Prepping the soil for an outdoor cannabis garden makes all the difference. Learn about the small details that make a high-quality harvest. Been trying to figure out what is the best soil for cannabis? Not sure where to start? Read on to learn more about different soils and what's right for you. What Soil Should I Use for Planting Autoflower Seeds? More and more cannabis growers at all levels, from hobbyist to larger scale commercial indoor and outdoor farmers are discovering the
Best Soil for an Outdoor Cannabis Garden
Correctly preparing the soil for an outdoor cannabis garden can make all the difference to the quality and size of your eventual harvest. Cannabis has specific requirements in terms of soil quality and texture. Here is a brief guide to ensuring all variables are optimized.
Choosing the best soil for cannabis means monitoring soil acidity, texture and pathogens or pests inherent in soil. Making your own soil or purchasing sterile soil gives you full control over the acidity, nutritional content and texture of the soil. At the same time, planting in the ground exposes cannabis plants to the entire living organism that is soil — and this is very difficult to create in a pot.
In any case, the growing medium is fundamental to the grow itself as well as the final harvest. Having well prepared soil can help a grower mitigate problems throughout the grow. Theoretically, if soil is well nourished, the plant should thrive with little intervention. A healthy plant necessarily starts with great soil, and without the optimum soil for growing cannabis, you will never be able to bring about an optimum harvest.
Soil texture and composition for outdoor soil
The best soil texture for cannabis is light, loamy soil that drain swell but also retains a degree of moisture. Loamy soils are a mixture of sand, silt and clay in an approximately 40:40:20 ratio:
- Sand is a major constituent of many soils, and is characterized by granular particles of rocks and minerals that measure 0.05mm to 2mm in diameter.
- Silt is finer than sand, and consists of particles measuring 0.002mm-0.05mm.
- Clay is finer still, and its particles measure less than 0.002mm in diameter.
One method of determining soil composition involves shaking soil in a jar full of water and allowing the particles to settle; a more detailed explanation can be found here.
The smaller the average particle size in soil, the harder it is for water to travel through it. You can think of it like a coffee machine. If you pack the coffee into the wand too tight, it’s near impossible for the water to come filtering through. By the same principle, sandy soils have very quick water drainage, while soils with high clay content become waterlogged easily.
If you’re using natural local soil, you can mix extra sand, silt or clay into it to improve its soil draining or retaining capabilities as needed. Drainage and soil stability may also be improved by adding gravel, which in technical terms is rock and mineral particles measuring 2m-75mm in diameter. Larger rocks can be removed where possible to avoid causing obstruction to the roots of plants.
If soil is poor, you may wish to consider buying good-quality commercial soil and mixing it into existing soil. You can also add manure, mulch, bloodmeal, bonemeal, or a range of other soil additives designed to improve nutrition release. You can even grow your plants entirely in bought commercial soil, in bags or pots so that they are not exposed to local soil.
Regulating pH of soil for growing outdoors
The optimum pH range for cannabis is between 5.5 and 6.5, making it slightly acidic. If soils are more acidic or alkaline than this, a range of deficiencies or toxicities can result. Soil that is too acidic or too alkaline disturbs a plant’s ability to absorb and use nutrients. If nutrients are not taken up in optimum ratios and quantities, your plants will not achieve the maximum quality and yield, your final harvest will suffer as a result.
Soil pH can be adjusted with a pH regulator. This is usually a solution that can be purchased from any gardening store. The most commonly used ingredient to lower pH (make it more acidic) is sulphur. Sulphur reacts with specialized bacteria commonly found in soil to create sulphuric acid, therefore acidifying the soil.
To increase pH, agricultural lime is usually added to soil. However, it isn’t necessary for cannabis cultivators to purchase sulphur or lime. These are usually available in solution at garden stores. A thorough guide to adjusting pH can be found here.
Remember that before you add a pH regulator to your soil, you first must know the current pH of your soil. This is measured with a soil pH meter. It can also be purchased from your garden store. You should only add pH regulator to your soil once you know the current state of acidity.
How to Choose the Best Outdoor Cannabis Strain
Sterilizing your outdoor soil
Sterilizing your soil by exposing it to steam can kill off many harmful bacteria, fungi and insects, while allowing several beneficial bacteria to remain alive. If purchasing good-quality commercial soil intended for growing cannabis, it is usually unnecessary to sterilize soil. However, if using local, natural soil, it may be helpful to sterilize where possible. It may also bring the added advantage of killing off any unwanted weed seeds present in the soil.
Sterilizing is a difficult and time-consuming process that is often overlooked though. If it’s not feasible to conduct this step, there are other ways to control pests. You can introduce beneficial microbes and insects to soil, as well as organic, plant-based compounds that repel or kill pests without harming the plant.
There are various techniques for sterilizing outdoor soil. Solarization is one method, and involves thoroughly tilling the soil so that it is broken up into fine pieces, watering and covering with a sheet of clear plastic.
The sheet of plastic amplifies the heat and light of the sun and allows the soil to reach high enough temperatures to kill off most undesirable microorganisms. Soil must reach temperatures of 46°C (114°F) for four to six weeks to be fully effective. It should be checked and re-tilled regularly to ensure that temperatures are sufficient and consistent.
If soil solarization is not possible due to time constraints, it may be possible to sterilize your soil by using steam. Large-scale agricultural operations make use of expensive, specialized equipment, but it is possible to use cheaper household sources of steam such as a pressure cooker to sterilize soil.
There are also methods that have been designed for smaller-scale grow operations. For example, the Hoddesdon grid method is a technique that involves layering tilled loam on a steel grid over a shallow pan of constantly-boiling water so that steam can rise through it. When temperatures reach 82-88°C (180-190°F) throughout the soil, sterilization is complete.
Growing outdoors: Pots, bags, or holes in the ground?
When growing outdoors, there are several options available: grow your plants in pots or planters, keep them in growing bags (which may be the plastic sack your commercial soil was purchased in, or may be specially-designed bags that are typically made of hessian or breathable plastic). You can also dig holes in the ground and plant directly into the soil. Outdoor soil can be optimized using the methods outlined above, or use without modification if testing shows it to be naturally optimized for growing cannabis.
If growing in pots or bags, you have the advantage of using commercially-bought soil which is not only optimized for growing cannabis but pre-sterilized to ensure that no harmful microbes are present. The downside is that your plants will be constricted by the size of their container. Pots may also require regular transplants as well as water (which they cannot receive from groundwater as plants in permeable bags or holes in the ground can).
On the other hand, digging holes in the ground and planting your young plants straight into the soil allows them to grow without constraint, and will allow roots to access the maximum amount of groundwater. Thus, they will achieve larger sizes and will require less vigilant maintenance, but may be at increased risk of exposure to soil pathogens and even contamination from agricultural run-off, for example.
Choosing the best soil for cannabis is often not as complicated as growers make it out to be. This is especially true for those who are just beginning to grow cannabis, and are not particularly concerned with yielding specific amounts of specific cannabinoids. Cannabis grows almost everywhere, and is known to grow in wet soil next to riverbeds as well as on rocky mountainsides. Well-nourished soil with the correct texture and pH is the best starting point, after which many adjustments can be made throughout the grow using nutrients and pH regulator.
Watch your plants throughout the grow, and adjust the soil as need be. Growing cannabis is a learning process that requires time and patience, and the best things are learned on the job!
Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
Learn now how to choose the best soil for growing cannabis
Most weed gardeners know that growing cannabis in soil is a common and effective growing method.
The difficulty is that growers have to peruse through many soil options and may find it challenging to determine the right option for them.
Well, sit tight! In this article, we’ll be showing you how to choose the best soil for cannabis to give your marijuana the best chances of fat buds and a huge yield.
Why is choosing the best soil for cannabis very important?
Soil is one of the three components (including water and light) needed to help a plant
Choosing the best soil is vital as, without it, a plant can’t grow effectively and may end up lacking nutrients or even under developing. Good earth also helps provide plants with the health needed to survive under challenging weather conditions.
Along with learning about temperature and humidity for growing weed, understanding soil is vital. It spells the difference between a plant that didn’t grow to one that exceeded expectations.
The components that make up the soil
Soil consists of several components and is quite complex in its makeup. Let’s look at what these are:
- Air: 25% of soil is simply air.
- Water: A further 25% of the earth is water. It’s vital for moving nutrients to the plants.
- Clay: One of the three primary materials found in soil, clay, like the other minerals, is derived from broken-down rocks.
- Sand: This is one of the primary minerals found in dirt. Minerals, in fact, make up 46% of all soil.
- Silt: The second of the primary minerals found within the soil.
- Organic matter: This makes up the remaining 4% of the earth. Soils high in organic matter are brilliant for plant growth.
Knowing what good soil is
You can identify excellent cannabis soil by looking at a few key indicators.
- Dark and loose: Dark soil is rich soil. It means that they contain plenty of organic matter, sodium, and healthy nutrients. Loose soil allows for better aeration.
- Good drainage & water retention: Good drainage means that the marijuana water can drain to the bottom well. Well-drained earth ensures that your cannabis stays wet for a reasonable amount of time. An appropriate amount of water retention is vital to keep cannabis healthy.
- The correct pH value: The ideal pH value is about 6.0 as cannabis plants thrive better in a slightly acidic environment.
- Organic matter: Organic matter is decomposed material derived from plants and animals. It helps provide nutrients and improves the water holding capacity of the soil. Examples include compost and manure.
Choosing the best soil for marijuana
The best soil depends on the conditions that you’re growing your marijuana. So, for example, what’s needed for outdoor marijuana is different from that for indoor cannabis.
Let’s break it down.
Best soil for outdoor cannabis
The benefit of growing cannabis outdoors is that your plants won’t be as restricted and can further grow their roots.
However, you’ll have to monitor and possibly change the soil’s pH level if it’s not suitable.
Cannabis plants all need nitrogen, phosphorus, and potassium in their soil ‘diet’. These nutrients will be absorbed at different rates and need to be renewed with a good marijuana fertilizer from time to time.
A dark, crumbly loam works best outdoors that’s mostly silt.
Best soil for indoor cannabis
Loamy soil is the best for indoor cannabis. An ideal mixture of 40% silt, 40% clay, and 20% sand offers a loose soil texture for adequate oxygenation and root growth. This mix also offers good water retention, drainage, and an ideal pH level of 6.0.
Best potting soil for cannabis
Firstly, it’s important to note that no matter what pot you use, always make sure that there are holes at the bottom to prevent your cannabis from drowning.
Cannabis can be effectively grown in pots using pre-packaged organic soil.
An alternative is to make what is known as a ‘super soil’ mix. You’ll have to find a super soil recipe or order a mix online. It’s a great option as it self-regulates its pH levels.
Best organic soil for cannabis
Creating the best organic soil for marijuana is tricky, but there are a few components that can drastically improve its health and efficacy:
|Component||What it offers|
|Worm castings||This is a good source of nitrogen. It’ll also give your soil the added benefit of many micronutrients.|
|Bone meal||For a source of phosphorus, this is the way to go.|
|Chicken manure||Chicken manure is an excellent source for adding nitrogen and phosphorus to your soil.|
|Bat guano||This is also a good way to get phosphorus and nitrogen into your organic soil. It also diversifies the soil’s bacteria.|
|Compost||Compost piles can be an excellent source of nutrients such as potassium.|
|Kelp meal||Both promoting microbial diversity and offering potassium, kelp meal is a great component to add to organic soil.|
Best soil for autoflowering cannabis
Autoflower cannabis seeds transition automatically from the vegetative to flowering stage regardless of the light availability.
However, for this type of cannabis, light and aerated soil is preferred. This aids the roots in growing deeper.
You can make the best soil for autoflowers from peat moss, compost, vermiculite, and coco coir.
Store-bought vs. homemade
If you’re not interested in the hassle of putting together your own soil, then you can always stop at a local shop or peruse an online store for some good-quality mix that’s ready-made.
Although homemade soil may lack on some fronts, it does offer certain benefits. Let’s take a look at what those are compared to store-bought:
|Homemade Cannabis Soil||Store-Bought Cannabis Soil|
|Greater flexibility of choice.||Already pre-packaged.|
|Generally cheaper than store-bought cannabis.||More expensive than homemade cannabis.|
|It requires more research to figure out and can be complicated.||The work to put together nutrients and research is already done for you.|
|Easier and cheaper to make in bulk.||Often comes in smaller packaging.|
How to make your own soil
Making your own soil may be preferable for many as ready-made soil mixes can be pretty expensive. Here are a few steps that you can follow to get started:
Step 1: To start with creating your marijuana soil mix, you can opt to find soil at your local gardening store. Alternatively, you can use the soil you have at home.
Step 2: Next, you’ll need to add the building blocks of cannabis: nitrogen, phosphorus, and potassium. You can find these components in worm castings, bone meal, and compost.
Step 3: Then, mix the soil. It’s as simple as that, and you’re on your way to having the best soil to grow marijuana.
Improving the soil, you already have
There are several minerals, soils, and nutrients that you can add to the soil you already have to make it suitable to grow excellent cannabis. Here are a few suggestions:
- Coco for cannabis: Coco-coir is a flexible growing medium made out of coconut shells that grants your plants the ability to grow even faster than they already are.
- Perlite: This can help loosen and provide excellent aeration to the soil and also aids in the speed of growth of the plant.
- Vermiculite: This is good for dampening the soil and raising the pH level of your cannabis.
- Worm castings: These are great for resolving nitrogen cannabis deficiencies. This nutrient-rich manure is perfect for any weed soil mix.
- Nutrients: Along with nitrogen, potassium, and phosphorus, marijuana soil also needs calcium, magnesium, copper, iron, and many others.
Before we move on to our FAQs: if you want to know more about growing, be sure to check out our marijuana for beginners guide. It offers a lot of helpful information about costs, climate, strains, and much more relating to growing marijuana.
FAQs related to best soil for cannabis
We’ve scoured the internet and put together the most frequently asked questions to help you find the best soil for growing weed.
What is the best soil for growing cannabis?
Loam is undoubtedly the best soil for growing cannabis. Its pH level is close to the ideal level of 6.0. Regrettably, it’s quite an expensive soil to buy but a worthwhile investment if you want to grow the best marijuana plants possible.
What is the best soil for outdoor cannabis?
Outdoor cannabis grows well with organic soil. You can make your own or opt to purchase a mix online or at a local garden store.
What is the best soil for indoor cannabis?
The ideal is the same as the best overall cannabis soil, which is loam. If you’re not willing to pay the price, though, you can always opt for a nice pre-packaged cannabis soil mix. Just make sure that it’s full of quality nutrients!
What is the best organic soil for cannabis?
You’ll want a soil mix that’s teaming with all the necessary micro and macronutrients needed for your plants. A nice blend of worm castings, rock dust, bone meal, bat guano, and various other soil amendments is the way to go.
What are the best nutrients for cannabis in soil?
The fundamentals are:
- Nitrogen (blood meal, ammonia, or cottonseed meal).
- Phosphate (bone meal, slag, and rock phosphate).
- Potassium (wood ashes or seaweeds).
It comes down to you
As you can see, there’s a lot to consider when choosing the best soil for growing marijuana. It depends on the type, where you’ll be growing it, and what you hope to achieve.
There are a lot of great ready-made products out there, both online and in-store. It just takes some time and research to figure out which is right for you.
Do you feel ready to start growing? Peruse the i49 website and decide on the right cannabis seeds for you to start your growing journey today.
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What Soil Should I Use for Planting Autoflower Seeds?
More and more cannabis growers at all levels, from hobbyist to larger scale commercial indoor and outdoor farmers are discovering the benefits of running autoflower strains. Why? For back yard and/or basement warriors, autoflower strains, also known “day-neutral” strains, are not terribly difficult to grow. Autoflower strains also feature a relatively compact stature. And regardless of the strain, an autoflower will start to flower 30 days after it emerges from seed. And best of all, an autoflower will reach maturity in just 6 weeks!
The decision to run an autoflower in your grow tent or a while field is not one to be taken without proper planning: autoflower strains have the own set of unique cultivation requirements. As such, running an autoflower strain is a strategy (what you’re going to do) requiring you execute against well-defined autoflower tactics (how you’re going to achieve your strategy).
Here’s the thing. Until just a few years ago, when commercial cannabis became fully legal, autoflower strains remained largely hidden in the cannabis underground in California, where a select few advanced autoflower geneticists were quietly advancing the autoflower arts. Even today, a good deal of mystery exists about growing an autoflower; and very few have adopted an autoflower strategy often for lack of authoritative information. This includes from where you can get reliable autoflower seeds, to how you germinate autoflower seeds, and to what and how much nutrition autoflower strains require. And what kind of deliverable can be expected from an autoflower installation.
The good news is as more growers plant these new autoflower strains, a knowledge base of information related to successful autoflower cultivation is coming to light. And, a select few autoflower cultivators are rising to the challenge of creating reliable feminized autoflower genetics, and are providing some rather kick-ass autoflower strains suitable to both home and commercial autoflower grows.
To best understand what it takes to grow an autoflower strain versus the more prevalent photoperiod strains, it helps to have a basic understanding about why running an autoflower is worthy of your consideration, and what makes an autoflower different from its long-standing cannabis photoperiod predecessor.
While there are many legends of how the first autoflower strains came about and by whom, the genesis of autoflower strains is largely based in economics, and the desire of cultivators to achieve more harvests of quality cannabis in a growing season. It also came from a desire from autoflower growers to beat the majority of cultivators growing photoperiod crops to market: with proper autoflower cultivation management, autoflowers can typically be harvested in mid-summer, well before the glut of photoperiod cannabis products hits the market. As such, autoflower strains have been proven to better hold their value, while giving growers more options and predictability.
Now unknown by many who believe cannabis comes in either sativa or indica varieties of some permutation thereof, a third subspecies of cannabis exists, known as Cannabis ruderalis.
Cannabis ruderalis is a compact plant thought to have responded to the survival of the fittest existence as it grew near the borders of Siberia. Unlike photoperiod cannabis strains that react to the duration of sunlight to create flowers which in turn create seeds and thus ensure their reproduction, Ruderalis genetics respond to the need to survival by triggering the flowering response without a need for a specific light style and/or duration. Ruderalis are tough, and do not require the rich soils of its photoperiod cousins, whose roots were in more tropical climates.
Without getting technical, the first autoflower strains came about by breeding indica and sativa strains with ruderalis plants to create an autoflower breed that exhibited the flower mass and potency characteristics of its indica/sativa parents while providing the autoflower characteristic of fast seed-to-harvest cycles.
Now as you can imagine, given the short season and rather difficult, most often peat-based soils in which ruderalis strains grew required it to adapt to survive.
So it is when a grower wants to cultivate an autoflower strain. The fact is, while not all autoflower strains are alike, for the most part, an autoflower will prefer a grow medium that is light and not compacted as many commercially available grow mediums used for the autoflower’ cousin photoperiod strains.
What’s more the ‘soil’ you use for an autoflower strain is typically low in resident nutrients; in no instance should a ‘live’ soil or even a dense and rich organic soil be used or you’ll burn the autyoflower root zone in no time at all
Rather, when growing an autoflower, it’s best to have control of the inputs of water and nutrition so the autoflower can recognize and respond on its own volition to its flowering instincts.
And indeed, it’s very important you manage watering an autoflower. You see, an autoflower plant can easily be “drowned” when its root zone is deprived of oxygen. In fact, an autoflower really hates excess moisture and as such, should be allowed to dry somewhat (but not ever fully) so its roots reach out for sustenance.
Thus, when establishing an autoflower, its best to use a peat-based ‘soil-less” medium such as Pro-Mix, with light amendments to bring up its nutritional value. Because to be sure, an autoflower does require water and fuel to grow; but most autoflower strains will always require less inputs than tropical strains.
One such amendment for autoflower propagation is worm casings; another would be a rich organic soil. However, you don’t mix it with the primary autoflower ‘soil’ as you would for a photoperiod. Rather, when preparing a pot, ideally one with breathability such as a fabric or air pot (to encourage autoflower root zone oxygenation), layer the pot with a base of drainage pebbles, then add a layer of worm casings or rich soil, and top with at least 50% of a soil-less or loosely packed medium.
Once you’ve transplanted your early autoflower starts, water around the stalk of the plant so the autoflower roots reach out for moisture. Real care should be given to the pH of your water: it’s critical to stay within the 5.8 – 6.6 range so microbes in your grow media can convert form an autoflower can uptake and use for growth. In this case, a simple pH meter is an indispensable tool for guarding the health of your autoflower.
Now one of the biggest temptations for autoflower growers is to over-pander to them. Resist this temptation at all costs. Which is not to say you should ignore the care of your autoflower strains; you should not.
But, like all plant growing endeavors, growing a quality autoflower is all about paying attention to your ‘ladies” and how they react to inputs, including light.
Do so, and your autoflower adventures will yield the magical outcomes of your dreams.