Best Soil for Weed | Potting Soil for Growing Cannabis

If you’re asking this question, then we’re guessing you’re probably new to growing – or you’re serious about getting it right. We’re passionate about helping people grow their own plants, and we do so by providing some tried-and-tested tips, tricks and guides on how to find the best soil for weed so you can grow cannabis in South Africa from home.

If you’re looking to find the best soil for growing marijuana, then you’ve come to the right place. By the end of this guide to the best soil for marijuana plants– you’ll be able to pick the right soil with confidence. You can thank us with a snapshot of your yield later!

best-soil-for growing-weed

Best Soil for Cannabis

Before you get started, you’re gonna need some seeds. The right soil will do absolutely nothing if you don’t have something to plant in it. There are a lot of great places to buy cannabis seeds in South Africa.

Growing cannabis in soil is far cheaper, and a lot easier, especially for beginners. Whether you’re growing your weed indoors, in a small grow tent, or outdoors in the garden, whatever your choice of location, growing in soil is a great and natural way to crop fat, beautiful buds.

What’s more, is that soil is probably the most forgiving medium for growing. The biggest challenges are managing the watering of your plants, and the potential for problems caused by pests and diseases. Both of these risks are quite easily minimized through good management of your plants, as well as good hygiene.


When it comes to growing in soil, it is very important to choose (or make) a soil that will be best absorbed by your plants. The biggest mistake that growers make when using soil is to ‘stuff’ their soil with nutrients.

Overusing nutrients is not going to somehow yield a super-plant. Cannabis plants actually require different levels of nutrients during different stages of their life. And these nutrients are best absorbed at a pH level of 5.5 – 6.

How to Test the pH of my Soil?

For this you will need a pH tester kit. These can be bought at any nearby garden centre and they are fairly inexpensive. Or you could try this DIY method of testing your soils pH too.

Why is the Best Potting Soil for Cannabis Important?

Yes, cannabis is technically a weed, and yes, weeds can grow in a wide range of soils. But do you want your marijuana plant to truly flourish? To produce lots of THC, CBD and other cannabinoids? We thought so, therefore your future plants need the right balance of variables in their soil.

These are:

  • Good drainage (you do not want muddy, clumpy and waterlogged soil)
  • Also, good water retention
  • The correct balance of fungi to bacteria
  • A soil pH of around 6
  • The right texture (as in how does it feel? Yes. It should be loose and not compact or very hard)


Okay, now it’s time to get into the best soils available for you to buy in South Africa for growing your bud:

Best Potting Soil for Weed

So what is the best soil for marijuana? Getting a soil that has good drainage, good water retention and the perfect texture, all bagged up into a soil with the well-balanced cannabis nutrients in South Africa – is the aim here.

Here are some choices of the best soils for marijuana. They can be mixed up to create the perfect soil for growing cannabis plants:

Freedom Farms Soil Premium Growing Medium

This organic blend is formulated in South Africa mainly for organic growing practices and organic nutrients, which means its good soil for cannabis.

Freedom Farms produces a range of craft soils, for the connoisseur-grower and the gardener that requires optimal plant growth that can’t afford to skip a beat in production. According to some local South African growers, this is the best weed soil for sale.

Freedom Farms soil for weed


Coco Coir, Worm Castings, Compost, Perlite (10%), Vermiculite, Bone Meal, Gypsum, Fermented probiotic bran.


Around 6

Used for

  • Growing in small pots
  • Indoor, Greenhouse or Outdoor growing
  • Organic potting soil for vegetables, herbs and general plants
  • Growing organic marijuana plants

Where To Buy

You can buy Freedom Farms products from Grow Guru, along with loads of other products that will help you create the perfect plant (but more on that later).

Red Tractor Potting Soil

Red tractor soil for cannabis

If you’re planning on getting your bud on, this is a simple potting soil mix that has worked really well for many weed growers on a budget. Red tractor potting soil is great for mixing up the perfect soil for cannabis.

Where To Buy

Red Tractor has many retail outlets around South Africa, including some Mica shops, Stodels shops and Cape Garden Centre. Alternatively you can order from them directly via phone or email.

Tel: 021 987 1652

Cell: 072 674 2642



Coco coir is an ideal grow medium because it holds water exceptionally well. The physical properties of coco soil ensure an even balance of water and air in the root zone. It drains very well too which means its great weed soil.

Where to Buy

Coco coir is sometimes also referred to as Coco Peat or Palm Peat (don’t worry they’re all the same thing). Grow Guru stock a variety of sizes depending on how much you need. It’s not too expensive but you will need to buffer it to ensure it is the perfect environment for healthy root formation.

Grow Guru

Best soil for weed

After dealing with this supplier, we can no longer recommend their products or services. Full review coming soon.

If you’re looking to grow cannabis in South Africa, Grow Guru sells what every home grower needs (as you can probably tell from the number of times we’ve mentioned them so far).

They offer some of the best soil for growing cannabis and achieving maximum yields (which is the end goal after all). If you’re looking for grow mediums, they have it all.

Best Soil for Growing Weed Indoors

When it comes to the best soil for indoor weed, the soil you use will be fairly similar to the soil used outdoors. Sun, water and nutrients are everything. So go and get yourself some Seagrow (not for your germinating seeds or seedlings just yet) from your local spar or garden centre, and ensure your plants get enough sun and/or light!

For indoor growing it might be a good idea to look at investing in a grow light. These can help create some sunlight for your babies especially if you’re using a grow tent and natural vitamin D is lacking.


How to Grow Marijuana in South Africa

So how does one go about mixing up the perfect soil for growing weed? Well, if you’re going with something like Freedom Farms premium growing medium (see the ingredients), you will notice that it has everything your plant may need, you’ll just need to top it up as your plant happily eats through the nutrients in the soil.

Here are the ratios for making the best potting soil for cannabis:

The Germination Phase:

During this phase, nutrients, drainage, sunlight, etc. don’t have a say – they only feature once we’ve successfully helped our babies through this phase first.

Here are two methods you could try for this phase:

A: Gently plop your seeds between two wet paper tissues (or cotton buds) and place them in a plastic container. This is done indoors, and try to place the container in a spot where there will be higher humidity levels inside the container (put the lid on top of the container, BUT DON’T CLOSE IT). Temperatures in the container should be around 23 °C, and moist, but not overly wet. End goal? You’re waiting to see the first few millimeters of the root breaking through. This can take a few days, so be patient.

B: Fling your seeds into a glass of drinking water and wait a day or two until seeds have cracked. Keep waiting until you see the first few millimeters of the root. Place your cup somewhere light doesn’t reach it, but it will still be warm.

The Seedling Stage:

Your marijuana plants will never be as vulnerable as they are in their seedling stage, and this is often when people think they should jam-pack its diet with nutrients. Nope, don’t do that. ‘Nutrient stuffing’ is a mistake that can easily end your plant’s life before it’s even properly started, and some well meaning nutrient supplements could easily poison your seedlings.

Plant seedlings in very small individual containers, such as a peat pot, or even a Jiffy pellet. However you can’t keep them in this forever, as their roots will outgrow the small space. Both of these mediums mean that they can be directly planted into the soil/bigger pot when the seedling is established and ready to move on.

If you provide your seedlings with nutrients when they are too young, they might have a sort of nutrient overdose. So as long as your initial potting soil for weed is of a high quality, you shouldn’t need to worry about adding any more until after a minimum of a few weeks.

The Vegetation Phase:

The vegetation phase comes after the germination and seedling phases, the stem grows thicker and taller and will begin to develop new nodes. These nodes will produce more leaves and even some new branches.

For this important stage of your plant’s life, high quality organic soil that is “minimalist” when it comes to pre-added nutrition works best.

Bottom half of the pot: equal parts coco, perlite and worm castings

Top half of the pot: 70% worm castings, 25% coco and 5% perlite (used for aeration and water retention).

Molasses and Other Flowering Nutrients:

Your plant will naturally eat through what you are growing it in, so as the plant grows – soil levels will drop. Therefore, in this stage, you should be topping your soil up with pure worm castings and feeding it with water and Bio-Bloom or Molasses.

Bio-Bloom should be mixed at around 4 ml per litre.  When watering your plant alternate between using normal water and the Bio-Bloom mixture.

In addition, blackstrap molasses is a great nutrient to offer your plant during mid-to late-flower. One of blackstrap molasses uses it’s known best for is as an agent to deliver important nutrients to plants, such as carbohydrates, amino acids, and minerals. The benefits of blackstrap molasses will also help you bulk up the size of your buds.

Simply add between ¾ and 1 tablespoon of molasses per plant (depending on plant size, most will be fine with ¾ of a spoon) into your watering regime once a week, and stand back to watch the results.

You can buy blackstrap molasses here, and it’s one of the most beneficial organic nutrients for your plant, that also happens to be one of the cheapest. Your plants won’t be disappointed with a little added sugar.

Final Thoughts on the Best Soil For Marijuana

This guide on the best soil mix for cannabis should give you an idea of what to look for when purchasing your soil. And remember that when growing marijuana; sun, water and nutrients are your best friends, so you may as well start getting to know each other!

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