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The Best Soil for Growing Marijuana

The Best Soil for Growing Marijuana

So you have your seeds or clones, you have your pots and other equipment, you have the enthusiasm to start growing marijuana at home, but there appears to be something missing from this list. Ah yes, the soil. When growing marijuana, the type of soil you choose can make or break your plants. Don’t believe us? Keep reading this article on the best soil for growing marijuana to find out why!

Marijuana, a needy lady

Marijuana is a very needy plant. It needs your attention and care and comes with its own set of requirements for successful growth. These requirements include:

  • Good water quality at right temperature and pH
  • Good atmospheric conditions
  • Sunlight/ grow lights 
  • Nutrients
  • Growing medium (soil)

Many people will argue that the growing medium or soil is the most important consideration and they wouldn’t be entirely wrong.

Think of soil as you would a home. This is where it starts its life as a seed, grows and blossoms into adulthood. A good, nurturing home is more like to produce a healthy, mature adult than a poor, toxic home.

What makes soil “good”?

The best soil for growing marijuana is one that:

  • Has a slightly loose texture
  • Has good drainage 
  • Is Well Aerated 
  • Has the right pH

Slightly loose texture 

Image Courtesy of Gabriel Jimenez–

Soil texture is determined by the size of its particles and how close they are to each other. This determines how well the soil drains and retains water if the roots will be able to penetrate it easily and how well it will retain air.

Good soil has a slightly loose texture that allows it to retain the ideal amount of water, allows air to pass through easily and promotes root penetration. 

Good drainage 

The best soil for growing marijuana has good drainage. Good drainage means that the soil won’t get waterlogged easily, nor will it lose water too quickly.

Think of your kitchen sink with its drain. If you had a poor drain, then water in the sink would take a longer time to pass through it. This can put your kitchen at risk if getting flooded. If that happens, you can expect damage and even destruction of furniture and appliances. 

It’s the same for cannabis and any other plant. If the soil gets choked, the roots are starved of essential gases such as oxygen and carbon dioxide which can cause the plant to die.

Note that if the soil drains too quickly, the plant will not have enough time to absorb the water and the nutrients within it. 


A well-aerated soil allows air, water, and nutrients to penetrate its depths and provide nourishment to the plant’s roots. A well-aerated soil is the best soil for growing marijuana.

A poorly aerated soil may become compact, acidic and waterlogged. This reduces the changes a producing a healthy weed plant.

Right pH

pH refers to how acidic or alkaline something is. When it comes to the best soil for growing marijuana, you want to be on the slightly acidic side, within 6.3 to 6.8.

Slightly acidic soil allows the plant to absorb essential nutrients such as nitrogen, phosphorus, and potassium. If the soil becomes too acidic, your plants may start to wilt and growth will be stunted.

How to spot the best soil for growing marijuana 

You can get an indication of the best soil for growing by its appearance. 

Good soil will appear dark and rich and will look slightly crumby.

To test its drainage and aeration, all you have to do is water it. If there is still a film or pool of water on the surface for more than 30 seconds then that soil has poor drainage and is likely to have poor aeration. Soil that is too muddy or takes forever to drain out the bottom is retaining too much water, making it poor soil for growing great weed. 

If you’re growing outdoor, here’s a test that you can do: Outdoor soil drainage test 

Examples of the best soil for growing marijuana 

Soils are typically a mixture of sand, silt, and clay. 

Sand has good drainage and high oxygen levels but has poor water retention and nutrient content. 

Silt already contains nutrients and retains water, but its drainage is poor and it typically has poor aeration. 

Clay has good mineral content and stabilizes plants, but it has poor drainage and is hard to work with. 

See Also
Enhancing Cannabis Terpenes

So which of these would be the best soil for growing marijuana? Well, why choose when you can combine all three? This way you can take advantage of their advantages and compensate for their disadvantages.

This type of soil is called loam. When squeezed in your hand, it forms a loose, unstable ball which means that it has great texture and is well aerated. Loam is also well-drained, has high oxygen levels, is naturally fertile and is easy to work with. 

Image Courtesy of Neslihan Gunaydin–

Loam can be costly, but that is because it is the best quality soil to work with. Loamy soils are not all the same and will have different ingredients. These ingredients can include:

  • Perlite
  • Vermiculite 
  • Plant food
  • Fish meal
  • Bone meal
  • Earthworm castings
  • Bat guano
  • Peat moss
  • Coco coir (coco fiber)
  • Compost
  • Kelp

While it is unlikely that you will see all these ingredients in one soil mix, these are things that you should look out for.

The best soil for growing marijuana for the beginner is one that you won’t have to add anything to. There are many soil mixes on the market like this! 

Soil mixes to avoid

If you are growing on a budget, then you are probably not going to go for the big-name soil brands. In your search for budget-friendly soil, do not choose a mix whose ingredients you can’t are unsure about, for instance, a vague list or in a different language.

Soil with a lot of big wood chips is not fully composted and is likely to have poor nutrient content. If it is pale in appearance, it is also likely to have poor nutrient content. Don’t get this confused with perlite which are small, white looking particles the promote aeration and drainage.

For more on what not to do, our friend The Rev has some key pointers

Mixing soils 

If the soil looks like a solid object, rather than fluffy crumbs, that soil may be too heavy and can stunt the growth of your marijuana plants.

“Time release” is another term you should look out for. Time-release chemical nutrients are released gradually over time and can retard bud growth in the plant’s flowering stage.

And no, don’t just go digging dirt from a random spot in your yard. That’s probably bad soil too, especially if you don’t have a home garden.

Next step

Now that you know all the characteristics of the best soil for growing marijuana, the next step is really to go ahead and buy your soil. Once you do that, you can move on to how to care for your cannabis plants and in no time you’ll be ready to harvest!

Happy growing!