Using Super Soil for Autoflowers

Using Super Soil for Autoflowers

Image result for super soil

Growing Autoflowers in Super Soil.

Are you scratching your head as to whether or not you can use Super Soil for autoflowers? If you’ve done your research then you may have read online that autoflowers don’t need high levels of nutrients during their early life.

Whilst that is true, you can make an autoflower friendly super soil that contains enough nutrition to sustain your plants through their entire life.

Making your own Autoflower friendly ‘Super Soil’

You will need:

The above recipe should yield you around 220L of auto-flower friendly super soil at the cost of $320, quite a costly option considering you may still need additional nutrients and compost teas during the flowering stage, which can run around $50.

Taking into consideration the fact autoflowers don’t typically yield much, your ROI will lower than using coco-coir and synthetic nutrients.

You can expect to pay around $130 for 220L of coco-coir, and 90$ for nutrients broken down into $30 for base nutrients, $10 for CalMag, and $50 for PK boosters during flowering.

But if you really want to grow some organic nugs, then keep reading.

1) Blending the soil

  1. Lay your tarp out and pour out 2/3 bags of soil.

  2. Add the Bone & Fish Meal

    Adding Bonemeal

  3. Make sure you mix it properly!

    mix it up

  4. Add your remaining bag of soil to cover the bone and fish meal


  5. Add your Earthworm Castings & Bat Guano


  6. Add your Perlite & Vermiculite


  7. Mix it up for a good 5 minutes


If you’re doing this indoors, or want to be a bit more discreet then i’ve found this neat pool, it folds away and you don’t need to blow it up.

2) Composting the soil

This process is often called ‘cooking’ due to the heat that is produced from the biochemical reactions and should take you around 6 – 8 weeks.

It’s a vital step when creating a super soil blend and will ensure that the mixture is evenly “cooked”, ensuring that the bacterial, fungal and nutritional levels are even throughout the mixture.

Week 1:

Over the next week, continue to regularly mix the soil evenly – once in the morning and once in the evening until the soil is no longer patchy in color.

After a week has passed, or when the soil is a uniformed color begin to store the soil in containers, you will need 5 x 50L containers for this recipe. I’m assuming that you don’t have 4 empty garbage cans so these potato growing sacks work great (and they’re cheap!)

Week 2:

Place your containers in a sunny spot in your garden, this is why potato sacks work great because they’re so discreet.

Begin adding water to your containers and give it a good stir to start the microbial and fungal life. Your soil should be moist but not wet whilst composting, the idea is to keep the mix moist and contained.

If your soil isn’t contained, it will dry out quickly, stopping the microbial process faster than it started. It’s important to keep the soil moist by covering your containers.

Week 3-8:

Keep your composting soil in a sunny spot in your garden, checking on it regularly, twice a week should be enough and adding water when needed to keep the mixture moist, it’s completely normal for the compost to be hot to the touch – this is why it’s called cooking and you can be assured that you are doing a good job and making good quality super soil.

Repeat this process for a minimum of 4 weeks, the longer the better as with any super soil.

3) Using your AFF super soil

Now that you have some nutrient-rich super soil, It’s time to get growing – start by choosing a suitable container for soil, I personally like to use smart fabric pots because they are breathable allowing lots of oxygen to the soil and the roots.

Get Smart Pots for growing cannabis at!

Plants grow faster in smart pots than traditional hard-sided containers because roots thrive on oxygen and they let air in from the sides.

The oxygen from the sides also prevents the roots from dying or wrapping around the edges of the pot, so a plant grown in a smart pot won’t get rootbound!

They won’t set you back much either! I picked up 5 x 10Gal pots for $13 on Amazon

Starting autoflowers in your AFF super soil:

Because of their sensitive nature, you only want to fill the bottom 1/3 of your starting container with super soil and the remaining 2/3 with regular inert coco-coir.

By only having nutrient-rich soil in the bottom of your container, this will help prevent your seedlings from becoming stunted due to nutrient burn as they won’t receive the nutrients from the super soil until they have sufficiently grown and their roots can reach the bottom of the container.

It usually takes 2 weeks for the roots to reach the nutrients which is ideal.

Feeding your super soil

The main benefit of using super soil is the absence of synthetic nutrients, you literally only need to give your plants water as your soil has been set up to feed your plants.

You can give your autoflowers compost tea and flowering boosters during the flowering stage, organic or synthetic – that is up to you, but this is how much water you should feed your plants in a 5L smart container.

  • Day 1 – Give 1 cup (250ml) water per plant
  • Day 3 – Give 2 cups (500ml) water per plant (wait 3 days after this one since you just upped it)
  • Day 6 – Give 2 cups (500ml) water per plant
  • Day 8 – Give 3 cups (750ml) water per plant (every 3 days after this)
  • Day 11 – Give 3 cups (750ml) water per plant
  • Day 14 – Give 4 cups (1 liter) water per plant
  • Day 17 – Give 4 cups (1 liter) water per plant
  • Day 20 – Give 5 cups (1.25 liter) water per plant
  • Day 23 – Give 6 cups (1.5 liter) water per plant
  • Day 26 – Give 6 cups (1.5 liter) water per plant
  • Day 29 – Give 8 cups or 1/2 gallon (2 liter) water per plant
  • Continue giving 1/2 gallon (2 liters) per plant every 2-3 days. You may need to give more at a time or more often as plants get bigger. If you ever get any significant runoff out the bottom, it means you should be giving less water at time.

Why can’t I use a regular super-soil recipe?

Unfortunately, most super soil recipes aren’t usually suitable for growing autoflowers, this is because of the high level of nutrients that are present in good super soil.

Stunted autoflower due to nutrient excess.

Whilst super soil works great for photoperiod strains from vegetative to flowering, unfortunately, the same can’t be said for autoflowers.

Autoflowering plants are genetically smaller and therefore have a much smaller nutrient requirement, and because of this, they’re much more susceptible to nutrient burns.

I’ve written a recipe that will work great for all autoflowering strains, made from a rich blend of soils, coco-coir, perlite, vermiculite and nutrient-rich additives.

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Perlite and Vermiculite have great oxygen and water retention properties, although clay pebbles are becoming more popular and are now commercially available as a 60/40 mix.

I wouldn’t recommend using super soil to start autoflowers. The main reason being that you can’t really clone an autoflower so it means germinating a new seed for each plant, a costly matter given the chances of failure from starting seeds in a hot mix is pretty high.

If you’ve decided to grow autoflowers in super soil, It’s important that you dilute the concentration of nutrients, that’s why we’ve written an ideal super soil recipe for growing autoflowers.

Super Soil Alternatives for Autoflowers

If you still want to grow amazing quality buds but are put off by the thought of going through the effort of acquiring, measuring and mixing your soil and additives together, you might find it easier to go with the option of using an inert growing medium and adding synthetic nutrients, as is the most popular option amongst growers.

A couple of mediums apart from super soil are available:

  • You can grow in regular potting soil in which a light feed of nutrients will be needed
  • You can grow in coco-coir which is the fibers from coconut husks when growing in coco-coir nutrition is required from the start.

If you decide to buy a pre mixed soil, take into consideration that you will need to supplement the soil with additional nutrients further down the line.

Whether you use synthetic or organic nutrients, you will need to apply a PK booster to make sure you are yielding bountiful harvests.

Also take a read of the blog posts we wrote for the best PK boosters, and why you should be using molasses with your soil grow.

What is Super Soil?

The term “Super Soil” was coined by Cannabis Cup winner and record winning seed producer, Subcool as a catch-all phrase to describe the process of creating the perfect soil mixture, resulting in a large harvest regardless of your growing expertise.

Typically, Super Soil contains organic soil, an aeration substance such as vermiculite as well as a wide range of additives responsible for introducing a bacterial and fungal population.

Additives often include Bat Guano(poop), Worm Castings(more poop), Humic Acid and Kelp Meal to name a few.

The basis for any Super Soil can be broken down to 3 main elements:

  • Creating your starting point, mix 2 parts organic soil with 1 part of vermiculite/perlite.
  • Create a healthy bacterial presence by introducing strong sources of nutrition such as Kelp, Bone Meal, Bat Guano, and Oyster Shells to name a few.
  • Developing a fungal population by introducing supplements such as humic acid or mycorrhizae powders, this will help your plants uptake nutrients.

1) Creating a base medium:

Combining 2 parts of organic soil to 1 part of Perlite/Vermiculite will give you an excellent starting point to begin creating your own super soil, from here you will need to establish bacterial and fungal populations to keep the soil alive.

2) Establishing a fungal population:

mycorrhizae drastically increases root mass.

Fungi are extremely important and a key factor in creating diverse microbiology within your soil.

Fungi will thrive in the nutrient-rich super soil developing a strong, symbiotic relationship with the plant’s roots where the fungus “latches” onto the roots, growing along side-them resulting in better nutrient uptake for the plant.

A few trusted amendments that help build fungal life are Kelp Meal, which is basically dried and ground seaweed and Humic Acid, more recently – endomycorrhizae powders have entered the market with promising results.

3) Establishing a bacterial population:

Equally important to your soil is bacteria, bacterial populations will break down complex carbohydrates into various nutrients as well as macronutrients which your plant will then feed off.

Having a strong bacterial presence alongside fungi will help your plant’s immune system better develop, making them more adaptable to fight off pests and diseases.

Worm Castings are the go-to option for colonizing a bacterial population and can often make up to 20% of the total super soil mix.

Pros and Cons of using Super Soil

It’s a great Organic medium.Potential to burn plants if not used properly
You use less nutrients during the veg stage.Not as easy to manipulate as liquid nutrients.
Mimics the natural outdoorsYour harvest may not be as large.
Packed with nutrients and micronutrients.
No need to flush plants.

Author: tgallone

3 thoughts on “Using Super Soil for Autoflowers

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