Growing giant, nutrient-rich buds all starts with the soil. But, knowing what type of soil is best and how to prevent soil-borne diseases can be a bit tricky. To help you out, we’ve created this handy guide to making super soil for optimized growing. The tips and recipes here are organic and minimize the nutrient additives you’ll need throughout the growing cycle. Here’s everything you need to know about super soil.
1. Soil vs. hydroponic
To kick us off here is a brief breakdown of how soil methods compare to hydroponic methods. While both growing styles are effective, there are a few key differences between the two.
A lot of growers prefer hydroponic systems because of their reliability and speed. Hydroponic setups are soil-less systems. Once you get a good care and nutrient rhythm set up, you can count on high yields and sizable buds. However, no matter what is added to your hydroponic solution, it’s never going to be the same as what nature provides in the soil.
Cannabis grown hydroponically tends to be less tasty and may have lower levels of phytonutrients than soil-grown plants. You’ll supply most of the main vitamins and minerals through suped-up nutrient solutions.
However, unless you supplement with compost teas or pro-microbial solutions like Recharge, you’ll miss out on some of the phytochemicals the plant creates.
- Saves water
- More discrete
- Gives you ultimate control over the growing environment
- Fast, stable yields
- We can never fully replace nature (hydroponics lose out on the soil microbiome)
- You have to pay close attention to supply your plant with everything that it needs
With soil, you’re letting nature do a lot of the work for you. Once you get into a good stride with hydroponics, you can quickly get nice yields and a stable crop. However, growing in soil is going to give you a more nutritious and tasty bud. Working with soil gives your plant access to the extremely important soil microbiome.
The soil microbiome is a network of over 100,000 different species of bacteria, fungi, and other simple organisms. Plants actually communicate directly with organisms in the soil to create the nutrients it needs to build terpenes and cannabinoids. Working with soil gives your plant access to these microorganisms, allowing your plant to make more beneficial chemicals.
- Closer to nature
- High levels of nutrients and terpenes
- Organic and you add more topsoil back to the earth if you compost your leftovers
- Level of uncertainty, you face potential pathogens and soil-borne diseases
- Risk of lower yields with poor quality soil
- Takes longer
Detailed explanations of the pros and cons are in our article here.
2. How to make super soil for cannabis
To grow really great buds, you need to start with a nutrient-dense soil. For best results, pick out a high-quality soil mix like Royal Gold, Roots Organic, or FoxFarm ocean grown. To supplement the soil, you can add in a fertilizing mix like the recipe shown below.
This recipe is not for seedlings, as it will burn the roots. For seedlings, you need to use a light-weight soil with fine and fluffy granules. You can also use Rockwool or coco fiber. Make sure to check out our full article (link below) for information on how to use this recipe correctly.
Make sure to check out our full article (link below) for information on how to use this recipe correctly.
Organic soil recipe
The soil recipe below is adapted from SubCool’s recipe originally posted by HighTimes. This recipe was chosen because it is a popular, tried-and-true method that gives great results. Using this organic soil mix eliminates the need to add nutrients throughout the growth cycle.
Base: 8 X 30lbs bags of quality potting soil.
- Worm castings (25 to 50lbs)
- Humic acid (2 tbs) and/or Kelp powder (1/4 cup per every 5lbs)
- Bat guano (5 lbs)
- Rock phosphate (3lbs or 10lbs per every 100 square feet of soil)
- Bone meal (5lbs)
- Blood meal (5lbs)
- Dolomite (1 cup)
- Azomite (1/2 cup)
- Epsom salt (1/4 cup)
For details on what these ingredients are and what they do for the plant, please visit our full article here.
3. Creating healthy soil microbiology
The health of your plants is a direct reflection of the health of your soil. Healthy soil contains microbes. As mentioned earlier, there are over 100,000 species of simple organisms that live in soil. These organisms help your plant create compounds like THC and tasty terpenes. In a way, each little bacteria acts as a little sack of nutrient fertilizer for your plant.
Believe it or not, your plants actually send signals out through their roots to attract certain microorganisms. These signals are called exudates, and they’re little sugars that bacteria like to eat. When your plant needs a certain mineral, it sends out specific exudates to attract bacteria that will provide what it needs.
In soil, plants have access to a wide variety of trace minerals and chemical compounds that we’re really only beginning to understand. Soil Doctor Elaine Ingham explains this process best,
We can’t even begin to put a name to almost all of the bacteria and fungi that are down in the soils. We can’t grow them on any laboratory medium. We don’t know exactly what they do.
So, if you don’t know what species of bacteria or fungi are actually doing, really our approach to dealing with this system is that we need to maximize all of the diversity that we can possibly get in there, and let your plant start choosing those organisms that will do the work for them. – Dr. Ingham
Some growers recommend sterilizing your soil before planting. This takes away from microbial diversity. Starting with high-quality soil and reputable compost means that you get to keep the diversity, giving your plant access to the beneficial organisms it has adapted to interact with over millions of years.
So, how do you create healthy soil microbiology? Here are a few quick tips.
Let your soil breathe
The thought of bacteria and fungus spreads fear in many growers. Microorganisms are often thought of as bad or undesirable pathogens. This is true for some microbes, but neither humans nor plants can live without microorganisms.
To encourage beneficial microorganism growth, your soil needs plenty of oxygen. These are a few ways to make sure your soil has enough air:
- Opt for breathable containers like Smart Pots. Typically, 5-gallon containers are the best
- Make sure your container has proper drainage
- Add perlite or vermiculite to your potting soil
- If you’re in a raised bed or outside, add worms. Worms are natural aerators
- Avoid overwatering. Overwatering encourages the growth of bad organisms that can live without oxygen
- Aerate your water using an aquarium pump
No matter what soil base you’re using, plants love compost teas. Compost teas are a form of vegan and organic fertilizer that works by providing your plants with healthy nutrient-producing microbes rather than applying concentrated nutrients directly.
You can make compost teas out of high-quality, properly processed compost or nitrogen-rich worm castings. Worm casting tea might be better for the vegetative state.
Note: the video above uses fish fertilizer in their tea recipe. This is not necessary if you’re interested in veganic cannabis.
Another way to improve microbial diversity in your soil is to simply feed the microbes. Common chemical nutrients and salt-containing products can actually kill beneficial microbes in the soil. To encourage healthy microbes to grow, there are a couple of things they like to eat.
Just make sure you’re not applying foods in soil that has poor oxygen circulation, that will lead to an unhealthy soil microbiology.
- Beneficial bacteria: sugars and carbohydrates, like blackstrap molasses
- Beneficial fungi: humic acid and kelp powder
For tips on how to avoid common soil-borne pathogens like fusarium, click here.
There’s a lot more to soil microbes. To learn more, visit our full article here.
4. Managing pH
Finally, in order for your plant to properly absorb nutrients in soil you’ll need to make sure the soil is kept at the right pH. Cannabis plants like soil that is slightly acidic. Ideally, you want your pH to hover at right about a 6. Though, the herb can tolerate a pH between 5.8 and 6.5.
Keeping your soil at the right pH is essential for optimal growth. If your plant isn’t absorbing nutrients properly, you’re wasting all of those fancy organic products and fertilizers you keep applying. For best results, test your soil pH frequently using an electronic pH meter or some color strips.
You should also test the pH of the products you’re applying to your soil to make sure they don’t alter the overall pH of the growing medium.
If you need to adjust your pH, you can use products like General Hydroponics’ pH Up and pH down. Watering with aerated water that has the correct pH will also help restore the right balance to your soil.
For more information on how to adjust pH, read our full article here.
Growing in soil is the method nature intended, but the process is more complicated than you might think. This simple introduction gives you a brief glimpse into how to cultivate a healthy soil for cannabis plants. As mentioned before, your plants are only as good as their growing medium.
If you want healthy, nutritious, big buds, you have to start by cultivating a nutrient-dense super soil.
Do you have any super soil growing tips? Share them with us on social media or in the comments below. We’d love to hear from you!