Mr. Canucks Grows. Also known as Matt. Undeniably the most popular YouTuber who grows and also the strongest.

So I studied Matt’s growing style and it consists of 5 ingredients, Gaia Green Soil, Gaia Green Grow and Bloom Amendments, Worm Castings and Mykos which is mycorrhizae, Its a pretty simple mix and the only issue I had was trying to get the Gaia Green Soil.

I swear they got more restrictions to import this soil then most drugs. I tried to order it off of amazon, but it got denied at the border by customs. So, I reached out to the company and still couldn’t get it.

Mr Canucks Fan: 0:19
Mix and Preparation: 0:30
Price Analysis: 3:14
Lab Analysis: 3:43

Price wise, The total cost for a 5 gallon pot prorated is about $21 and the initial cost for all the supplies was $168 which is enough for 4 5 gallon pots.

A breakdown on the cost analysis is in the description. Its probably cheaper to get all this stuff at your local Hydroponics store but if you want to save on gas, check the links:

Promix HP $40.2 Used 1/5th bag, so $8.06
Gaia Green Bundle $68.00 4.85 lbs, used approximately 10 tbsps which is 1/15th or $4.53
Worm Castings $30 30 lbs, Used 1/4th of the bag so $7.50
Mykos $30 2.2 lbs, used 2 tablespoons which is 1/35th so 86 cents


I’m gonna start the plants off in
1.5 gallon plastic pot:
.375 gallon worm castings (6 cups)
1.125 gallon promix (18 cups of promix)
4.5 tablespoon of 4-4-4
Coat with mykos

The second pot Ill prepare will Transfer to 5 gallons fabric pot:
2.625 gallon promix
.875 worm castings. (14 cups)
5.25 table spoon 4-4-4
5.25 tablespoon 2-8-4
Coat with mykos

30 days into flower top dress with:
20 tablespoons of worm castings (1.25 cups)
5 tablespoons is 2-8-4

Promix HP is pretty basic and must be amended for the best results. After running a lab test on this soil, I find the pH runs high and all of the levels for macro and micro nutrients are acceptable. The only macronutrient that is at optimum levels is phosphorus.

Overall, the gaia green amendments for grow and bloom both have ideal NPK ratios that I am comfortable with and the addition of Mycorrhizae will help break down the nitrogen in the worm castings. Both of the gaia green amendments have a healthy amount of calcium, but the only issue I anticipate with this grow is the lack of magnesium. Remind me in the comments if any issues occur with this grow in my future videos. Other than that, this style seems solid and I’m looking forward to seeing how it stands up to the other slots.

This mix will be used in our Meta Soil Project which is a series of episodes that documents 6 different soil mediums grown side by side to see which ones produces the best quality.


Mr. Canucks Youtube Channel
💬 For questions, comments or to chat
To see the full day to day grow journal


  1. yo I love your content. it has been the most helpful out of everyone on YouTube. I want to start growing and would like to do them in larger scales because the goal for me is to start my cultivation business in cali. I got some questions because im planing on using bigger pots. on the last transfer where you put yours into a 5 gallon. im going to put a it in a 15 gallon so I was going to basically 3 times every ingredient. is that plausible and on the first pot, I was thinking to put it in a 7 gallon so it can have room for the roots to grow and just times it by 5.5 from the 1.5 gallon ingredients. Let me know your thoughts on this to get a better understanding on what to do.

    1. The problem with larger pots is that soil aeration is difficult at the heart and can lead to suffocation of the roots depending on the strain and rhizosphere. I would recommend adding a lot of pourous substrates to help with drainage and air. As for nutrients, yes it’s all ratios but just make sure you let the soil brew for like 10 days before use.

      1. I plan on using distilled water which is like 7 ph level. is that too high ? if not what’s the best way to have the approved water?

        1. if it distilled, that pH is negligible, only when you start adding ppm does pH really affect the soil and feeds

  2. I don’t know what is porous substrates. can you inform me on this ? im using feminized seeds and most of them produce large yield due to the information given by the company of the seeds. Also does my math seem to be correct for such large scale and should I water the soil for the brew or just let it sit ?

  3. Would adding some glacial rock dust in the soil mix help with the magnesium?

    1. Gaia Greens seems to have .9% but has a lot og Mn too so really depends on what you need. Epsom salt is much cheaper and has sulfur which a lot of modern strains need.


    2. What is the ph of the soil mixture your using after mix ?

      1. anywhere between 6.0-6.5 is ideal

  4. In this recipe can I switch out the pro mix for Gaia green living soil ?

    1. absolutely, it was actually intended to have the gaia green soil

      1. Awesome . Thanks!

      2. Could you use fox farm ocean

        1. Yeah you can, probably just need to remove 1-2 tablespoons of 4-4-4 then

  5. Would happy frog be an okay substitute?

    1. Yes, better than promix

  6. Can I sub out the promix with happy frog (bought a huge bag already)?

    1. Yes happy frog is better.

      Add a bottom layer of perlite as seen in the pot preparation video and run a slurry after everything has been mixed

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