Additives that will help you improve soil quality, resulting in better growth cannabis. What to consider when it comes to growing weed in organic soil. If you have an indoor cannabis grow set-up, you need the best soil for growing weed indoors. Our guide dives into what factors to consider and the best ones.
Best Soil For Cannabis – What is Good Soil For Growing Weed?
Signs of good and bad soil quality, other additives that help to improve soil quality and what to consider when it comes to planting this year.
- 1. The benefits of organic soil
- 1. a. Organic soil additives
- 2. Other additives that improve soil quality
- 2. a. Coco
- 2. b. Biochar
- 2. c. Perlite
- 2. d. Vermiculite
- 3. Signs of good soil
- 4. Signs of bad soil
- 5. How to make your own soil
- 5. a. Best nutrients for soil
- 5. b. Cheap mix for diy soil
- 5. c. Best soil for beginners
- 5. d. Ph too high or ph too low
- 5. e. Best soil for marijuana
- 6. In conclusion
When growing autoflowering Cannabis plants, it is very important to keep them supplied with nutrients in the form of hard foods, or liquid feeds. The best soil for autoflowers will depend on your environment, fertilizers, and ability to control the pH, so keep this in mind if this is your first grow cycle, knowing the best option in your case can really set you on your way to bountiful harvests.
So if you’re wondering what soil is best for growing weed, below we’ll explain what to know, the signs of good and bad soil quality, as well as what you should consider when it comes to planting this year.
1. The Benefits of Organic Soil
Soil for autoflowers or for any other type of cannabis plant consists of organic material that is in a permanent state of decomposition. Teaming with beneficial microorganisms that are responsible for converting nutrients to the plant’s roots, living soil is Mother Nature’s way of allowing autoflowering plants to work in a symbiotic relationship. As the tiny microorganisms decomposing the organic matter, they make the nutrients available for the roots, which are now able to access all the available nutrients and minerals found within the soil web. Once this symbiosis occurs, then the only real requirement is for the soil to be adequately watered. This is basically the most simple form of organic growing that is perfect for those new to growing, it requires very little maintenance, and labor, as well as allowing the grower to work with a slow buffering organic process, so if you were wondering what is the best soil for growing weed, read along.
Organic Soil Additives
Using organic soil additives or amendments will help increase the number of beneficial microorganisms, improve moisture retention, and help you control the health of your soil. In general, you should be looking at adding these amendments before planting. They will help you create the best organic environment for the root system to thrive, which will result in amazing growth and the full terpene profile maturing.
Bat guano is one of the most widely used additives in cannabis cultivation. It is a fast-acting, highly bio-available organic fertilizer with high rates of nitrogen and phosphorus making it perfect for the vegetative growth stage. It also helps improve the drainage and oxygenation of the soil mix, helps boost the natural immunity against pests, fungal infestations, and disease, and can ensure the best possible terpene production (although there is little scientific evidence to back up this claim).
Be careful with the amount you introduce to the substrate, as bat guano is pretty strong stuff. A little goes a very long way.
It can be used in both its fresh or dry form and is typically sourced in either powder or pellet form. It can be used in many ways other than as a direct additive to the soil. Many cultivators used bat guano as a fertilizing tea, or as a foliar spray. It can also be used as a top dressing by sprinkling it directly around the base of the plant and then watered in. To make a super effective bat guano tea all you need is 15 grams of bat guano, 1 liter of lukewarm water, and an air pump. Mix the guano and the water together well, and make sure the water is only lukewarm. Hot water will kill the microbial life that you are trying to introduce to the mix. Give it all a good mix, throw the pump in and let it aerate for at least 24 hours. This tea can be supplied twice a week throughout the entire lifecycle of the crop.
Worm casting, or worm poo, is literally the most bio-available organic fertilizer with ridiculous levels of both nutrients and minerals. Also referred to as vermicast, this top-shelf additive is perfect for any organic cannabis garden. It not only provides long-lasting, slow-release nutrition to the crop but also increases the aeration of the soil and provides excellent drainage.
You can swap out any potting mix you may use for 100% worm castings, and you do not have to worry about nutrient burn issues at all. Creating your own worm farm at home is super simple and can provide you with an unlimited supply of castings, ready to use at a moments notice, and provide your crop with almost everything it needs to provide you with bumper harvests.
Cow manure makes a perfect slow-release fertilizer. It usually contains a very well-balanced mix of the three main macronutrients that plants need for healthy and vigorous growth, plus manure works as a very efficient soil conditioner and helps increase the amount of microbial life in the soil, while also boosting moisture retention. Keep in mind that some manures may have herbicide contamination, so always check the packaging to ensure it is fully organic. If you live near a farm and can get it directly from the source then even better!
You want to mix the manure in before planting, and make sure there is no heavy rain forecast for the next week or so to prevent the chances of all the goodness being washed away. Chicken manure, on the other hand, is considered to be “hot” manure, meaning it can easily burn the plants if not allowed to sit and mature. In general, we do not recommend using chicken manure for your cannabis crop.
Bone Meal and Blood Meal
Bone meal is made from the ground-up bones of beef cattle and is a fantastic source of both phosphorus and calcium. It is used pretty extensively with outdoor cannabis cultivation but is not recommended for indoor growers. It does come with quite an acidic pH level which needs to be balanced, so keep that in mind. Blood meal is made from, you guessed it, the blood of beef cattle. It is very rich in bio-available nitrogen, but can also easily burn the plants if overused.
It too comes with quite an acidic pH level which must be balanced. Both of these additives can attract the attention of wild animals which can easily wreck the crop, so make sure any plants that use these amendments are well fenced off. It goes without saying that these additives are anything but vegan, so if that is important for you then choose other fertilizing options.
Kelp meal is one of the most desirable additives for cannabis crops, as it is packed full of over 65 different essential elements and minerals, and also contains a very healthy dose of potassium. Many growers are of the thinking that kelp meal provides a huge boost to the flavor and color range of cannabis, which we agree with.
Every single cannabis crop, no matter the method or techniques applied, should have mycorrhizal fungi added. This type of fungi plays a very important role in helping the plant feed on the nutrients by turning them into a more bio-available source. They also help protect the root system from attack by pests, disease, and harmful fungi.
2. Other Additives That Improve Soil Quality
One of the downsides to using soil found in the ground is that it can be very dense once watered. Restricting root growth during the early stages of a Cannabis plant’s life is never advised, so adding other substrates into your living soil can be very advantageous.
By simply adding a 25-50% ratio of coco coir to your cannabis soil, the quality of the mix will become very airy and lightweight. Adding coco will enhance the air pockets present, the wicking action of the medium, as well as encourage a mass expansion in the rhizosphere. Coco is very user-friendly and is well associated with large yields. The best thing about adding coco is the fact it is an inert growing medium, so does not have any nutritional value in terms of Nitrogen, Phosphorus, or Potassium, including trace elements.
- Increases aeration and holds water better: Due to its characteristics, coco fiber can increase aeration in the soil and can absorb up to 10x its own weight in water, making it vital for growers living in dry weather.
- Cheap: Coco fiber is relatively cheap and comes in various forms. You can find it compressed into a brick or already washed and ready to use out the bag, the price may change a bit depending on your preference but it won’t be absurdly expensive.
- Easy to use: Coco is a sterile medium so fungus and other bugs avoid it, making it perfect for growing cannabis. Also, because of its neutral pH, you can use it with soil amendments without worrying.
- Sterile: Because this type of medium is sterile, it won’t contain any of the nutrients your plant needs, even though you can mix it with soil or even amend it, you will have to provide all the nutrients your plant needs if you’re only using coco.
- Needs to be washed: The quality can vary from brand to brand, so depending on the brand, you will have to soak it and wash it a couple of times to remove impurities before using it.
- Hard to find good quality: Even though it’s relatively easy to find coco coir, it can be hard to find good quality coco fiber. This doesn’t mean you can’t use it but you will have to wash it thoroughly and experiment with a couple of brands before you’re 100% satisfied.
An incredible organic addictive that has amazing water-holding capabilities, an enormous surface area, and is a source of pure carbon. Biochar is made by heating wood to such temperatures that the end result is a tiny, charcoal-black crystalline substrate. Due to the fact it is 100% carbon and has a shelf life of thousands of years, organic farmers use biochar with their soil to improve water retention allowing for less watering times, feeding the beneficial microorganisms a rich source of carbon, and helping save the planet.
Organic additives like Coco Coir and Biochar can drastically improve the quality of your soil, improve water retention and not to mention help you to save the planet.
- Increases soil fertility: Biochar can boost soil fertility when used in combination with amended soil because it prevents nutrients from leaking out and provides carbon which increases the availability of nutrients in the medium.
- Holds nutrients and moisture: Thanks to its porous surface, biochar can absorb a lot of water and draws in minerals which are essential for plant development.
- Reduces the need for fertilizers: Because biochar is carbon-rich, it accelerates the decomposition of organic matter which results in more nutrients being available in the medium, a perfect choice for organic growers.
- Can affect yields: Due to the porous characteristic, biochar can absorb too much water and nutrients when used in excess and can end up stressing your autoflowering plants which will show signs of deficiencies.
- Can be contaminated: The quality of biochar is influenced by the material it is made of, so it can come contaminated with heavy metals or harmful compounds that are bad for your autoflowering plants.
- Harmful to humans: If not dealt with caution, you can end up breathing ash which is a concern if exposed to daily, also, it can irritate you if it comes in contact with your eyes or skin for a long period of time.
Perlite is usually used in soil mixes to increase aeration and improve the soil’s texture, by using perlite in the proper amounts you will not only improve drainage but also avoid compaction, making it a better medium for the roots to grow in. Usually, perlite is used in combination with coco fiber and soil to provide the best medium for the roots, while perlite improves aeration, coco fiber absorbs water, balancing those two elements in the best ratio possible.
Perlite can also be used to plant clones in, when you place your cuttings in perlite, the roots usually grow stronger and faster because they need oxygen to thrive and perlite helps provide it.
- Increased aeration: Perlite creates small air pockets in the soil so if used properly, it can improve the growth rate.
- Sterile medium: Because it’s a sterile medium, perlite won’t affect the pH of your medium or increase the amount of minerals in it.
- Avoids soil compaction: Perlite needs to be thoroughly mixed in the soil before using, this will create several air pockets that make the soil fluffier, avoiding compaction.
- Can dry the medium faster: You will need to check your autoflowering plants closely because with more oxygen in the soil you will have to water more often.
- Needs to be washed first: If the brand you’re using does not pre-wash the perlite, it may come with a fine dust that can be harmful if inhaled so we recommend washing your perlite before using.
- Needs to be watered more often: Because the medium will dry faster, you will need to water more and this means you will need to check on your autoflowering plants at least 2 times per day to make sure everything goes accordingly.
Vermiculite can be used to improve the quality of your soil, just like perlite, vermiculite has several qualities that will make your autoflowering plants grow better and faster. This mineral helps aerate the soil, holds water and nutrients while not being toxic or changing the pH.
If your soil is compact or does not drain water properly, you can add vermiculite to provide the roots a better medium to grow in, just make sure you’re using the proper ratio because too much can hold a lot of nutrients and water and end up harming your autoflowering plants.
- Neutral pH: Because it’s a sterile medium, vermiculite will not alter your soil’s pH so there’s no need to worry about checking the runoff every day.
- Can prevent mold: When used in the proper ratio, vermiculite will absorb the excess water, preventing mold and fungus in the soil.
- Improves soil quality: Just like perlite, vermiculite improves the soil’s texture and makes it fluffier, preventing soil compaction.
- Can be expensive: Depending on where you live, vermiculite can be relatively hard to find and a bit expensive because it’s not usually found in regular grow shops.
- Can affect autoflowering plants if used in excess: Because perlite holds nutrients and water, using it in excess can ultimately result in overwatering and overfeeding.
- It’s said to be harmful: When buying low-quality vermiculite, it can contain asbestos and can cause lung problems. Inhaling these tiny fibers can cause asbestosis, mesothelioma, and lung cancer if exposed for a long time so it’s essential to buy the best quality possible and wash it before using it.
3. Signs of Good Soil
Due to the process in which soil is naturally produced, there are a few factors to consider if you are going to prepare your own. If buying soil from a well-known brand, or your local garden center’s cheap and cheerful products then there are some things to consider.
- Check the packaging to see the nutritional value of the soil. A good brand will take the time to display a soil nutrient analysis displaying-N-P-K values, amount of perlite, vermiculite, compost, trace elements, and the bacterial and fungi count present.
- Worms aerate the soil as they crawl through eating up organic matter. If you see your soil full of worms then do not worry. Not only will these little helpers aerate the soil but will release beneficial bacteria from their gut as they do.
- Good store-bought soil will have perlite or coco added allowing for the ideal balance of air to water retention. Avoid soils that do not have any perlite unless you are purposely buying pure worm castings.
4. Signs of Bad Soil
- Bad soil will have an unpleasant smell which is a red flag bad bacteria are present, causing the medium to be in an unfavorable acidic state.
- Drainage will be poor, causing the soil to become dense and heavy. This weight can restrict root growth and slow plant development down dramatically. The ratio of water retention, drainage, and wicking capabilities will all be out of balance.
5. How to make your own soil
To make your own soil mix you need to have in mind the conditions that you will have during your growing cycle, things like temperature and humidity may have an influence in the best mix, so make sure you know the conditions before mixing your soil.
Best nutrients for soil
We recommend always using organic nutrients when growing in soil because soil it’s organic matter and contains microorganisms that can greatly benefit your autoflowering plants if taken care of properly. We cannot recommend a certain brand or organic nutrients line but as long as you’re using high-quality organic nutrients and use them appropriately, you’ll be fine. Just make sure the nutrients are 100% organic and keep an eye on the pH level because a drastic increase or decrease can ultimately kill the microorganisms present in your soil.
Benefits of good quality soil and what to keep in mind when you’re looking for the best soil for cannabis possible.
Cheap mix for DIY soil
Even though you can find organic nutrients in your local grow shops, they can be quite expensive so if you’re on a budget there are good alternatives that are relatively cheap.
There are several other methods to make your own organic nutrients such as KNF and Bokashi.
Depending on the space you have available, you can try composting or vermicomposting, these methods allow you to make your own tailored organic soil that will provide everything you need without spending too much.
Best soil for beginners
If you’re a beginner grower and don’t know exactly how things work, here is a general soil recipe that will work fantastically in almost all types of weathers, just remember that as time passes and you get more experienced, it’s ideal you adjust it to your specific needs.
General DIY soil recipe mix:
- 80% organic soil
- 10% perlite
- 10% coco fiber
Remember that you can and should tweak it to your needs, but as long as you maintain a similar ratio your autoflowering plants will grow exceptionally.
PH too high or pH too low
If the pH of your medium is too high or too low, you should check the nutrient solution you’re feeding, have in mind that most additives are sterile and neutral so if you’re experiencing pH problems you should check the water source and nutrient solution.
Best soil for marijuana
The best soil mix for autoflowers or best marijuana soil, in general, will depend on the weather you have throughout your grow cycle, by following the table you can easily choose the one that better suits you.
|Advantages of soil additives when growing autoflowering plants|
|Additive||When to use||Advantages|
|Coco fiber||Use in dry environments or to improve soil quality.||Holds water and helps avoid soil compaction.|
|Biochar||Use in dry climates or when growing in organic soil.||Improve water retention and helps decompose nutrients faster.|
|Perlite||Used to help aerate the soil in humid environments.||Helps dry the soil faster and increases aeration.|
|Vermiculite||Used in dry environments, helps keep the soil moist.||Improves soil quality and helps keep it moist.|
As a general rule, you should always use 70-80% of organic soil mixed with the additive of your choice, always have in mind to use additives with different properties, for example, vermiculite shouldn’t be used with coco fiber because both absorb a lot of water and can cause overwatering.
- 70% organic soil
- 15% perlite
- 15% coco fiber or 15% biochar or 15% vermiculite
For the best soil for autoflower plants, we recommend using 70-80% organic soil mixed with 15% perlite and 15% coco fiber, or substituting coco for vermiculite or biochar, always respecting their properties to avoid having oxygen or water in excess. Remember that for the best growing medium for autoflowers, you should be on the lookout for the tips your plants give you and adjust the ratio if needed.
6. In conclusion
There isn’t a best soil for weed, in general, having all of the nutrients covered is one-half of a top-quality soil for marijuana, however, it should also have the ideal ratio of drainage, air pockets, and wicking action so we recommend looking into super soil for autoflowers.
Once you have found the ultimate balance, you can now confidently re-use your organic growing medium for multiple crops with the understanding the more time the living soil food web has to develop, the greater the results in terms of plant performance and yields.
Best Soil For Growing Weed Indoors
If you have an indoor cannabis grow set-up, you need the best soil for growing weed indoors. Our cannabis soil guide dives deep into the factors to consider when shopping for soil for pot plants including its drainage, water retention, and texture.
In addition, we list our favorite potting soil products for cannabis, so you can grow big and bountiful yields time after time.
Choosing the Best Soil for Indoor Cannabis Gardens
When shopping for the best potting soil for cannabis, there are few factors to consider. First, how many plants are you intending to grow? This will help determine the amount of soil you will need.
Above all, you want soil with plenty of nutrients, proper drainage, and good water retention. Here are some factors to consider when buying the best potting soil for weed.
The best soil for growing weed indoors includes an optimum mixture of silt, sand, and clay soil, known as loamy soil. Ideally, the mix should have about 40% silt, 20% sand, and 40% clay.
Make sure your plants get a loose and light soil texture to help with root growth and ensure oxygen gets to your roots.
Cannabis potting soil requires proper soil drainage. When watered, the soil should not hold the water too much to where it pools on the top. If you have bad drainage, your plants can be vulnerable to root rot and mold.
While you want soil with proper drainage, you also don’t want the water to completely flush through without allowing the roots to take in water and nutrients.
Water retention refers to your soils ability to hold water. The best soil for growing pot indoors has balanced drainage and water retention properties.
PH refers to how alkaline or acidic solution is. Cannabis thrives in a soil pH range between 5.5 and 6.5. Deviating slightly from this range won’t cause too much damage but if it goes well beyond the range, you can get stunted growth, lower yields, and dead plants.
Nutrients are your cannabis plants life force. Most ready-to-use and organic soil mix for weed is packed with nutrients for your cannabis.
Keep in mind, the nutrients in your soil mix don’t last forever. At most, they can last a few weeks and require you to keep a close eye on any nutritional deficiencies or signs of overfeeding.
Best Soil for Growing Weed Indoors
1. FoxFarm Happy Frog Potting Soil
FoxFarm’s Happy Frog Potting Soil is ready-to-use for indoor and outdoor applications. Happy Frog potting soil features soil microbes such as mycorrhizae and humic acid to improve root growth and nutrient uptake.
Other goodies include bat guano, aged forest products, and earthworm castings. Keep in mind, this soil is designed for container planting.
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2. FoxFarm Ocean Forest Potting Soil
FoxFarm’s Ocean Forest Potting Soil features a robust blend of ingredients from the “earth and sea.” Its powerful ingredients include fish emulsion, aged forest products, earthworm castings, crab meal, and sphagnum peat moss.
Its sandy loam, aged forest products, and sphagnum peat moss give this soil a properly aerated texture that is sure to improve nutrient uptake. This soil is also designed for container use.
3. Super Soil Organic Concentrate
From Nature’s Living Soil, the Super Soil Original Organic Concentrate comes in a 1, 5, or 10 lb. bag. All you need to do is add your preferred organic potting media to complete your mix. It contains all organic ingredients that your plant will need to thrive.
Full of helpful microorganisms and fungi, this concentrate can produce the best-looking and tasting buds around. Ingredients include organic earthworm castings, bat guano, blood meal, bone meal, azomite, epsom salt, coconut water powder, kelp meal, alfalfa meal, and so much more.
4. FoxFarm Coco Loco Potting Mix
FoxFarm’s Bush Doctor Coco Loco is a coconut coir potting mix meant to recreate the tropical jungle floor. Light and airy, it does this by incorporating layers of exotic coconut palm humus which can hold more than its weight in water while still retaining great drainage characteristics.
Its ability to hold onto water will mean you wont need to water your garden as often. Water every few days for best results.
5. Big Rootz All-Purpose Potting Soil
Big Rootz’s All-Purpose Potting Soil features a professional-grade composition at a budget-friendly price. This cheap soil for growing weed is meant for indoors or outdoor gardens and has been Certified Green Clean (CGC).
A team of weed growers developed this high-quality formula that combines rapid-release amendments with medium and slow release for an optimal performance.
6. Roots Organics Rod Original Potting Soil
Roots Organics Original Potting Soil is ready-to-use for your indoor garden. Its formula is perfectly designed for aeration and water retention so you can feed your plants frequently for fast growth.
Plus, the soil bags can be used as pots. Simply cut off the top, add in your plant, and you’re set. Ingredients include coco fiber, perlite, peat moss, pumice, composted forest material, bat guano, worm castings, fish bone meal, and much more.
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