The Best Soil Mediums For Growing Cannabis Indoors in Australia

This article is part of a series.
You can catch the rest of FAB’s Indoor Grow Guide at the link below!

Down to Earth

Crucial to growing good cannabis – in Australia, and everywhere else – is giving consideration into what kind of soil you wish to use.

There are many different options available. Will you go with real soil, organic soil, a clay pebble hydroponic setup, or maybe something in-between?

If you’re still not quite sure which medium you will use, you’re in luck. This is a guide for beginners. We’re going to give our opinion on what soil is best for those just starting out with their indoor growing antics.

Two Clear Frontrunners:

Coco Coir – and good ol’ regular Soil.

Coco coir is a very popular choice for indoor cannabis cultivation. It allows for complete nutrient control, encourages fast growth, and allows for a quick drainage of water.

Coco Coir is made from fibrous coconut husks, and can be used as a soil. Often referred to as ‘soilless soil’, coco has a similar look and feel to dirt. However, it contains absolutely no nutrients for your plants.

So, what about soil?

Well, soil is what most people are naturally familiar with when it comes to gardening.
Soil is the most popular medium forgrowers and producers of organic cannabis.Soil can be used for indoor growing – but it’s mainly used outside.

The big difference between the two mediums is that coco coir contains no nutrients, whereas fertile soil is alive and typically hosts entire ecosystems.

- Advertisement -

Pros and Cons of Coco Coir

Coco coir is a growing medium that provides growers with precise scientific control over the nutrients your cannabis plant receives. Coco has many similarities to the traditional hydroponic setups – where the roots grow in water, and the plant lays its roots in clay pebbles.

Instead, however, coco coir allows the plants to grow without any water pump/s running. There is a significantly lower chance of failure with coco, in comparison to traditional hydroponic methods.

Coco coir has excellent drainage. It is also incredibly absorbent. Coco makes it easier to keep on top of your plant’s hydration levels. Your plant won’t become parched too quickly. Still, coco will need more water than regular soil.

Coco coir is light and aerates well. It allows for the plants to grow really large, while still maintaining strong and healthy roots.

In our opinion, coco is definitely the easiest hydroponic medium to use. The biggest issue with using coco coir is the effort required to ensure the right nutrients and dosage for a high quality yield. However, this actually isn’t too hard if you’re dedicated and willing to do a bit of reading and researching.

Just be sure to infuse the right nutrients, and you’ll have next-to-no problems!

Pros and Cons of Soil

Soil, when compared to coco coir, has more beneficial nutrients and micro-bacteria to assist your plants in growing and fighting off disease. It’s easier to grow in soil, as you don’t need to be a nutrient expert for your plants to flourish. You just let nature take its course, man…

All in all, growing in soil is just less work. You don’t need to water it as often, and you don’t need to measure out nutrients nearly as much. It’s less time consuming. You do lose some scientific control over how your plants grow and what they’re fed. If you’re after a natural method of growing cannabis, however, soil might be your best option!

The One Key Ingredient …Perlite!

Something we haven’t mentioned yet is Perlite. If you use soil or coco coir, you’ll want to add some Perlite to your mix!

Perlite is a neutral addition to any soil. It aerates mediums, making them lighter. Perlite promotes root growth. Additionally, it keeps away unnecessary moisture and root rot.

Perlite is volcanic glass, basically. Little white rocks that help your plants grow better. Thank Mount Vesuvius!

We recommend using around 30 percentPerlite with your soil of choice. Using Perlite is strongly recommended, as your plants will simply grow better!

Where Do I Buy My Soil Medium?

Your best bet to buy coco coir is at a local hydroponic store. They’ll also stock Perlite. You can also order all of this stuff online through a quick google search.

Coco coir generally comes in two forms. An already-hydrated version – and one where it’s a tightly condensed brick, which you’ll need to hydrate yourself.

You can buy the bricks online, or at a nursery/hardware store. A 600-gram brick will make up about 9 litres of coco coir. They’re about $9 per brick on eBay. If you head down to Bunnings, you can get it for $2-3!

You can also buy a pre-mix of coco coir and perlite (50%/50%) at most hydroponic stores. It’s also available on eBay for $45! Mind you, this is a more expensive way of doing it. But you pay for convenience!

Find out how much soil/coco you’ll need.
Read our potting article.

If you’re after some premium soil, check out the CANNA Terra Professional soil from CANNA. You can purchase CANNA soil in Australia throughout a lot of hydroponic stores and nurseries. Take a look here to find your closest dealer.

Looking for some incredible organic soil? You can also check outEasy As Organics!They offer living soil which you only need to water – no nutrients are required throughout its growing cycle.

Use the code FABEAO2020 for 20% discount on all their Water Only Soil as well as our amendments. Check out Easy As Organics!

The Dirt

  • Whichever soil you choose, be sure to buy some Perlite. Mix it in at a 30-50% ratio to the soil.
  • Add sand and rocks to the bottom layer of your soil. This prevents bugs from living in the soil by cutting off the entries through the drainage holes.
  • 2cm of sand up top can also a good idea to stop the bugs. This shouldn’t be too much of an issue indoors, but it can happen!
If you have questions or comments relating to soil mediums, feel free to contact us, or leave a comment below.

Go back to our main guide here.
Get a wealth of information on Grow Weed Easy.

Joe Lagrasso

Author: Joe Lagrasso

Joe is a dreamer, entrepreneur and an all-around good guy. He wants to connect the Australian Cannabis community from businesses to consumers.

Joe Lagrasso
Joe is a dreamer, entrepreneur and an all-around good guy. He wants to connect the Australian Cannabis community from businesses to consumers.


Notify of
NewestMost Voted
Inline Feedbacks
View all comments
2 years ago

Also don’t buy soil with slow release nutrients!

Adam B
Adam B
1 year ago
Reply to  Kirk

And with this comment, yet again I don’t know what to get as the one suggested from Bunnings is slow release

2 years ago

Searles Organic Potting Mix sounds good. It has blood and bone, fish , kelp, bloom, 5in1 pallets? Should be good without slow release nutrients


[…] our main article on growing cannabis indoors, as well as for more information to help you decide what soil to use in your op. ‘Til next […]


[…] our main article on growing cannabis indoors, as well as for more information to help you decide what soil to use in your op. ‘Til next […]


[…] out our masterpost for Growing Cannabis Indoors in […]

11 months ago

Can only find Scotts premium organic at Bunnings and it has slow release oscomote .. HELP

2 months ago

I would like to know how to grow weed in doors plz 🙂

Would love your thoughts, please comment.x