Basics of Soil Preparation for Cannabis Growing

Hello again! This issue we are going to look at the process of preparing your soil for the upcoming seasons’ outdoor grow, where you would be putting seeds in the ground around mid-September and clones from end-September to mid-November.


Soil Preparation Benefits

When properly prepared, a soil mix can help with the following:

  • Improve the texture and air-to-water ratio in the soil
  • Increase the amount of nutrients available to your plants
  • Improve and increase root growth to go deeper
  • Improve nutrient uptake availability
  • Increase the micro-organisms and bacteria around root area
  • Keep nasty fungi away
  • Helps make plants healthier, bigger and stronger
  • Produce good organic/medicinal yields
  • Produce more intense psychoactive effects and deeper terpene profile/aroma
  • Increased yield
  • Saves you money on nutrient use
  • Saves you money on preventive and pest elimination products
  • Adjusts the pH in your soil
  • Improves your soil quality year after year for continued growing


How to prepare your soil for growing Cannabis

Testing your soil

Soil is a living part of Mother Nature. This is one of the key fundamentals and the most important part of your grow, as this is where your plants will get their nutrition via their root systems. For this reason, you need to make sure that your soil has the perfect physical, chemical and biological characteristics in order to obtain the best results from each of your plant stages: germination, vegetation and flowering.

In order to ensure that your soil is full of beneficial nutrients and microorganisms and has an airy, spongy texture as well as a good water/air ratio, you will need to know how to choose your growing area correctly. You will also want to study the soil you plan on using by taking various measurements, such as the pH and texture to know what nutrients you need to add. Depending on these results, you may need to either organic or organic-mineral products to your growing area.

This process is necessary if you want to know exactly what type of conditions you will be growing in. The soil that people normally have access to in their gardens does not usually contain the right nutrients or attributes for growing cannabis. Your ideal pH must be between 6 and 7, as well as having the capacity to absorb water, as some soils are super compact and clay-like, which make it difficult for air to flow through. Once you have all of that sorted, we are going to go through a list of steps for soil preparation for your cannabis plants.

Choosing your grow area

 The first thing you need to do is to choose the area in which you are going to start prepping the soil. This area should have the following characteristics to start off with:

  • Flat area or as flat as possible.
  • A sunny area with at least 6 to 8 hours of direct sunlight.
  • An area with plants, even if they are weeds, as this will indicate that the soil is somewhat fertile.
  • Discreet or covered, that is not visible to public.
  • Easy access to water.
  • You need at least 300-350mm depth and if the ground is not that deep you will need to make a raised bed.
  • An area that has healthy plants with no rot or insect infestations.

Growing in a Raised or Low/Sunken Bed

Once you have decided on your growing area, you will need to determine if you want to grow in a low or high raised bed, or if you want to grow straight in the ground by simply digging a hole. You must however keep in mind that each of these methods need to be done differently, so you will be able to know exactly how much of your soil you need to clean.

Raised Bed

To be able to grow your plant on a raised bed, you will need to make a rectangular structure that is 1-1.5m wide and as long as you like or need, which must be at least 300-500mm deep to hold your soil or growing medium.

Low/Sunken Bed

To put together a low/sunken bed you will need to mark out a rectangular area in the ground, in the same way as the raised bed, except this time you will not need to make a structure. The unworked soil around the hole will act as the structure and wall. You will need to find an area at least 300-500mm deep and if the soil you are growing in is of a good or high quality you should not have to add anything to it.

Growing straight into the Ground

When growing individual plants in the ground, all you must do is to prepare a small growing area of about 1-2m² per plant and make a hole that needs to be at least 300-500mm deep and as wide as you like. Check the quality of the soil, and if it is not up to standard, you will have to substitute it for a high-quality soil or substrate. The hole can be round or square, depending on your preference.

Please Note: Before making your raised/sunken bed or hole to grow in, you will need to clean the area. The next section contains the steps on how to do this.


Cleaning your Soil

 Cleaning your soil is fairly easy, as all you need to do is to remove any weeds in the area. To do this properly, the following steps are recommended:

  • Remove all weeds by hand a couple of days after some good rain, as this will allow you to pull them out with their complete root system, which will stop them from coming back and also assists with soil oxygenation.
  • Do not use any herbicides/pesticides to get rid of the weeds as you will contaminate your soil/growing medium and ruin any life that is in the soil.


Aerating your Soil

 This is the last and the most important step that you need to take in order to complete your soil preparation for your cannabis plants. There are different tools that can be used to do this, although the best and easiest is a garden shovel. It is particularly important to aerate your soil about 3 to 4 days after you have had a good soaking rain. If there has been no rain you can water your growing area well and then aerate it a few days later. This is called tempering and is done so that the soil has the right texture to be worked with, without ending up super compact or hard.

Also note that in order to know if the texture of your soil is right for starting to aerate it, simply scoop a small amount of soil into your hand and if you can crumble it without it sticking to your hand or without it turning to a powdery dust, then it is perfect. If this still happens wait another couple of days and check it again.


Now you proceed with the following steps:

Once you have decided on the chosen grow area and cleaned it up, you need to set up the grow. Our recommendation is applying a generous layer of one or more of the following organic or vegetal ingredients:

  • Mature sheep, cow or horse manure
  • Worm castings
  • Worked compost
  • High quality peat mix
  • Bat Guano

 Once you have spread the manure or any of the above-mentioned products, you will need to aerate your soil. The first part of this entails removing a small amount of soil from your growing area in order to have space to be able to work in.

Next, you will need to dig your spade in about 300-400mm and move all the soil towards the area that you have emptied out, while breaking up any large chunks of soil and removing any foreign objects such as stones, branches or roots.

Please Note: When preparing a hole for your plant, you will need to go as deep as you think is necessary, as the deeper and wider it is, the more space your plants roots will have to grow.

Once you have completed the above steps, add back the soil that you removed for the aeration process.

Once you have aerated your soil or substrate you will need to flatten the earth using a garden rake and get rid of any compact soil left on the top.


Long term soil preparation for the following Season

When preparing your soil or substrate for the next outdoor season, you can increase the amount of nutrients that your future plant’s roots can uptake as well as the amount of beneficial fungi and bacteria that develops over time, as well as creating a more balanced pH level. This will make for an environment that is more than ideal for cannabis plants, compared to soil prepared in spring.

If you do not have somewhere to create a raised bed for your plants or an area to grow directly in the soil, you need to start getting this work done as soon as you have finished the current growing season, around May or June. If you have a growing area or a raised bed area, simply follow these steps around the given dates.

Good luck for the grow ahead of you, stay Lit and Blessed.

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