How to Grow Marijuana – Lesson 5 – Nutrients and Soil

Nutrient Deficiency

The Difference

There is a huge difference between how you use nutrients, depending on how you grow marijuana. If you grow hydroponically, you need to keep an extremely close eye on nutrient concentration, pH, salt buildup, the temperature of the water…basically the same as an aquarium.

Soil, on the other hand, disperses its nutrients throughout itself almost evenly, forcing the roots of the plant to grow outward and search for what it needs (which is what they are naturally supposed to do). This makes it much simpler to figure out your nutrient plan for growing in soil.

Planning the Menu

You will need to know where you want to go with your nutrient plan, but you also need to know where you are starting.

We recommend using an excellent soil, mixed with “Super Soil Concentrate“, both found here: What You Need to Grow Marijuana.

This mixture has fertilizers along with mycorrhizae, or microorganisms that live in the soil, delivering the perfect amount of nutrients to the plant and promoting root growth. For the first crop with this mix, you don’t need any extra nutrients. You will reuse the “living soil” for each successive crop, and supplement it with the nutrients in our recommended list.

Mix Your Soil

Since we are gearing this series of lessons toward growing four plants, we will also give you the mixture amounts as though you are growing four plants.


  • Start off by lining the bottom of your buckets with an inch or two of clean rocks or gravel (if you can’t find some for free, try a dollar store or pet store). Pour in a few inches of soil, so that when you are mixing in the next step, you won’t be disturbing the rocks that will allow for proper drainage.
  • For the mixture that we recommended above, and since we are using 3-gallon buckets, evenly distribute the three bags of Super Soil Concentrate into the buckets on top of the rocks and soil.Perlite
  • Add about a cup of perlite to each bucket and mix the Super Soil and perlite together.
  • Then, fill the bucket to between 1/3 and 1/2 full with soil, and mix again, doing your best to not disturb the rocks at the bottom.
  • Simply fill the buckets loosely, to the top with soil. Do not mix the top part.

Mycorrhizae and the Roots


The Super Soil concentrate that you mixed into the bottom of your buckets contains mycorrhizae, which are a very specialized type of fungus. This fungus grows symbiotically with the roots of your plants, meaning it helps your roots, your roots help it.

How this works is the fungus in the Super Soil colonizes the roots of your plants, and “collect” water and nutrients for the plants to grow. In return, the fungus thrives on the sugars and byproducts of photosynthesis that the plant performs (and the fungus cannot do for itself).

The mycorrhizae also produce enzymes that are toxic to most soil-borne microbial pathogens, meaning the plants are more protected against possible plant diseases in soil growing.

In this way, you are providing “living soil” for your plants to grow in.

After you harvest and remove each plant’s root ball, the mycorrhizae continue to populate the soil that remains in the bucket and help to “digest” any remaining organic material (roots left behind).

This means the soil is perfect to reuse. Just fill the hole with fresh soil and your new plants when they are large enough.

Sprouted Cannabis Planting the Peat Pots

Once your new seedlings have two to three pairs of leaves, its time for the tent:

  • Make a hole for one peat pot in the center of each bucket, about 1/4″ – 1/2″ deeper than the height of the peat pots
  • Gently place the peat pot into the hole, covering gently with the new soil, as you did when you planted the seeds
  • Once you have all of them planted, water each liberally with RO filtered water, but do NOT saturate the soil

Reusing the Soil

Since your soil is colonized and aerated with rocks and perlite, you just need to replace the soil you removed with the root balls of the previous plants.

The nutrients that initially came in the soil will have mostly been used by now, except for the excess roots left behind.

So, this is where we start to fertilize our crops. See What You Need to Grow Marijuana for our recommended nutrients for soil growing, and follow the instructions included. Start slow, and keep an eye on your plants. Not enough is much better than too much with nutrients.

Nutrient BurnIf you see the ends of leaves starting to twist or turning brown, you’ve given too much. Give pure, filtered water Nutrient Deficiencyduring your watering until they return to normal.

If the leaves are yellowing, they are not getting enough nutrients, and you should slowly increase the amount you use until they return to a nice, healthy green.

The leaves should be flat, and all the same colour (rich green, unless the strain description says otherwise), drooping slightly when the light first turns on, and completely stiff most of the “day” cycle.

We continue from here with more on nutrients and how plants use them with Lesson 6 – Watering Soil Grown Plants