What's So Cool About Super Soil? The Super Soil Recipe Breakdown. February 26 2014, 31 Comments

If you have been reading about cultivating indoors with organic soil then you've heard of SubCool's Super Soil. I admit to starting with this mix and thought I was really doing something special when I first went for it. I bought all the stuff and was really excited to use it.

My results were actually pretty good, but I've since moved on I think you should too.

Besides the "base soil" being purchased instead of made from scratch, I have many other issues. All in all, taking bagged soil and adding worm castings and nutrients isn't a bad idea, but it can be improved upon and money can be saved.

Here is the Recipe: 8 large bags of a high-quality organic potting soil with coco fiber and mycorrhizae (i.e., your base soil) 25 to 50 lbs of organic worm castings 5 lbs steamed bone meal 5 lbs Bloom bat guano 5 lbs blood meal 3 lbs rock phosphate ¾ cup Epson salts ½ cup sweet lime (dolomite) ½ cup azomite (trace elements) 2 tbsp powdered humic acid

Now I'll go through each item: 

  1. Bagged soil - WHY? when we are going to the trouble to mix all of this up anyways, me might as well save some money and increase the quality. The other factor here is having exact control over the inputs. These soils already have unknown quantities of nutrients and the quality control isn't perfect, what if you get a hot batch and then further amend it? I would avoid the potential room for problems and make a soil using many standard recipes but most go with 1 part peat, 1 part compost and 1 part aeration.

  2. Mycorrhizae: Adding this to your soil doesn't make sense and is a waste of resources. Anyone who works with mycorrhizae will tell you to apply to the rootzone at transplant or seedling stage. Obviously this super soil mix is for the bottom of the container and nowhere near the rootzone at the proper time. Basically just a complete waste of Myco.

  3. 25 to 50 lbs of organic worm castings: I agree with using wormcastings but that is a WIDE range to apply. Why 25 - 50? I think that when building your base mix you should be factoring in a certain percentage of castings and compost. Not adding to this all later on in a made up way.

  4. 5 lbs steamed bone meal - This is a by-product from the Cattle industry and is really not a good input for organic soil production. Fish bone meal however is great for this same purpose and is safer to use.

  5. 5 lbs Bloom bat guano - Guano is very expensive and really not neccessary. This is a fast release nutrient and is more in line with the feed the plant regimen instead of soil building. That and harvesting guano is rarely safe and sustainable, there are many reasons to avoid this.... Plus the Fish bone meal that we just mentioned has you covered already along with all the other plant based amendments and worm castings that you should be using.

  6. 5 lbs blood meal - More slaughterhouse waste and sure to be unclean. Why use the blood from McDonalds cows when you can add nitrogen so easily through alfalfa meal, fish meal and or worm castings.

  7. 3 lbs rock phosphate - This is the 3rd phosphate product and it makes sense because in a soil this rich and without the mycorrhizae actually working like it should there isn't going to be a very good way to access P. That's okay, in a properly built soil you don't need a million sources of P, the plants will get it and the biology and fungi will make sure of it. Not only that but soft rock phosphate is high in heavy metals like cadmium that are proven to be harmful. When growing cannabis, the trichomes will store the heavy metals and smoking the plant will not allow the typical body safety system of passing through the liver etc. before going into your blood. For this reason materials high in heavy metals are typically avoided.

  8. ¾ cup Epsom salts - Absolutely no reason to add more magnesium sulfate to a good soil mix. A little known fact about soil is that the Calcium to Magmesium Ratio will control the texture of the soil and adding epsom salts is a good way to tighten the soil and there are better ways to get sulfur, like gypsum.

  9. ½ cup sweet lime (dolomite) - Dolomite lime should be avoided as it is completely out of balance with the proper Calcium to magnesium ratios for proper soil building. Especially when considering long term no-till soil use.

  10. ½ cup azomite (trace elements) - This is good stuff and is just a "brand" name rock dust that has all the elements from A-Z hence Azomite.... thing is, that also includes heavy metals. While I'd use this in the veggie garden, many will avoid this in the medicine garden.

  11. 2 tbsp powdered humic acid - Good advice but humic acid typically purchased at the grow shop is from leanordite and isn't really helpful and is very expensive. Avoid this and get Ful-Power from Bio-ag and use it with waterings.

So then after all this work. You mix this up and let it sit for 30 days. Then use this in the BOTTOM of your soil container. What is interesting is that all though this makes sense at first glance... it's all way off. Nature doesn't have all the nutrients on the bottom in fact it's the opposite, all the plants in nature have the nutrients on the top. That is why building a soil, using mulch and topdressing work so well. It's things like this that make the real organic gardners and farmers laugh at all of us sometimes.

So if you've been using super soil, don't feel bad, I think we all did at some point and I owe Subcool a lot because he actually got this semi-organic mix discussed enough that the mainstream took notice... that alone was helpful at getting me to where I am today.

I hope this article helps!

Here is another article on a popular soil recipe called TLO: http://buildasoil.com/blogs/news/9885098-why-tlo-dissecting-the-rev-mix-line-by-line