What Soil is Best for Growing Indoor Cannabis Plants

indoor marijuana soil

Choosing the best soil mix for cannabis indoor is important. It’s one thing that will help you ensure the health of your plants and their yield.

What’s the Best Soil Mix for Cannabis Indoor?

Organic super soil is the best soil to use when growing marijuana indoors. Super soil provides the correct balance of nitrogen, carbon, phosphorus, and other essential nutrients to make sure your plants get exactly what they need while growing.

You can get either make or buy super soil online. Buying it is a good idea, especially if you don’t have enough space outdoors for setting up a compost heap.

Super Soil – What Is It?

Super soil is the term created by Subcool, a famous cannabis grower and seed producer. He coined the term “super soil” to describe his soil recipe. His goal is to make things easier and help people attain the best harvest, regardless of your expertise in growing marijuana. This organic soil is an excellent growing medium in which you don’t need liquid nutrients.

Why Choose Super Soil?

The concept behind super soil is you don’t need to adjust the pH or nutrient levels if you create a perfectly balanced and healthy growing medium for weed. All you need to do is water. Since super soil forms a hot or nutrient-rich soil, you must be careful when using it. Keep in mind that super soil is a concentrate used aside from base potting soil.

What are the Pros and Cons of Using Super Soil?

There are pros and cons of using super soil. Before you dive in, here are a few things to consider when using a highly modified soil recipe:


  • Natural growing method
  • Saves you cash on fertilizers
  • Saves you time on pH changes
  • It is nutrient-dense, so it can grow strong weeds
  • It mimics the natural external growing environment
  • You don’t have to flush your plants


  • Cooking time may be inconvenient and long
  • It may burn the plants when used incorrectly
  • It is not simple to manipulate
  • Yields are not as huge as with artificial nutrients
  • The growth cycle is a bit longer than with the liquid nutrients

How to Modify Organic Soil

Modifying organic soil is simple. You just need a few ingredients, like:

  • A natural base material like peat moss and coco coir
  • Compost
  • Any aerating agents like vermiculite and perlite

How to Buy Super Soil for Your Marijuana Plants?

MarijuanaBreak suggests some important things to remember if you want to buy super soil. First, buying soil in bulk can be a big mistake because there are no standards or certifications associated with soil quality. In fact, a few of these sellers will give you soil from the construction sites or excavated basements. When you buy soil for cannabis, make sure that you know the basics of healthy marijuana soil. If you want more trichomes and cannabinoids from your plants, then pay attention to different variables like:

  • Texture
  • Drainage
  • Water retention
  • Nutrients
  • pH level

Texture, Drainage, and Water Retention

In finding the best pot soil for cultivating cannabis, its drainage ability, texture, and ability to hold and retain water are the crucial factors to consider. Your marijuana plants cannot produce good yields if there is no perfect mix of oxygen and water within the roots.

If there’s much water, the oxygen supply for roots will be insufficient. If water is not enough, the roots will dry out fast and become damaged. High-quality marijuana must have:

  • Loose texture
  • A dark and rich color
  • Excellent drainage. In short, there should be no water pool on top. The soil must absorb the water fast.
  • The ability to hold water without turning to muddy.

It’s unlikely that your marijuana soil will gain the right texture, drainage, water retention abilities. Luckily, there are several amendments which can change soil’s texture, drainage, and water-retaining ability:

  • Coco Coir – coco coir comes from the coconut husks. It manages to enhance water retention without making the soil heavy. When using coco coir, the roots must develop faster which may help prevent overwatering. You can grow cannabis in pure coco coir, yet a maximum of thirty percent is the right one to achieve a productive soil modification.
  • Vermiculite – it improves water retention which can lighten the soil. For best results, use it with perlite.
  • Perlite – it is perhaps the most commonly bought amendment for cannabis soil because it is ideal for most soil mixes. Perlite consists of airy rocks that became popular due to their white color and popcorn-like form. Perlite is effective in improving drainage while increasing the oxygen supply. You can use 10 up to 20 percent to enhance water retention. You may go as high as 40 percent, but the nutrients may leach faster. When you use Vermiculite and Perlite, make sure these two will be 50 percent or less.
  • Worm Castings – this is all about worm poo. They may be disgusting, but marijuana plants love them more. Worm poo improves the soil’s ability to retain water. It can also enhance the soil’s texture and drainage. Their natural nutrients break down fast. They often have good microorganisms as they go through the digestive tracts of worms. But make sure you use worm castings the right way. Always keep it down to approximately 30%.


When you choose properly, your marijuana soil must have a big range of essential nutrients because it contains organic materials. One simple mistake that every cannabis grower can make is to try adding organic materials like animal manure and rotten veggies straight to marijuana plants as fertilizers. You should break down the materials first to help the roots absorb the existing nutrients.

Every indoor cannabis grower should look for soil containing more nutrients because they do not benefit from nature in a similar way with outdoor growers.

You can use heat in sterilizing the soil and add some nutrient-rich potting soil mixture. Make it yourself, but novice growers must buy it from a reputable garden shop. Water the super soil correctly and keep it inside a room under 68 degrees Fahrenheit. Test the pH level of the water as often as possible.


The acronym pH stands for the “potential of hydrogen.” It’s the chemical scale used in determining the acidity or alkalinity of a substance. The scale goes from 0 to 14. The pH level of 7.0 is neutral. If the pH level is from 0 to 6.9, the substance is acidic. If the pH level is from 7.1 to 14, it is alkaline.

The pH levels of hydrochloric acid and battery acid are both 0 while it’s 14 for fluid drain clearing liquid. Cannabis oil must be a little acidic. Many cannabis experts say that the best pH level for cannabis soil is 6.0. But when the pH level sits between 5.8 and 6.3, that means you’re on solid ground.

Your crop survives outside this range, but yields are much smaller. Obviously, when the pH level stays far from the 5.8 to 6.3 range, your marijuana plants will struggle to survive.

Buy Your Super Soil from a Reputable Store

If you choose to buy super soil instead of making your own, then make sure your preferred store is reliable. Super soil comes in different brands. It is also available in many stores online and offline. Make sure your super soil is of the best quality to make your goals much more attainable.

Do your homework before ordering. Look for a licensed store that offers a wide variety of soil brands. At the same time, you should look for your best choices when it comes to super soil brands. Some brands contain a range of amendments while others don’t. To get the best value for your money, do your best in finding the best soil mix for cannabis indoor.

Steps to Follow in Making Your Own Super Soil

In making your own super soil, you should control some things such as the temperature, carbon and nitrogen ratio, and airflow. Here are the steps to follow in making super soil:

  • Mark out one 3 x 3 square in the area.
  • Put down a 4-inch layer of any carbon material such as straw or dry leaves. This carbon material should cover the 3 x 3 square.
  • Add a 4-inch coat of nitrogen material such as coffee grounds or livestock manure.
  • Top it with a ½ inch sheet of bone meal or blood.
  • Repeat the first 3 steps. It must be layer by layer until the pile is 3 feet tall.
  • Allow the heap to decompose.
  • Turn the heap once every week. Do it not more than every 3 days.
  • The composting process will be complete when the soil is crumbly, soft, black, dark, and smells sweet.

You can use the super soil in planting your new marijuana seeds and in mixing 420 fertilizer.


Buying the best soil mix for indoor cannabis can be daunting. But making the best buying decision is easy when you know what to consider. The tips and hints provided above should help you get the best super soil for your needs.

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