What is Good Soil For Growing Cannabis? When it comes to growing cannabis in soil, unless you’re using a brand that is known for making soil that is specifically cannabis-friendly, there are a What is the best soil for cannabis growing and is it easier/cheaper to make it yourself or buy it? Read on to find out more about the best soil
What is Good Soil For Growing Cannabis?
When it comes to growing cannabis in soil, unless you’re using a brand that is known for making soil that is specifically cannabis-friendly, there are a few things that you need to consider before starting a grow.
What should you look for in good cannabis soil?
I think most growers agree a good cannabis soil should look dark and rich, with a loose texture that drains well and can hold water without getting muddy (you want wet soil, not dirt-batter!). But beyond that, what do you look for?
The following video shows the soil texture you want (this is Coco Loco, an excellent soil for growing cannabis)
Some growers choose an amended and composted “hot” soil that slowly releases nutrients over time. With this type of soil, you typically just add water or natural supplements like worm tea from seed to harvest. Other growers prefer a lighter potting mix so they have more control, and give nutrients in the water once the plant roots have used up the nutrients in the soil. But which brands can you trust?
Some popular soil examples that I’ve used with good results include:
- Almost any organic soil potting mix – If you can’t order special soil online, ask for the best soil at your local gardening store. You can use almost any organic soil potting mix to grow cannabis. I say “organic” because that cuts out a lot of potentially problematic ingredients like slow-release chemical nutrients (which often cause nutrient issues in the flowering stage by delivering too much Nitrogen). If asked what you’re using it for, say tomatoes. You should plan to start adding extra nutrients in the water by the time a plant is a few weeks old as the roots will quickly use up everything. Try to look for soil with a rich and dark but loose texture. It’s a good sign if you see little white pebbles mixed in (this is perlite, which makes soil drain better). If a soil looks like dirt or mud, it’s no good!
- Roots Organics Original – This was the first soil mix I ever used to grow cannabis and I had a great experience. I’ve moved on to Fox Farm products because they were available at my local hydroponics store, and now I’m hooked on Coco Loco. But Roots Organics Original soil has been around for a while because it works great. As with most soil mixes, you will need to supplement plants with additional nutrients after a few weeks.
- Fox Farm Happy Frog soil– This soil mix is relatively light on nutrients so it’s great for seedlings. It’s also suitable if you plan to give nutrients in the water from seed to harvest. If you don’t add extra nutrients, your plants will use everything in the soil up quickly.
- Fox Farm Coco Loco soil– A coco-based soil mix with enough nutrients to last your plants for a few weeks. With Coco Loco, you should start supplementing with extra nutrients once plants are 2-3 weeks old. I personally like Coco Loco the best of any soil mix I’ve used. You can use it by itself and it’s also my favorite base potting mix for a “just add water” super soil grow. I feel like plants tend to grow happy and healthy while being more resistant to over or under-watering compared to the other soil mixes I’ve tried. It’s great soil for other types of crops too.
- Fox Farm Ocean Forest soil– A “hot” soil mix with lots of nutrients packed inside. You can start seedlings directly in this mix though they may show signs of nutrient burn at first until they get adjusted. Ocean Forest has enough nutrients to last your plants quite a while, though you likely should still give extra flowering nutrients once your plants start making buds in order to get the best yields, density, and bud quality. Cannabis plants need a surprisingly lot of nutrients in the flowering stage and you don’t want to starve the plants right as buds are forming.
Recommended soil nutrients:
– These 3 bottles include everything your plants need from seed to harvest. The FF trio produces superb weed with any high-quality soil.
- Learn about other cannabis-friendly nutrients
Important Cannabis Soil Considerations
- Drainage Ability
- Water Retention
Although that list looks vague and complicated at the same time, the requirements you want to meet are actually pretty simple; let me break it down!
Texture, Drainage & Water Retention
It’s easy to get caught up thinking about what nutrients and amendments are in the soil, and those are important, but perhaps the most important aspect of any soil is actually its texture, ability to drain, and overall water “holding” ability.
In order for a cannabis plant to grow and thrive, it needs a good mix of both water and oxygen at the roots at all times! Too much water and the plant roots can’t get enough oxygen (lack of oxygen at the roots is why plants get droopy from overwatering) but on the flip side if there’s not enough water retention the roots can be injured from drying out too quickly!
What gets the best results for growing cannabis is a soil with a light texture that is good at retaining water…but not too much!
Note: Don’t worry, there’ll be examples of good and bad soil in just a bit!
Signs of Good Cannabis Soil
- Appears dark and rich
- Loose texture
- Drains well (doesn’t make a pool on top of your soil for more than a couple of seconds and doesn’t take forever to drain out the bottom)
- Holds water without getting muddy (you want wet soil, not dirt-batter)
Example of “Good” Cannabis Soil Ingredients
Note: You’ll likely never see any soil mix with ALL those ingredients, but I wanted to share examples of common cannabis-friendly ingredients and amendments that often appear on the label of good soil
If you get the soil part right, you have almost everything you need to get to harvest! With the correct texture, drainage and water retention, you’ve got a perfect base. Add good soil cannabis nutrients, especially in the budding phase, and you should get to harvest with great results!
Example of happy marijuana plants in good soil!
More About Common Amendments to Alter Texture, Drainage & Water Retention of Soil
Perlite is one of the most common soil amendments. It is highly recommended for any soil mix that doesn’t have some already.
- Very light, airy white “rocks” that feel almost like popcorn and add oxygen while increasing overall drainage ability.
- Add perlite to the mix (10-40% of the total volume). Use less perlite if you want better water retention and don’t plan on using a lot of extra nutrients. This is because a lot of extra perlite can cause the nutrients leach out faster from the soil. Add higher levels of perlite if you want to use a lot of added nutrients or supplements without burning your plants (since perlite helps prevent nutrient buildup).
Vermiculite “lightens up” heavy soil and improves water retention.
- Some growers use perlite and vermiculite interchangeably, though they’re not exactly the same. Vermiculite holds water much better than perlite, but is not as effective at adding aeration and drainage.
- Some growers use a little bit of both. If you go high with vermiculite, you don’t want to go as high with perlite and vice versa. Together, perlite and vermiculite should never make up more than 50% of your soil!
Coco coir is made from coconut husks. It can be purchased as loose coco coir, in an amended potting mix, or as coco bricks which needs to be rehydrated before use (learn how to re-hydrate coco bricks). Sometimes you’ll find a “soil” mix that is pretty much all coco plus amendments, and these can be a great choice for cannabis. Coco has some unique properties that make it a good supplement for cannabis soil mixtures.
- Coco improves water retention, but doesn’t make soil heavy.
- Roots tend to develop faster and plants are less likely to suffer from overwatering in coco coir.
- Some growers grow in pure coco, but if you’re adding it to a soil mix as an amendment, you might add 10-30% coco coir.
Worm castings is a nice way of saying worm poop, and cannabis plants love it!
- Improves texture, drainage and moisture retention
- Add a natural source of nutrients that breaks down slowly
- Usually contains high levels of beneficial micro-organisms due to going through a worm’s digestive system
- Add up to 30% worm castings in your soil (although it contains nutrients, it’s gentle enough that it’s unlikely to burn your plants even if you add too much)
Now here are a few examples of good and bad cannabis soil so you can see the texture you’re looking for!
Good Cannabis Soil
Rich and light composted soil. Since this soil doesn’t have a lot of perlite, it’s a good choice for a grower who doesn’t want to add a lot of extra nutrients or supplements in the water.
Good Cannabis Soil
Another light, rich soil mix with great drainage. Although there is a wood chip in this picture, for the most part the mix is completely composted and broken down. It’s normal to see some wood pieces in composted soil, but you don’t want to have to wait for a lot of wood to break down while your plants are growing – you want all that rich nutrient goodness to be readily available to your plant roots
Good Cannabis Soil
This soil has quite a bit of perlite, which is a good choice if you plan to feed heavily with nutrients and supplements since the extra perlite prevents nutrient buildup in the soil
Good Cannabis Soil
The plant is growing in organic, composted “super soil” which has enough amendments to last your entire grow, so the only thing you do is add water!
Here’s organic “super” soil up close
Bad Cannabis Soil
This soil is muddy, clumpy and waterlogged. It retains too much moisture, which makes it really easy to overwater your plants.
Bad Cannabis Soil
Cannabis soil should not have a whole lot of big visible wood chips in it. That means the soil hasn’t been fully composted, and all the nutrients and goodness in that wood is mostly unavailable to your plants.
Bad Cannabis Soil
Although this seedling is over a month old, it has stayed tiny. Its growth is stunted by the thick heavy soil that holds way too much water and not enough air. Note how some of the soil looks like one solid object.
Bad Cannabis Soil
Don’t use dirt from outside! It almost never works, especially if it looks like this!
Suggested Brands for Cannabis Soil
Fox Farm Ocean Forest Soil
Fox Farm has been around for over 30 years and makes some of the most common types of “cannabis soil” (at least in the US). They have several great soil mixes, including “Happy Frog” which is a great choice for seedlings and clones.
Their Ocean Forest soil mix is “hotter” soil (higher levels of nutrients) that contains ingredients that cannabis plants love, including earthworm castings, bat guano, fish meal and crab meal. The nutrients contained in the soil will provide everything your plant needs for several weeks. Although it might give young seedlings just a touch of nutrient burn at first, they can be started in Ocean Forest soil and will soon be able to use the nutrients and start growing quickly. Some growers might put a little big of Happy Frog on top of a container of Ocean Forest, just to make it a little more gentle for seedlings the first week or two.
If you are willing to keep transplanting to bigger pots as your plant uses up the nutrients in the soil, you don’t need to supplement with extra nutrients. However, even if you grow in the same pot from seed to harvest, Fox Farm offers a complete nutrient system that is also formulated for plants like cannabis and goes perfectly with their soil to make sure your plant is getting the right levels of nutrients throughout its life.
This plant is growing in Fox Farm Ocean Forest Soil
Kind “Super” Soil (Living Soil)
When cannabis growers talk about “super” soil, they’re usually referring to soil that has been amended with slow-releasing organic nutrient sources, and then composted for several months (learn more about super soil).
The composting process creates a “living” soil that is full of microorganisms in the rhizosphere (area around the roots). Properly composted soil has nutrient sources that slowly break down over the course of your plant’s lifecycle. It very closely mimics what happens in nature.
Super Soil has a colony of micro-organisms living in the soil which form a symbiotic relationship with your plant roots. They deliver nutrients to your plant, and in return they eat the sugars that get secreted by your roots!
The “micro-herd” in the soil delivers nutrients directly to your plants. As long as you’re using decent water, you usually don’t need to worry about pH or other things that can disrupt nutrient absorption in regular soil.
However, when growing with Super Soil, it’s a good idea to avoid watering too much at a time, as extra runoff waterwill drain away some of the nutrinets. Try to give just enough water to saturate the soil with very little extra coming out the bottom. Since you won’t be adding more nutrients through the grow, you want to conserve what’s in the soil!
Nugbuckets is a famous organic soil grower! Check out his plants!
Organic Potting Mix
This is what kind of soil to get if you don’t have any “good” soil available, but want something that is known to work for growing cannabis.
Generally, anything labeled as an “organic potting mix” will work. This type of mix hasn’t been amended with chemical slow-release nutrients, which is one of the main things you want to avoid with soil for cannabis. I know it sounds like heresy, but even the Miracle-Gro version of “organic potting mix” will work okay, because unlike their original potting mix it doesn’t contain chemical nutrients (though it still has poor drainage and moisture retention – almost any other type of organic potting mix is better!).
Usually an organic potting mix does not have enough nutrients to last your plants for more than a few weeks, so it’s a good idea to always supplement with cannabis-friendly nutrients, especially in the flowering stage when your plant is making buds and needs lots of extra Phosphorus and Potassium.
Espona Organic Potting Mix is found in many stores in the US, and works for growing cannabis!
What to Watch Out For With Any Soil Mix At the Store
- Look At and Touch It If You Can! You already have an idea what soil should look and feel like, but here’s a test: If you form the soil into a ball, it should stick together loosely, but it should also easily fall apart again if you squeeze it.
- No “Time Release” Chemical Nutrients in the Soil – These types of soil slowly release nutrients over the course of months, which provides too much Nitrogen in the flowering stage and could possibly impair overall bud growth.
- Soil Should Appear Dark and Rich – Pale, crumbly or sandy soil usually doesn’t have a lot of nutrient content that the plant roots can get to.
- Soil Has Little White Rocks In It (Perlite), if you see white, almost fluffy rocks dispersed through the soil like popcorn, that is usually a good sign because it means this potting mix was intended to have good drainage.
- Soil Isn’t “Heavy” – Cannabis grows best in soil with a light airy texture and great drainage, which may seem almost fluffy when it’s dry.
- Example of “Good” Soil Ingredients – Composted forest humus, sandy loam, sphagnum peat moss, coco coir (sometimes labeled coco fiber), perlite, earthworm castings, bat guano, fish meal, crab meal, bone meal, blood meal, Azomite, pumice, kelp, dolomite lime, mycorrhizae and leonardite. That’s not everything, just examples of cannabis-friendly ingredients you see the most often
- Examples of “Bad” Soil Ingredients – You don’t want to see wood or bark on the label if it doesn’t say it’s been composted first. Also if you see just the word “fertilizer” in the ingredients that’s often code for slow-release chemical nutrients, which you don’t want!
Try to get soil that looks like this!
I hope this soil tutorial helps you find the right soil for your cannabis setup!
How to choose the best soil for cannabis
Growing your own cannabis in soil is regarded by many as one of the easiest ways to produce high quality crops of delicious tasting buds. But what is the best soil for cannabis indoor growers? What about the best type of soil for outdoor cannabis? The best soil for cannabis combines excellent nutrition and good water retaining properties along with good drainage and an optimum pH.
What are the main traits of the best soil for cannabis?
The best soil for growing cannabis has several important functions to perform in order to allow healthy growth of the cannabis plant and the roots. There is a huge range of options from cheap supermarket soil to expensively blended specialist soils. Not all of these are ideal for growing cannabis. Here are some of the most important features for anyone seeking the best soil for cannabis growing:
Cannabis doesn’t grow well in heavily compacted, dense soils. The best soil mix for cannabis tends to be light and airy. This allows good levels of root oxygenation, especially when combined with air-pots or porous fabric root sacks. Healthy cannabis roots will thrive in a light, aerated soil.
|Cannabis roots. The importance of root health for cannabis growth|
A perfect soil mix for cannabis allows good drainage. Waterlogged soil results in poor root health and subsequent slow growth. If you water your plants and notice surface water forming in pools it is an indication that your soil may have poor drainage.
The best soil for cannabis has good drainage qualities but at the same time it is able to retain some moisture for the roots to absorb.
The best ph for cannabis in soil around 6. Some growers ask ‘how to test soil ph for cannabis?’ You can buy specialist kits which measure soil pH, though many soil growers have never worried about testing pH. To some extent soil is self-buffering, meaning that soil growers need not worry about e.g. pH-adjusting their nutrients in the way that many hydroponic growers have to. Using a larger plant container with more grow medium enlarges the buffer zone and is the preferred approach by many soil-using cannabis growers.
Most soils contain a reasonable level of nutrients. These eventually become depleted, requiring the grower to use perhaps a bloom nutrient as the plant flowers. Nitrogen (N), Potassium (K) and Phosphorus (P) are the main nutrients, but there are plenty of other important trace nutrients which are also required.
Some growers like to avoid having to feed a bloom nutrient. Instead they try to make the best organic soil for cannabis which can feed the plant for the bulk of it’s life.
This can be done with slow release organic nutrients from companies such as BioTabs. Simply mix the slow release organic nutrients into your soil mix. One tip is to use a large initial soil container (e.g. 50 litres or more). With such a large reserve of nutrients in a large container of soil you may be able to avoid the worry of bloom nutrients for much (or even all) of your grow.
|A visual guide to cannabis nutrient deficiencies|
Organic soil vs soil mix
A good organic soil is often produced with generous levels of compost, peat and slow release nutrients which are broken down in the soil by beneficial bacteria. Some of these specialist soil can cost upwards of €/£/$ 50 per 50l bag and are said to contain sufficient nutrition for (almost) the entire grow.
The best soil mix for cannabis is often produced by blending several starting ingredients. The ingredients may include additives that are proven to be useful, such as bat guano, worm castings, dolomite limestone (contains Calcium & Magnesium), coco fibre, mycorrhizal bacteria as well as a high grade nutrient-rich soil/compost.
Many growers have found good results with peat based soils which don’t contain wood products. The absence of wood minimises potential problems later on with fungus gnats which thrive in a warm indoor grow room.
Lightmix is a blended soil type which is often used in the cannabis growing community. It contains a mixture of ingredients together with added perlite to make the medium more aerated. It also contains a small amount of nutrients, sufficient for the first weeks. Lightmix soil preparations are a good starting point for inexperienced growers.
The best soil for cannabis seeds and seedlings
Note that the best potting soil for cannabis seedlings and seeds is often a very light mix with low nutrient levels. Young cannabis plants and roots are easily burnt by soil which contains too many nutrients. The best soil for seedlings allows rapid root growth in the light, aerated soil. For young seedlings, nutrition is not as important as it is for mature plants in full bloom. In fact, a light mix with few nutrients is great for seeds and seedlings. Special soil types optimised for seedlings are available, such as Terra Seed Mix from Canna.
Photoperiod vs autoflowering cannabis soil
A good quality cannabis soil will give equally impressive results whether you are growing autoflower seeds or photoperiod feminised seeds. Don’t worry about making or purchasing different soil types. The cannabis roots have to absorb the same minerals and nutrients. There is simply no need to source different soils for your autoflower seeds and your feminised seeds. The best cannabis soils work well for both.
Best indoor vs outdoor soil for cannabis
Indoor cannabis growers are spoilt for choice when it comes to soil options. Many of the top brands do a great job. Some indoor growers are reluctant to change from their preferred soil choice once they feel settled with a particular soil recipe which works well for them. As well as trying to grow in the best soil for cannabis, indoor growers also try to fine-tune and improve their grow room conditions.
|How to grow cannabis indoors|
|Optimising your grow room conditions|
Many outdoor cannabis growers simply use the existing outdoor soil. Sometimes this can be supplemented with well-rotted manure and other additives. Experienced outdoor growers will test the soil with specialist test kits and amend the soil accordingly. If the outdoor soil is simply too low in nutrients/quality (e.g. too sandy) then it can be supplemented by high quality soil form the grow shop. Remember cannabis has been growing outdoors without human intervention for hundreds of thousands of years. Cannabis can grow well in many outdoor soil types.
Outdoor growers can grow their plants in the ground or in containers. When growing in containers avoid dark coloured/black containers which can get very hot in direct sunlight and ‘cook’ the root ball. This can slow growth rates or even kill the plant.
When growing cannabis outdoors in hot, dry regions some growers add water absorbing crystals to the soil. These are water retaining polymers (as used in babies nappies) which can greatly increase the water retention properties of your soil.
|Growing outdoor cannabis|
|Top 5 outdoor cannabis seeds|
Store-bought vs homemade cannabis soil
Many less experienced growers find it convenient to buy ready-made soil from their grow store. The more professional ‘living soil’ blends can be very expensive. That’s why some growers like to save some money and create their own soil blend themselves.
Note that there is not a single, definitive ‘best soil recipe for cannabis’. Cannabis grows well under a wide range of conditions and substrates. But if you want to know how to make your own soil for cannabis you may find the following recipe a good starting point. But remember you can vary the ratio of ingredients and even add your own supplements until you reach a blend that works well for you.
Basic cannabis soil recipe
Your choice of ingredients is quite wide. You can lighten the soil mix with coco coir, perlite, vermiculite or even sphagnum moss according to your preferences. Here is a suggested mix.
• 1 part coco fibre
• 1 part perlite
• 2 parts compost
• 1 cup of worm castings
Note. Other popular additives include small amounts of blood meal, dolomite lime, fish meal, bat guano, peat, bone meal etc. Mycorrhizal and other beneficial bacteria are also great at breaking down the soil and gradually releasing more nutrients. They are highly recommended to create a healthy ‘living’ soil.
Steps to follow:
• Sieve the compost to remove/break down any large lumps
• Place the sieved compost in a large mixing bucket and add the other ingredients
• Using your hands, ensure that all the ingredients are thoroughly mixed together.
Remember you can modify your recipe as you gain experience. But not everyone has the time to manually prepare and fine-tune their soil mixtures. For some people it’s easier to buy a proven brand of soil mix from the grow shop. For some growers the best cannabis soils are simply the easiest grow medium in which to produce the finest tasting organic cannabis.