Exciting may not be the first adjective that comes to mind when you think about soil, but we’d like the opportunity to change your mind. Cannabis growers know that soil is as important as any other part of your operation. Soil can separate the men from the boys.

Get the image of a pre-mixed plastic bag from your local home improvement store out of your head. Yes, it’s an easy and economical way to get your grow started and for beginners, it’s a viable option. You can find organic super soils in stores if you look closely.

But making your own super soil is just as easy, just as economical, and will give you the feels in a way that that plastic bag just won’t. Along the way, you’ll also learn about soil science and how each component that you add to your soil will affect your cannabis plants. That makes you a better grower with a higher quality end product.

Getting exciting, right?

Why Is Soil Life Important?

The key to successfully making your own organic super soil is soil life. Good soil is full of living organisms. How much you ask? Well, a shot glass full of proper soil will have more living organisms in it than there are humans on this planet.

These organisms interact and serve a purpose that aids in soil life. Thanks to these organisms, the soil not only sustains itself, but is strong enough to provide nutrients to the plants that you put in it. When you get it right, you only need to add water. Toss those synthetic nutrients in the garbage.

Why Is Organic Important?

When you grow cannabis organically, you get a higher-quality product and you get it without chemical nutrients. These chemicals, while helpful, can also burn or even kill your plants. There are a lot of great recipes out there for organic super soil out there.

The most famous belonging to a guy known as Subcool. His recipe was the first and remains the best. But digging a little deeper to learn why it’s the best organic soil recipe out there will help you figure out what works best for your grow in your environment.

Know What Needs to Go In

What’s in soil to begin with? If you look on that plastic bag of pre-mix you’ll see the list of ingredients along with what nutrients it has. When you take soil from your back yard or other outside source, it doesn’t come with a list of ingredients. For that, you need to submit a sample for testing. This is much easier than it sounds and it gives you information about what base you’re starting with. After that, dig in and get your hands dirty. Working your hands through the soil will tell you a lot. Whether your soil is fluffy or compact, full of clay or sand, teeming with worms or insects, and how well it will hold moisture.

Select the Right Amendments

Once you’re familiar with the texture, physical qualities, and nutrient levels in your soil, you need to add in amendments to compensate for what’s missing. The foundation for growing plants is centered around N-P-K, or nitrogen (N), phosphorus (P), and potassium (K).

A strong soil that grows strong plants needs to have plenty of these three for your plants to absorb.

Nitrogen Rich Materials

  • Worm castings – you’ll get a quick release of nitrogen while simultaneously introducing healthy bacteria to the soil.
  • Crustacean meal – not as fast a release as worm castings, but you also get hefty doses of phosphorus, calcium, and chitin. The chitin loving microbes will keep nematodes from your plants
  • Bat guano – you’ll get the highest level of nitrogen and phosphorus from bat guano. It’s kind of a miracle worker when it comes to long term plant growth. It also diversifies your super soils microbes and other bacteria.

Phosphorus Rich Materials

  • Bone meal – taken primarily from cattle bones, it will keep phosphorus levels up. If your soil isn’t below a pH of 7, hold off on adding bone meal. A pH below 7 is when it will be most beneficial to add.
  • Chicken manure – another great amendment for both phosphorus and nitrogen. Get fully processed and high quality manure and be sure to add it in long before you introduce your plants.
  • Rock dust – this is a slow releasing source of phosphorus which will be effective for years. But just like bone meal, keep your soil below pH 7 for the most effectiveness.

Potassium Rich Material

  • Kelp meal – promotes microbial diversity. It’s water soluble so you can add it in to your water or by hand.
  • Wood ash – perfect for adding potassium, but be careful. It will also slowly raise your pH level. If you’re working with wood ash, be sure to test pH regularly.
  • Compost – look for compost that’s had time to age. Anything with banana peels and other fruit rinds is great for growing.

Don’t Forget Your Micronutrients

After N-P-K there are a number of micronutrients that you’ll need. Consider adding gypsum, kelp meal, or azomite to strengthen your soil with a variety of micronutrients. The more you have the more nuanced your end product will be in terms of aroma, flavor, and effect.


Once you’ve adding your selected amendments, start tilling. It does take time to make sure everything is adequately mixed. Add water when you’re done and repeat this process every 2-3 days. You know your soil is ready when you bury your hand in it and it’s cool to the touch.

Building your own soil is a good investment in your final product. It gives you insight into how cannabis grows and thrives. It can save money and, in the long run, time.