Top 5 Soils for Growing Cannabis Indoors – Updated for 2021

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If you want to grow good weed, you need good soil.

A lot of beginner growers make the mistake of buying their soil from a big box store like Wal-Mart or Home Depot.

This will kill your plants before they can even sprout from the seedling stage.

You need to use soil that’s specially formulated for growing marijuana. These are the 5 best choices based on my personal experience. I’ve had several harvests that were 16 oz+ so trust me when I say I know what I’m talking about.

I’ve used these soils and I know them inside and out. If you’re in a hurry, here are my top choices.

Fox Farm FX14047-2PK FOXFARM FX14047 pH Adjusted Happy Frog Organic Bags 2 CUFT, Brown Potting Soil
FoxFarm Ocean Forest Potting Soil Organic Mix Indoor Outdoor For Garden And Plants - Organic Plant Fertilizer - 38.5 Quart (1.5 cu ft). - (Bundled with Pearsons Protective Gloves) (1 Pack)
MOTHER EARTH Coco Plus Perlite Mix - For Indoor and Outdoor Container Gardens, Provides Strong Aeration & Drainage, 70% Coconut Coir, Resists Compaction, 50 Liter
Category
Best Overall
Best for Higher Yields
Best for Drainage
Name
Fox Farm Happy Frog
Fox Farm Ocean Forest
Mother Earth Coco & Perlite Mix
Rating
⭐⭐⭐⭐⭐
⭐⭐⭐⭐
⭐⭐⭐
Fox Farm FX14047-2PK FOXFARM FX14047 pH Adjusted Happy Frog Organic Bags 2 CUFT, Brown Potting Soil
Category
Best Overall
Name
Fox Farm Happy Frog
Rating
⭐⭐⭐⭐⭐
FoxFarm Ocean Forest Potting Soil Organic Mix Indoor Outdoor For Garden And Plants - Organic Plant Fertilizer - 38.5 Quart (1.5 cu ft). - (Bundled with Pearsons Protective Gloves) (1 Pack)
Category
Best for Higher Yields
Name
Fox Farm Ocean Forest
Rating
⭐⭐⭐⭐
MOTHER EARTH Coco Plus Perlite Mix - For Indoor and Outdoor Container Gardens, Provides Strong Aeration & Drainage, 70% Coconut Coir, Resists Compaction, 50 Liter
Category
Best for Drainage
Name
Mother Earth Coco & Perlite Mix
Rating
⭐⭐⭐

Last update on 2021-09-22 / Affiliate links / Images from Amazon Product Advertising API

Happy Frog Potting Soil by Fox Farms

Happy Frog is easily the best soil I’ve ever used.

The nutrient mix is just right and it does a good job of maintaining the right pH level. Fox Farms also has a good mix of microbes and fungi which help with nutrient uptake for your plants.

The addition of bat guano, earthworm castings, and other organic matter gives the soil a nice boost in helper nutrients that keep the plants healthy.

I’ve had issues with some other soils where my leaves start to turn colors due to nutrient deficiencies but I’ve never had these problems with Happy Frog.

It’s the best soil out there. Buy it. You won’t regret it. 

If you want to learn more, you can check out the full review of Happy Frog Potting Soil here.

  • Complete balanced nutrition
  • Perfectly maintains pH level
  • The right blend of microbes and fungi for maximum nutrient absorption
  • Contains bat guano, earthworm castings, and forest humus
  • Light texture
  • Perfect for container plants
  • No topsoil, no fillers and no sludge.

Last update on 2021-09-22 / Affiliate links / Images from Amazon Product Advertising API

Ocean Forest by Fox Farms

Fox Farms Ocean Forest, sometimes abbreviated as FFOF, is a good soil but can sometimes be a little too heavy on the nutrients.

Fox Farms loads this soil up with so many nutrients that it can actually cause nutrient burn which makes your plants leaves start to turn colors towards the tips because they’re getting too many chemicals.

BUT, this is good soil. I’ve had some of my best yields with this soil but it seems to depend on the strain.

Some strains are a little tougher and will use the extra nutrients to grow like crazy.

Other strains get nute-burn when they’re just a couple inches tall and it seems to stunt their growth.

I’d recommend giving Ocean Forest a try but if you see any signs of nutrient burn, switch to Happy Frog which is a more gentle blend. FFOF also lasts a pretty long time so don’t worry if you buy too much.

  • Lightweight
  • Well-aerated
  • All-natural
  • pH allows for optimum fertilizer uptake
  • Contains worm castings, guano, and aged forest products

Last update on 2021-09-22 / Affiliate links / Images from Amazon Product Advertising API

Mother Earth Coco + Perlite

My first two choices were soil based…soils. Basically, they’re made of dirt.

This “soil” is actually a blend of coco and perlite which means it’s not soil at all.

The reason some people prefer coco and perlite is that it offers really good drainage. 

A lot of newbie growers struggle with over-watering their plants and stunting their growth. By using coco and perlite, you’ll be guaranteed to not over water.

The downside of using coco is that it doesn’t provide nutrients so you need to get your plants nutrients by using a fertilizer like Fox Farms Trio.

  • 100% natural coconut coir
  • No artificial additives
  • Great aeration and drainage
  • High cation exchange capacity

Last update on 2021-09-22 / Affiliate links / Images from Amazon Product Advertising API

Big Rootz All Purpose Potting Soil

Big Root All Purpose Potting Soil is a good soil if you’re looking for an alternative to Fox Farms, but to be honest it’s pretty expensive to buy online.

If you can find this in a store, give it a shot. It’s a nice soil mixture and grows good buds.

  • Versatile for indoor or outdoors
  • Use as an additive to boost existing soil
  • Includes triple washed coir, peat, worm castings, compost and mycorrhizae
  • Completely organic

Last update on 2021-09-22 / Affiliate links / Images from Amazon Product Advertising API

Roots Organics Rod Original Potting Soil

With perfect consistency that enables proper drainage for an active root system, this soil comes ready to use.

  • Contains extra-long coco fibers, premium earthworm castings, bat guano, fish bone meal, feather meal, glacial rock dust, mycorrhizae, soybean meal, humic acid, pumice, perlite, and green sand
  • Excellent drainage
  • Better yields and healthy plants
  • Ready to use

Get it here.

Buying Guide

If you’re really interested in learning about cannabis soil and you want to understand why the soils I chose work so well, here are some of the factors that go into the quality of the soil.

The biggest factors are the nutrients in the soil and the additions. Things like worm casings and guano (yah, poop), can give you much better results than a cheaper soil that has the exact same nutrient profile (N, P, K number).

What Kind of Soil Does Cannabis Need?

Let’s start by discussing what cannabis does not need. The biggest mistake inexperienced growers make is taking that lazy trip to Home Depot and choosing the seemingly-easiest option: that great big green bag of Miracle Grow that claims to have everything your plants need to thrive in the bag – including fertilizer.

Don’t fall for that trap. Ideally, you shouldn’t see “fertilizer” listed as an ingredient and stay far away from anything that claims to be extended-release or long-lasting.

A drop of water on the marijuana

A good specialty mix should provide everything your plants need to thrive without the addition of unbalanced chemicals and fertilizers. There are two main considerations you should be looking at when it comes to soil for your marijuana: texture and nutrient content.

Texture

Soil should allow for good drainage and air circulation while still allowing enough moisture retention to keep your roots happy. It needs to hold onto enough moisture so that the roots have easy access to nutrients, but not so much that air can’t circulate, rotting the roots.

 Guide To Soil Selection For Growing Marijuana

When you feel the soil, it should be light and spongy yet course.

A good soil may contain an additive that helps to break up the soil and keep it from clumping too tightly, or you can purchase that to add separately. Coco coir, peat moss, perlite or vermiculite are pH balanced additives that will do the trick.

Nutrients

The “dirt” itself only provides the growing medium and foundation for your plants’ root systems. But nutrients are what really feed the plants and cause them to grow.

Here’s where using a high quality mix or making your own gives you the upper hand. They’ll be established in the base mix so that they are broken down as food for your plants over time, providing nutrients like calcium, nitrogen, magnesium, phosphorous, potassium, and other micronutrients.

Some effective nutrients may include Azomite, Blood meal, Bone meal, Crustacean meal, Dolomite lime, Epsom salts and Wood ash/bio char.

Sprout of medical marijuana plant growing indoor

Providing these nutrients is just the first step, though. A healthy fungal population will work to keep the root system healthy through a symbiotic relationship.

Additives that can help establish a fungal population include humic acid, kelp meal or mycorrhizal inoculant/endomycorrhizae powder.

In addition, a good community of diverse bacteria helps to break down sugars in the soil and convert them into nutrients that the plants are able to use. These organisms will also serve as a bolster to the cannabis plant’s immune system, helping it to better combat disease, pests, and adverse environmental conditions.

Cannabis plant blooms, growing indoor.

Additives like bat guano, worm castings, and fishmeal can be very helpful here, too. They make for great sources of micronutrients and minerals that go into a thick and healthy bud.

Conclusion

The growth medium you plant your marijuana in can make all the difference to the life and vitality of your plant and its yield. The soil you choose needs to be able to support the functions of the plant through all stages of growth.

Even if you don’t fancy yourself with a green thumb, choosing the right soil can be easy if you follow these guidelines.