300W appollo horticulture LED light, and have 1/2 sandy soil 1/2 potting soil, and they refuse to grow. I will try your recommendation of root stimulator to see if that helps.

By raymond on 12 April 2015

use bat guano it makes just about any soil usable and it makes the plant grow 100 times faster

By Nora Power on 13 August 2015

I have a question. I have a plant,it is about 3 ft high and is strong and healthy,however I don't see any buds or hairs on it. It is very leafy and green. I also have one that is about a ft high,doesn't look that healthy and is a paler green,quit spindly but is already starting to produce hairs and what looks like tiny buds. They are both in large containers and live in the exact same soil,get the same amount of sun and water. Which one should I be concerned about,or should I be concerned about both of them?
Thank you .

By latewood on 19 August 2015


It is really hard to answer you without hazarding a guess.

Perhaps you will consider joining our "Support forum" and posting this in a topic. We would love to help you figure out the issue at hand.

By JIM on 5 September 2015


By latewood on 7 September 2015

All you can do to lower PH, which is really not necessary; Would be to water with a lower PH'd solution

By Jeffrey McConnaughey on 12 February 2018

Why don't you mention the proper depth for soil testing and Ca is more important than P unless you're growing seeds. Don't lower your solution pH to acidify mineral soil, use the right amendments, latewood!

By Juan Navarro on 20 May 2016

What are those sticks in the pots? What are they for and how do you attach them to the plant

By Chuck Johnson on 22 May 2016

I add Organic Minerals 77+ from Mineralmaxx to gain flavor and density. They send them USPS

By Brock on 23 July 2016

I am confused after reading this... You say... "If it’s 7, it’s exactly neutral – which is roughly ideal for growing marijuana plants."...

And then you say..." You marijuana plants will be happiest if the soil’s pH level is between 5.5 and 6."

Confucius say... Huh, wtf? Please clarify

By latewood.ILGM on 25 July 2016

Juan Navarro,

Those appear to be typical Bamboo sticks found in any garden center. Typically they are placed in the soil and you just prop your foliage onto them for support.

If you wanted to attach them, it can be done using round tomato clips

By latewood.ILGM on 25 July 2016


PH 7 or "neutral PH" is for soil plants.

5.6-8.0 PH (slightly acidic) is used for the PH in hydroponics growing..

Perhaps you should join our grow support forum. We have many helpful and friendly members and a few experts to guide you along. Happy growing, lw

By Roxx on 6 August 2016

I live in Oregon, and Im about to grow commercially on a 30,000sq ft. outdoors area, and I know we will have around 1500 plants. I have access to 100,000lbs of horse manure thats been composted over many years. Should I mix this with the soil, and if so, how should I go about it on this scale of things ? I also, since I dont know the ph of the land/soil yet, wondered if theres a certain kind of soil I should ask for from a company that will deliver dumptruck loads of it to my grow area ?

Should I grow Sativa or Indica outdoors for a better yeild ?

What are the top yeilding strains for outdoors ?
I downloaded your growbook, and truly appreciate it, and what youre doing for all of us with your knowledge and forums such as this.

Thank you very much.

If anyone is reading this, (especially if youre in Oregon)., and can help me with the info I need, feel free to text me @ 5-zero-3, four-8-four,-zero-two--seven-2.

Thank you so much.



Thank you for any help.

By Roy ILGM on 8 August 2016

Hey Roxx, that's a mighty project you have in the works. Though I would love to get into your questions over here, the better place to go about this is on our grow support forum. Our team as well as fellow growers can help you out over there. Hope to see you soon!

By vernon bobo on 2 March 2017

When you take aPH level if one is off what do you put in the soil to get it right..........DoYou go buy some spil that has already has it in it//////////////

By latewood_ILGM on 6 March 2017


Dolomitic Lime is used to buffer PH in soil mixes.

Happy growing.

By Aleksey on 3 May 2018

"Three foundational nutrients that you will need to focus on are nitrogen (N), potassium (P), and phosphorus (K). "
It's a typo. Should be: potassium (K), and phosphorus (P).

By latewood_ILGM on 4 May 2018

Thanks! I will shoot a message to the Admin.

Leave a Reply