Subcool’s Super Soil – Improved !


Subcool’s super soil is the most popular soil recipe used for the last 20 years but there are now variations on that recipe. I have included them here after Subcools. I have not tried these other mixes but they have been well received and have very good reviews. Subcool’s super soil is my first choice for a super soil, but all of these mixes will be good for growing organic marijuana .

  1. Subcool’s Super Soil – Improved by Subcool !”The Original  and Origin of Super Soils”
  2. Clackamas Cootz’s (Super Soil) !
  3. Rev’s True Living Organics (Super Soil) !
  4. Moonshine Man’s (Super Soil) !
  5. Lumperdawgz’s (Super Soil) !
  6. Slauson’s (Super Soil) !
  7. Lc’s (Super Soil) !
  8. Can’t Cook The Super Soil ? Do This !
  Tom’s Facts On Subcool’s Super Soil Recipe !

Why Use A Super Soil ? Why is this recipe called “super soil” ? A fellow grower of organic medical marijuana who goes by the name Subcool developed this recipe, and coined the termSuper Soil  ” super soil “.  Subcool calls his organic mix this because it takes all the guess-work out of organic growing. With Subcool’s super soil you don’t have to worry about the “PH” of the soil nor do you have to concern yourself with the “PPM” ( parts per million) of the soil nutrient level. Once this recipe is mixed and your plants planted in it all you have to do is water your plants when needed. No need to fertilize at all from newly potted plants to harvest. Subcool’s super soil has all of nutrients needed for the entire growing process. The original formula was developed around 1993 over 20 years ago. Subcool’s super soil recipe has changed little over the years despite his tweaking throughout this time. I think everybody should take advantage of this research that has already been done for us. I use Subcool’s super soil recipe for the large medical marijuana grow I am in charge of for a dispensary here in Colorado. I highly recommend this recipe for growing organic marijuana as this is a rich organic soil that will bring out the best in your plants. There is nothing sweeter than the taste of properly grown and cured organic medical marijuana.This is his latest improved published recipe.

kids poolIn order to mix this organic soil recipe you will need something to mix it in. I have found that a small plastic children’s pool works well and cost about $15. If you are mixing a large batch I recommend a small portable cement mixer. I use the children’s pool at home and a cement mixer at the dispensary grow.50L_drum_Concrete_Mixer_jpg_250x250

   Base Soil ! This soil mix calls for starting with a base of store purchased bagged high quality organic soil. Yes you read that right a commercially produced organic soil, bagged and in a store near you. The fact that you can start with a bagged organic soil makes this mix easy to make. A good organic soil will cost you between $15 & $22 dollars for a ten gallon bag. Now you don’t have to buy bagged soil for your base soil you can make it yourself. However, some of the ingredients found in these commercial organic mixes, not only come from around the world, they can also be hard to find. There are many growers that make their own organic base soil, and it can be just as good if not better than the bagged soil but it Roots Organic Soilrequires a lot of planning and work. I useRoots Organics Soil as my base organic soil and it is one of the bagged soils that Subcool  suggests to use. Here are some of the ingredients that are in Roots Organics Soil” : peat moss,composted forest material, coca fiber, pumice, perlite, glacial rock dust, oyster shell flour, green sand, bat guano, fish bone meal, kelp meal, soybean meal, alfalfa meal, leonardite, k-mag, earth worm casting, and mycorrhizae.   Other good commercial organic soils include Harvest Moon and Fox Farm . I am sure there are others that are very good. You will just have to experiment with them and see which organic soil you like the best.

The original Subcool’s super soil recipe calls for starting out with 8 bags or 80 gallons of base mix. This is a lot of soil for the small grower and actually a large batch to mix even for a large grow. IOLYMPUS DIGITAL CAMERA have found that mixing one ten gallon bag at a time is the easiest way to mix, whether you mix in a plastic pool or a small cement mixer.  The cement mixer I use at the dispensary grow holds ten gallons of soil comfortably without spilling. The plastic pool is also a perfect size for mixing ten gallons of organic soil without breaking your back.

Subcool’s Super Soil- Improved by Subcool

    Subcool’s Super Soil Recipe Improved, Large Batch :

  • 8 ten gallon bags of high quality Organic Potting Soil  Such as “Roots Organic Soil”
  • 25 – 50 pounds of Organic Earthworm Castings
  • 5 pounds of Blood Meal (12-0-0)                    Roots Organics Soil
  • 5 pounds of Bloom Bat Guano ( 0-5-0)
  • 5 pounds Fish Bone Meal ( 3-16-0)
  • 3 pounds Rock Phosphate (0-3-0)
  • 3/4 cup Epsom Salt
  • 1 cup Dolomite Lime
  • 1/2 cup Azomite
  • 2 table spoons (Tbs.) powdered Humic Acid

Subcool’s Super Soil Recipe Improved, Small Batch :

  • 1 ten gallon bag of high quality Organic Potting Soil  Such as “Roots Organic Soil”
  • 3 to 6 pounds of Organic Earthworm Castings  (1 lb. of casting = about 1 gal.)
  • 10 ounces of Blood Meal  ( 10 oz. of blood meal = about 1 & 1/2 cups)
  • 10 ounces of Bloom Bat Guano ( 10 oz. of guano = about 1 cup)
  • 10 ounces Fish Bone Meal ( 10 oz. of bone meal = about 1 cup)
  • 6 ounces Rock Phosphate
  • 1&1/2 tablespoons Epsom Salt (magnesium sulfate)
  • 2 tablespoons or 1 oz. (liquid measure)of Dolomite Lime
  • 1 tablespoons or 1/2 oz. (liquid measure) of Azomite (trace elements)
  • 1 teaspoon of powdered Humic Acid

What Are These Ingredients For ? 

  • Earthworm Castings = provide a rich variety of soluble plant nutrients with growthearthworms enhancing compounds. Also a diverse population of microbial life within a base of organic matter rich with nutrients. 
  • Blood Meal = organic source of nitrogen. 
  • Bone Meal = organic source of phosphorus
  • Bat guano = organic source of phosphoric acid 
  • Rock Phosphate = organic source of phosphorus 
  • Epson Saltsorganic source of magnesium sulfate which helps in breaking down nutrients in the soil making them available for plants use. 
  • Dolomite Lime =  Organic lime that buffers the soils Ph levels to keep Ph stable 
  • Azomite = Organic compound that provides all trace elements a plant may need 
  • Humic Acid = Organic compound that improves nutrient uptake and stimulates microbial activity.

Mix Ingredients Together, Then What ? No, Subcool’s super soil isn’t ready to use quite yet. Next you want to “cookthis mix. No you’re not going to put in the oven you are Red trash can for cooking soilgoing to re-bag the soil ( put it back into the bag the base soil came out of) or put it into some other suitable container such as a garbage can. Once into the storage container you want to water the mix lightly and mix until all the soil is moist but not wet. You want the soil mix moist to activate the mycorrhizae ( microbial activity) and begin dissolving the powdered garbage can lidingredients. Don’t forget to close your bags and put a lid on the garbage can. You want the containers closed to trap the heat in. Just like a compost it will create its own heat. Now you want to put your container somewhere where it can sit in the sun most of the day and “cook”. You want this organic soil mix to “cook” for at least a month.

Cook Mix In The Sun ? Yes you want this organic mix to bake in the sun just like you would a compost. In fact that is what you just mixed a Super Organic Soil Compost ! Because whole ingredients like, bone meal, blood meal, rock phosphate, azomite, and the bat guano, need to break down, you want it to compost (cook). You do this so these ingredients begin to break down into usable water-soluble particles that will then be available to your medical marijuana plants.

No Time To Cook ? I don’t recommend not cooking your “super soil”. However if you just can’t let it cook you do have another option. I haven’t always been able to let my soil cook for a dispensary grow where I work . My solution was; with my first watering I watered with one tablespoon of water-soluble Mycorrhizae, one tablespoon of Magnesium Sulfate (Epsom salts), one teaspoon of powdered Humic Acid, and a quarter of a teaspoon of Azomite. By watering the first time using these ingredients, it seems to jump-start the biological process driven by the mycorrhizae micro-organisms which in turn allows the natural production of available nutrients in the soil. These measurements are for a 7 gallon pot. I have used this method on hundreds of plants with excellent results. I must reiterate ; Cooking of the soil is the preferred method !

Not For Seedlings Or Clones ! This organic soil mix is not intended to plant seed in, nor is it for cuttings, or for your newly rooted clones. This soil mix is too hot ( too many available nutrients) for young plants roots. This soil mix is also too hot to use by itself.

For Bottom 1/3 of Pot !  This mix is so strong that it should  be in the bottom 1/3 of the pot for most varieties of medical marijuana. There are a few varieties that will want more of this super soil, up to 1/2 of the pot. The rest of the pot fill with just the organic base soil like “Roots Organics Soil”. 

Pot Size ? The best pot size is debatable, but I have found that a 7 gallon pot is

7 gallon pot
7 gallon pot

adequate and what I use the most. I also like to grow in a 10 gallon pot for a large growing space. I have grown successfully in 3 gallon and 5 gallon pots also. The SOG (sea of green) method uses 1 gallon pots. I would not use this super soil in any pot smaller than 5 gallons.

Good For The Whole Crop Cycle ! With Subcool’s super soil there will be no need to fertilize ever ! Everything your growing organic marijuana wants from vegetating through flowering to harvest, is in this super organic mix. What more could your organic medical marijuana want ? All you have to do is water ! How simple is that ?

Clackamas Cootz’s (Super Soil) Mix !

Clackamas Cootz is an “organic canna forum” guru, and his soil mix is solid and incredibly simple. If you want to make a water-only, living organic soil, try out this mix:

Base mix:

  1. 1/3 sphagnum peat moss
  2. 1/3 aeration (perlite, pumice, lava rock, rice hulls, etc.)
  3. 1/3 HIGH QUALITY compost and/or worm casting

To every 1 cubic foot (~7.5 gallons) of the base mix add :

  1. 1/2 cup kelp meal
  2. 1/2 cup crab shell meal
  3. 1/2 cup neem or karanja cake
  4. 1 cup gypsum
  5. 1 cup CaCO3 (oyster shell flour, dolomite lime, calcitic lime, etc.)
  6. 4-5 cups rock dust per cf Rock dust should be super fine: the consistency of flour.

That’s it! The key here is quality compost/worm castings. That is the LIVING part that makes this whole soil mix work. So it must be HIGH QUALITY. Water with dechlorinated water and you are set!! No pHing, no checking the TDS of run off, no cal/mag, no BS!

Rev’s True Living Organics (Super Soil) !

There are folks that rave about this mix but I find it ridiculous. In my opinion some  unnecessary  and useless or practically useless ingredients, such as Greensand and Feather Meal. Sometimes simpler is better.

TLO Mix 2011 Supernatural Version 2.1 BY: THE REV
Master Soil-Mix Recipe

2 gal Quality Organic Soil-mix
2 gal  Coir (coconut fiber)
2 gal Perlite (small grain size)
2 gal Earthworm Castings
1½ cup Grow or Bloom ‘Pure’ by Organicare (or 1 cup 5-5-5)
½ cup Greensand
¾ cup Ground Oyster Shells (1 cup if no crushed oyster shells)
1½ cup Crushed Oyster Shells (optional)
½ cup Dolomite Lime (powdered)
1 cup Prilled (pelletized) Fast Acting Dolomite Lime
¼ cup Blood Meal
¼ cup (heaping) Feather Meal
1 cup un-steamed  Bone Meal
½ cup Bulb Food (3-8-8 as one good N-P-K example)
¼ cup Soft Rock Phosphate (powdered)
½ cup (heaping) Gypsum (powdered)
½ cup Kelp Meal
4 cups (heaping) Composted Steer Manure (this inoculates your mix with specialized bacteria and primo organic matter)
½ cup Azomite granular
1 cup Humic Acid ( granular or powdered)
1 cup Organic Alfalfa Meal
1 cup (heaping) organic rice (important for the good fungi in this soil-mix)

Next you want to “cook ” this mix. Put this mix into a suitable container such as a garbage can. Once into the storage container you want to water the mix lightly and mix until all the soil is moist but not wet. You want the soil mix moist to activate the mycorrhizae ( microbial activity) and begin dissolving the powdered ingredients. Every couple of days stir or turnover this mix in the container. Don’t forget to put a lid on the garbage can. You want the containers closed to trap the heat in. Just like a compost it will create its own heat. Now you want to put your container somewhere where it can sit in the sun most of the day and “cook”. You want this organic soil mix to “cook” for at least a month. If this soil-mix turns out to be too hot (powerful) for some reason, just cut it with good bagged organic soil until you get the strength your environment and genetics demands.

This soil-mix is meant to be used along with the spike and layer TLO dynamic, and while it is quite capable of standing alone, it works supernaturally when you add the spike and layering dynamics.

Killer Spike Blends…

Spike #1 vegg
½ cup blood
½ cup steamed bone meal
½ cup high N bat/bird guano
½ cup feather meal
½ cup kelp meal
1 tablespoon ground oyster shell (optional)

Spike #2 all-purpose/flowering
½ cup feather meal
¼ cup bulb food 3-8-8
¼ cup soft rock phosphate
½ cup steamed bone meal
½ cup high P bat/bird guano
½ cup kelp meal
1 tablespoon ground oyster shell (optional)

Moonshine Man’s (Super Soil) !

  1. 1 bag of Ocean Forest
  2. 1 bag of Planting Mix (guano/castings)
  3. 1 bag of Light Warrior
  4. 1 bag of Black Gold
  5. 1 Coco Brick(small brick)
  6. 1 cup peace of mind (for flower)
  7. 2- 5 gal buckets worth of perilte Large grain. 

Moonshine Man says : My only “additives” Id tell anyone to try would be “Fish Mix” from biobizz for a lil boost in veg and Advanced Nutes “Mother Earth Super Tea” for a lil boost on day 25-30 for LARGE plants ……But honestly the mix don’t need nuthin….”

Lumperdawgz’s (Super Soil) !

  1. Sunshine Organic Growers Mix
  2. 25% organic compost
  3. 1 cf. of pumice or rice hulls

Mix this together than add:

  1. 1 cup (per 1 cf.) seed meal or Bloodmeal
  2. 1 cup (per 1 cf.)organic fish bone meal (4-20-0) or Bonemeal
  3. 1.5 cf. of glacial rock dust
  4. 1/4 cup of kelp meal
  5. 1 tablespoon of mycorrhizal fungus to each 5 gallon pot
  6. 1/4 cup of neem seed meal as a top-dressing.

That’s it other than applying aerated compost teas at the beginning of the veg cycle and then again at the beginning of the flower cycle (a high-fungai tea facilitates the take-up of phosphorous).

Slauson’s (Super Soil) !

  1. one bale pro mix bx (3.8 cf) 70% peat moss 30% perlite
  2. one bag coco coir (1.7)
  3. ****{OR one bale of Canadian peat moss (3.8cf) one bag of coco coir (1.7cf) and a bag of perlite (1.7cf) instead of the promix}
  4. two smaller bags of earthworm castings (1.7)
  5. 1 small bag of pumice
  6. 7 cups ff peace of mind or organicare pure
  7. 2.5 cups fast acting pelletized lime
  8. 1.25 cups blood meal
  9. 1.25 cups feather meal
  10. 5 cups fish bone meal
  11. 2.5 cups bulb food
  12. 1.25 cups soft rock phosphate
  13. 2.5 cups kelp meal
  14. 5 cups alfalfa meal
  15. 12 cups steer manure

Slauson says: ” If you can find these and want to add some extras then these are perfect but I don’t find them all mandatory.

  1. 2.5 cups greensand
  2. 5 cups oyster shells
  3. 2.5 cups dolomite lime
  4. 2.5 cups gypsum
  5. 2.5 cups azomite
  6. 2.5 cups epsom salts
  7. 5 cups humic acid ore
  8. 1 cup high nitrogen bat guano

Slauson goes on to say :
“Sprinkle mykos at the bottom of the root hole in each pot.”
“Let cook for 20-30 days or more. Water with chlorine free water and turn every day to every few days. Cooks faster in the sun. Fills up a big kiddie pool. No nutes necessary, just water and a few AACT’s.Once at beginning of veg and once at beginning of flower or every third watering. Teas have ewc, Alaskan humus, alfalfa meal, kelp meal, seaweed extract, fish hydrosylate, humic acid, molasses.”

LC’s  (Super Soil)!

(choose a base option and a nute option and combine)

Base soil: (option 1)

  • 5 parts Canadian Sphagnum Peat or Coir or Pro-Moss
  • 3 parts perlite
  • 2 parts worm castings or mushroom compost or home made compost
  • 2 Tbsp/gal Dolomite Lime

Base soil: (option 2)

  • 6 parts Pro Mix BX or HP / Sunshine Mix (any flavor from #1 up) / Fox Farm Ocean Forest or Light Warrior
  • 2 parts perlite
  • 2 parts earthworm castings
  • 2 Tbsp/gal Dolomite Lime

Nute mix: (option 1)

  • 1 tablespoon Blood meal per gallon or 1/2 cup per cubic foot of soil mix
  • 2 tablespoons Bone meal per gallon or 1 cup per cubic foot of soil mix
  • 1-tablespoon kelp meal per gallon or 1/2 cup per cubic foot of soil mix

Nute mix: (option 2)

  • 1/3C hi N Guano Mexican Bat Guano or Peruvian Seabird Guano (PSG)
  • 1/2C hi P Guano (Jamaican or Indonesian Bat Guano)
  • 1TBS Kelp Meal

The final word! My first choice for growing organic marijuana is Subcool’s super soil. But , that is just because I’m so familiar with using it which makes me a little prejudice. These other mixes of super soil should perform extremely well too. 

Author : Tom D.

Cannabis seeds

65 thoughts on “Subcool’s Super Soil – Improved !

  1. How much does it cost to make a batch of Subcool’s super soil ? The biggest cost here is the base soil. Roots Organics is about $15. a bag. Earthworm castings is the next biggest cost about $11. Bat guano $4, Blood meal $2, Bone meal about $2, Rock Phosphate about $1, Epsom salts, dolomite lime, azomite, and humic acid less than $1 each. Total for a small batch about $36.00 USD. Remember this is used in the bottom half of the pot so a small batch (1 bag) will be good for about 3 seven gallon pots. So about $13. a pot. plus another 3 gallons of base soil on top $4.50 = about $17.50 for a 7 gallon pot. If just using base soil ( a good commercial organic soil such as Roots Organics) for the entire pot, the cost would be about $9. a pot. No fertilizer would be need in veg., but you would have to fertilize in the flowering stage. Super soil may seem expensive but it takes most of the guess work out of fertilizing. I use super soil in the dispensary grow with 600 plants, but at home I use just the base soil and a good organic liquid fertilizer in the flower room for 12 plants. Both ways work very well.

  2. How do you bake super soil when you don’t have sun ? A very good question. You can place the containers of soil in the warmest area you can find. Place the containers near hot lights, near a heating vent, at the hot exhaust coming out of your grow room. In a small room or closet with a small heater on. You will need to invent your own hot box bringing the temperature up to 80-85*F or more. If you have absolutely no way to cook the soil then use water-soluble Mycorrhizae as I have outlined above in the section “No Time To Cook ?” I have used super-soil without cooking, using Mycorrhizae instead with great success on hundreds of plants.

  3. Hi, at what stage of the cannabis plants life would you transplant into the super soil If flowering is started around 12 inches? Do you use the base mix until then?

  4. Howdy David, Interesting question, because few people flower their plants that small. But for whatever reason you are flowering at 12 inches, whether it be for sea of green or height constraints of the flower room, or just because you want to and can, the answer would be the same.

    The short answer is; Super soil is added at the time of transplanting (to the bottom 1/3 to 1/2) of the pot you are going to finish your plant in. If you plan on flowering a plant at that height, a plant should be planted into its finishing container from rooted clone or sprouted feminized seed. When your clone or seedling has developed enough roots and is ready for transplanting will be the time to use super soil in the bottom of the pot you are planting into.

    You will want to flower a 12 inch tall plant in a pot 6 to 8 inches in diameter if no training techniques are performed. If you incorporate training techniques, such as Fimming, Super Cropping, Cutting Back, or a combination of techniques use a pot 8 to 10 inches in diameter. Height of pot should be of similar size.

    Super soil is not usually used in pots smaller than 8 inches in diameter because the ratios of nutrients to soil mass and distribution of those nutrients in relation to the plants roots is not conducive to optimal growth or flowering. For this reason, I would use a good organic base soil and fertilize with liquid organic nutrients for plants flowering in 6 inch diameter pots.

    I hope this answers your question. Tom

  5. Thomas,
    Great article and thank you for this information. I am a bit of a newb at soil grows but I hear that if you can get a super soil to work you will be blown away by the results. Currently I am constrained on my grow room because I am using a grow cabinet that has 3 feet of height and it is 2 feet deep. This is aggravating but it’s all i have to work with right now. I am going to try an auto flower grow since I don’t have much room to work with. What would you say about using sub cool’s mix on an auto grow since auto’s do not like to be transplanted? I am thinking to just use the base mix and a good liquid bloom fertilizer until i have a greater area to grow. Just here to learn and I needed some good advice. Thanks.

  6. Howdy Justin. Super soil always works great as long as it was prepared properly (cooking the mix) and your growing time is sufficiently long enough to utilize the nutrients. (Always keep in mind that super soil “may” need tweaking, depending on the strain being grown.) Super soil is not necessarily any better than a good organic liquid fertilizer. Super soil is just an alternative method of getting nutrients to your plants that eliminates having to fertilize during growing and flowering. With that being said you will just have to experiment to see which method works best for you and the strain being grown.

    I have used Subcool’s super soil on auto flowering cannabis and it works great. I have also never had any problem transplanting any auto flowering strain. However, because your grow is small I would do “exactly” what you are thinking of doing. I would use a good organic base mix, as it will have plenty of nutrients available for vegetating without having to fertilize. When you put your plants into flower I then would use a good organic liquid bloom fertilizer. Good luck and happy growing ! Tom D.

  7. Thanks Thomas. Can you advise on a good area of Colorado to relocate to? My family has already made a ‘one year’ plan to get there. Is it tough to get a job at a legit grow?
    Thanks for the help.

  8. Hey Justin, I live in and like Colorado Springs. Summers and winters are mild here. Cost of living is high and wages are low. Jobs for growers are hard to come by but trimmers are always in demand, expect $10 per hour wage. There are more job opportunities in Denver and many nice places to live in and around Denver. Some people like to say, ” Life is a mountain, not a beach.” Tom D.

  9. Hey Tom,
    Nice read. I am in springs as well.
    I had some left over soil mix from a last summer that i wanted to use, very similar to the base soil that you were using. (2 parts cocoa/3 parts ocean forest.) I folded in a fresh bag of ocean forest along with some new cocoa and mixed in subs recipe about 1/4 strength as recomended just as a test. Super scared as to burn my girls. My question to you is: being as how i let my base mix sit so long i most likely lost quite a bit of certain nutes that were in the soil. Do you think the npk ratio is imballanced enough to stress or cause lockout?.. and do you think sitting so long could have some other adverse affect? Oh and by the way i had it stored in a tight 54 gallon sterolite container and there were no signs of mold or pathagens that i could tell, still smelled like awesome dirt.. Lol

  10. Howdy A-B won, This is a very good question. Does soil loose any nutrients when stored over a period of time? Does soil loose nutrients if stored moist. Will soil loose nutrients if stored and is allowed to dry out? The answer to all of these questions is no. Stored soil will not loose any nutrients moist or dry. One must ask, where would the nutrients go? Nutrients will not evaporate like water does and there is nothing in the stored soil to use up and deplete the nutrients.

    There are only two ways soil can loose nutrients. One way is by a plant using the nutrients, depleting them in time. The other way soil looses nutrients is by leaching. Leaching is watering the soil, letting the water run through it and down the drain. This is equivalent to washing the soil, and will in time wash out the nutrients.

    The reason your soil smelled like awesome dirt is because it is awesome soil. Your stored moist soil is probably better than it was before being stored. The reason? Nutrients in the stored soil were able to break down more by mycorrhizal activity making them more readily available to the plant. If you had stored the soil dry mycorrhizae activity would stop, but the nutrients would remain the same. In this case I would use a water soluble mycorrhizae at the first watering to kick start the process.

    Do not store WET soil. Soil stored wet in a closed container can become sour, and will have a foul odor. This can happen because the soil becomes depleted of air. The organic matter in the soil begins to rot instead of decomposing, turning the soil very acidic. Do not use sour soil and don’t try to correct it as it is a waste of time and effort. Throw it away.

    There is a fine line between moist and wet soil. If your soil smells good it should be fine. If you are concerned that the Ph is off base then I would add dolomite lime to the soil to buffer and balance the Ph. Dolomite lime will never raise the Ph over neutral(7).

    Soil stored in a tight container may be both good and bad. Let your nose tell you if it is good or bad.(how the soil smells). The soil at the top of the container may be just fine and smell good because it has had good air, however soil near the bottom of the container may have gone sour because of the lack of air. This is just something to be aware of and watch out for. This is why moist Super-Soil being cooked should be turned over periodically. Turning over the soil aerates it keeping it sweet. This is also why we turn over a compost heap.

    I do believe your npk ratio should be just fine. Just keep in mind some strains do want a different ratio. The super-soils are a good starting point but may need adjusting for certain strains. I have only had to adjust the recipe for a few strains. Some wanted a little more nitrogen and a few wanted less phosphorus. Just keep a watchful eye and adjust accordingly.

    I hope this answered your question A-B won. Tom D.

  11. Thanks Tom,

    seems like very solid advice.

    I am not new to growing but constantly learning new things every day. I am humble in my persuit of knowledge and try to better my skills and abilities in horticulture by any avenue possible.

    I am never too proud to except criticism, I welcome it however it seems like other growers with vast experience and success are very secretive with their knowledge.. again sir I thank you for the advice and perhaps I may pick your brain about some other topic on growing in the future.

    A-B won kenobi

  12. You’re very welcome A-B one,

    I’m always glade to share information. I may not be the brightest bulb in the box, but I do know a lot. I am also still learning from other growers. Sharing information is where it’s at. My motto; Live and learn and pass it on. Glad I could help. You my pick my brain anytime you want. I may not always have the answer but I will do my best to find the correct answer. Tom D.

  13. Hello again Thomas,
    I have another question about flushing my autos. Keep in mind this is just still a plan as i have not actually grown them yet. So i plan to use a roots organics light mix on some autos. After they veg under a 125 watt cfl they will be under a 400watt hps for flowering. I will use advanced nutrients roots organics flowering juice lightly during the quick flowering cycle. My question is about the flush and the water. I will be using RO water. And I know with RO water I have to add in Cal Mag. When I flush out my plants with water do I still have to use the Cal Mag? It seems like an obvious NO but i just want to make all the right plans. SInce I am using a good soil for veg do I need to add in the Cal Mag for watering during the veg cycle? Thanks again.

  14. Just curious if you have ever used the THC booster that advertises on this page. If so, can you tell about results?

  15. Howdy again Justin,
    Flushing is not really necessary when growing with organics, but with that said I do like to use plain water in the last one to two weeks of flowering. My grows are too large to use RO water for the entire grow so I just use it when cloning. I would use it and do recommend using RO water for the most of entire grow if practical, however I would also use plain tap water between feedings as plants do need a small amount of chlorine. Cal Mag is always good to use during vegetating (but not necessary)and flowering. I would also use a micro-nutrient mixed into the soil when using RO water such as azomite(there are other good choices such as Earth Juice’s Microblast.) When flushing only use plain water. I’m not familiar with Roots Organics Flower Juice and the micro-nutrients in it. Tom D.

  16. Justin,
    I must admit I have not tried the THC Booster, and they have not offered to send me a sample to try out as I believe they should have. I plan on trying it out sometime in the future, but with so many products on the market it is hard to try them all. I realize that is a poor excuse as I should have tried it out before letting them advertise on my site. I am a skeptical of their claims; “Double your yield.”, “50% more THC”. Really ? I find their claims hard to believe and I did notice that they makes no claims using a 1000 watt grow light. Your question is a good one and I have decided to take down their advertising until I have tried their product. Their product may be good, but their claims I find outrageous and unbelievable.

  17. Not to nitpick but mycos and mycos alone stay dormant until contact by spore with root. Since many commercial mycos also contain other soil microbes it’s those that become active in soul but even many of them prefer temps in the high 60s to low 70s. That is why i have never understood the “cooking” part. Plus many commercial mixes also work in symbios with roots. Roots feed microbes and microbes provide solublization and exudates to roots. Highly recommed the book ” Teeming With Microbes”. Many hydro shops now carry it. Also recommend reading Tim Wilson’s page at

  18. Howdy Shawn,
    Your comment needs some more explanation. I am the first to admit I’m not an expert in this field, however microbes do not need to contact a root to become active, or composting could not work and microorganisms are not necessary to make nutrients soluble, or chemical fertilizers could not work. Plant roots do exude a variety of molecules into the rhizosphere, including acids, sugars, polysaccharides and ectoenzymes and this can account for 40% of root carbon. Exudation of these compounds do have various benefits to the plant and to the microorganisms of the rhizosphere. However, I would not go so far as to say roots feed the microorganisms. The cooking of super soil is composting the hard to break down ingredients or the ingredients that generally take a long time to break down at lower temperatures. Cooking speeds up the process of decomposing. I do recommend adding Mycorrhizae to super soil at the time of planting.

  19. Great site my friend!

    Quick question:

    A friend gave me some nice amended soil (not SS) for veg and it has worked great, so great that I’m left with several MASSIVE girls in roughly 10 gal smart pots. I just flipped them a few weeks back, and I’m concerned that they will be needing some nourishment for optimum flowering.

    Can you recommend a few methods to make sure i don’t run into deficiencies during flowering? Top dressing recipes, teas, spikes, etc?


  20. Howdy Ole T,

    I don’t like to top dress plants in a pot because it’s too easy to over do it. Spikes are a definite no, no. I was a nurseryman for over 35 years and never recommended fertilizer spikes for any applications for many reasons. Fertilizer teas are a good way to go. ( The easiest method is a good organic liquid fertilizer (start at half the recommended strength) for blooming plants. Tom D.

  21. I was just checking the ratio’s of the original recipe with the small batch recipe and everything is one eighth of the original recipe except the dolomite and azomite, which is one fourth the original. Is this a mistake (instead of 2 Tbsp dolomite and 1 Tbsp azomite) or is there some reason to use more dolomite and azomite in the small batch recipe?

  22. Hello again Thomas. I’m still trying to just double and triple check everything that I need to ensure a successful grow. I keep coming back to needing more of your advice on the CalMag situation. I am only using Roots Organics soil for my autos. Once they show flower I will hit them one time with a liquid organic fert. The thing I am trying to figure out is if I should use tap water or use RO water. If I use RO water don’t I have to add CalMag? I know you have a;already said that this is not always a must but this is a small grow and there is no room for mess ups. I would think that the plants are getting the Cal and Mag from the soil and the liquid fert. I just have to ask when I can, better safe than sorry. Thanks again Thomas.

  23. Im going to try this subcool super soil using roots organic as my base soil . However i like my OM microbial solution would it be best to not use the OM since roots organics contains mycorrhizae ?

  24. Hello! Wonderful article, very good information! I am new to organic soil, and I still have a lot of research to do, but I am pretty excited to try this Super Soil. Anyway, in another response you said this stuff would not be good for small pots, seedlings or cuttings. What I am confused about is why this is the case, if the super soil is in the bottom layer of the pot the cutting won’t be making contact with the soil until it grows a bit more.
    Maybe I am envisioning it wrong. I do plan on doing a small SoG grow, but I may also revert back to bigger single plants with the scrog method, so I would love to find a way to get this soil working for SoG, just in case I need to revert back to scrogging I will then have my super soil all ready. Do you have any suggestions? Maybe I could cut the super soil with half Roots Organic and use it as directed? I am not opposed to using organic fertilizer but I have to admit, only having to add water to my babies sounds really appealing to me!

    So I’m not quite sure where to go from here. Any suggestions would be great. I know there may not be a universal way to get this working for SoG and larger pots but would love to hear from you or anyone with experience in using super soil in SoG.

    Thanks so much for all the work you put into this article, it is priceless information!

  25. Howdy Rob,
    Very good observation and thanks for checking my math and pointing that out to me. You are right there is no need to use as much as I have posted. 2 Tbsp of dolomite and 1 Tbsp of azomite should be sufficient. I don’t know what I was thinking or why I made that mistake. Fortunately, dolomite lime will never raise the Ph over 7, so using more is ok but a waste of dolomite lime. The same is true with azomite. The plants will only use the micro-nutrients in the amounts that it needs from the azomite. I have corrected the post thanks to you.

  26. Howdy Justin, It’s always good to triple check everything, Just try and not over think everything. Using RO water is always good to use if you can. I recommend fertilizing your flowering plants every time you water them just not once. However, cut the recommended strength to 1/2 the recommended dose. Constant feeding is more natural to the plants. I hate fertilizer instructions that say fertilize every 3 weeks ( or some other similar instructions). They are not taking into consideration how often the plant needs water. What if you only need to water once a week? What if your plants need to be watered twice or maybe three times a week? Plants want a constant supply of nutrients, not just big doses once and a while. Constant feeding is more natural for the plant, but you don’t want to over fertilize, that’s why we cut the dosage in half. Some fertilizers you may want to cut the dose to 1/3. Trial and error is the only way to test what your plants needs. You may want to start with a third of a dose and increase to 1/2 dose.

    With that being said, CalMag is always good to use and you cannot rely on the fertilizer or the soil to supply the magnesium. Between the soil and the fertilizer you will most likely have plenty of Calcium available for your plants. Very rarely is there a calcium deficiency, and it’s hard to overdose with calcium also. I like CalMag but it is not necessary if you use Magnesium Sulfate. In fact Magnesium Sulfate is much more cost effective. Epson Salts(magnesium sulfate)(they are the exact same thing) is very cheap and can be obtained from any drug store. Use two tablespoons for a seven gallon pot at the beginning of the flowering stage, dissolve in water and water your plants with it along with your fertilizer. I would definitely use one or the other. Tom D.

  27. Howdy Ohio T ! Go ahead and use your OM microbial solution. You can never have to much microbial activity. I always add more mycorrhizae to my soil mixes and I recommend you do also. Tom D.

  28. Howdy there Atma! I guess I didn’t explain it well enough, sorry. One should never plant new seedlings or new rooted cuttings into straight Super Soil as that would have a tendency to burn the young plants. This is what is referred to as soil being too hot. It’s not the temperature we are referring to, but as too many available nutrients that can burn the plants leaves.

    The SoG is a different story. Super Soil may be fine in a sea of green, but again it may not. I have not tried Super Soil in a pot smaller than 3 gallons. So I can not say how well it may work. This is what you have to consider or watch out for when using Super Soil in a small pot. When using a 6 inch or one gallon pot and using Super Soil in the bottom third of that pot there may not be enough nutrients to get through an eight week or longer flowering schedule. If you use Super Soil in the bottom half of the pot it could prove to be too much too soon. Experimenting is the only way to tell. Small pots are not as forgiving as large pots are. Tom D.

  29. Thanks Tom for the always helpful advice. I am loving your epsom salt tip, I just want to be clear on the strength. I like to use I gallon jugs. I fill each one gallon jug separately with RO water and then add the nutes. What do you recommend as the the tablespoon amount of epsom salt for a 1 gallon jug of RO water?

    Thanks again.

  30. Hi Tom
    Thank you for the terrific info. I sent you an email but I guess it’s better to keep the conversation flowing here.
    I’m growing in a 3 ft x 3 ft x 6 ft MDF white cabinet, HPS 250 W agro, extractor of 166 cf/m
    I’m using a slightly modified subcool super soil version.
    I have read in many posts that supersoil give lower yield, at least initially, compared to conventional grow (chemical fertilisers).
    Is this true? and how much could be the yield per plant with my little set up? I’m growing indicas (Northern light, kosher kush) and mixed (white widow)

  31. Howdy Daniele, If the super-soil was prepared properly there is no reason for the yield to be lower if all other growing conditions are the same. There are so many factors that effect yield it is hard to even say which factor effects yield the most. Genetics plays the most important roll. I would say then say it’s a toss up between : the size of the plant(bigger the plant -bigger the yield), the brightness and duration of the light(brighter the light- bigger the yield) , the availability of nutrients(proper nutrients bigger the yield), the environment( proper temperature, CO2, air circulation,controlled humidity- bigger the yield), quality of water(proper Ph and maybe Ro water- increases the yield) and growing methods(all methods of manipulation- may increase the yield). My educated wild guess for your yield would be no more than 2oz per plant on a good day, maybe more if there is only one plant in the box. Good Luck, Tom D.

  32. Wow…thanks for all the info….. I’m going for a SOG with 3 or 5 gallon pots…so cost of my media is always on my mind….any tips for reusing my super soil…adding back the notes and the like

  33. When watering during vegetation mode , do you water til you get run off, or do you water just enough to wet the top soil and not get the concentrate soil in the bottom wet,?

    * Another question is: the “improved” recipe of subcool’s super soil calls for Bloom Bat Guano 0-5-0. I was able to only get 0-10-0 (Sunleaves’ Jamaican Bat Guano). I lied, I had a choice of both Jamaican or Indonesian 0-7-0. Im questioning my purchase. Should i have gone with 0-7-0, or should i really use 0-5-0. I think Happy Frog carries a 050.

    and lastly,

    * I fond Humic Acid but in granulated form. is this ok? or should i really use powdered? What about rock phosphate 0-3-0? How does that usually come, the main hydro stores around me didnt carry it, nor did Hope Depot.

    Found it on Amazon by Espoma.…qid=1409115608&sr=1-1&keywords=rock phosphate

    This the same brand i bought my Dolomite Lime in. They are round pellets, the size of peppercorn or bibi gun pellets.

  34. Hey deadave !

    SOG(Sea of Green) with 3-5 gallon pots? That’s huge! Sounds like you’re going after an OOG(Ocean of Green!)LOL I would check your PPM with a run-off test and go from there. I’m not a fan of reusing soil but many folks do it very effectively. I’ve reused soil myself, but when I do I usually change over to an organic liquid fertilizer. Tom D.

  35. Howdy Uriel,

    When watering any plant in a container always water thoroughly and completely making sure all the soil is gets wet. Just because water comes out the bottom of the pot does not mean all the soil got wet. Soil is like a sponge – when it dries out it shrinks. Like a dry sponge pouring water over and thru the soil does not always re-hydrate it immediately. Water will always take the path of least resistance and may come out the bottom of the pot without getting the soil completely wet. If you are not sure if all the soil got wet, put a tray under the pot to catch the runoff water and let the plant sit in the water for an hour. After an hour is up, remove all water left in the tray or risk root rot. If all the water has been absorbed from the tray after an hour repeat the above steps to ensure complete watering. In time you will know your soil and know the best way to water it.

    0-10-0 bat guano is fine to use instead of the 0-5-0, just use half as much.

    Granulated humic acid is will not mix as well as powdered, but is still good. Try and dissolve some in water and see how well it does. If it doesn’t dissolve well either use more of it or put it in an electric coffee or herb grinder and powder your own humic acid.

    Dolomite lime in pellet form really sucks. Try the water dissolve test. I did and it was bad. I could not get it to dissolve hardly at all. I then went to my electric coffee bean grinder and powdered it. You should do the same. Tom D.

  36. Hi Tom
    I’m using a slightly changed SUPERSOIL version in a 250 hps setting, 2x2x6 ft, 3 plants in 4 gals. My T and U are always at about optimal level, almost never above 86F and at 50-60%. I am at day 20 flowering. I flowered when the plants were 12 inches long but i performed early and extreme LST, almost always parallel to soil. The plant had several new branches and did not elongated much after i did LST– started when that were 8 inc at week 3 in veg ended 12 inch with several branches after 40 days from seed. Then I flowered them. Today is day 20 of flowering. There are several tops and buds but I am afraid they are very very small… :-( smaller than what i see in pictures. I can’t figure out what I did wrong. No sign of deciciency, nice color. I started defoliating similar to what you have on the web, with very substantial cutting, to see more development and it helped increasing the number of floweres but not size. Over all I have small plants that not developed much — ww, nl and kosher Kush. What did I do wrong? I water with 0.5 liters every 2 days per plant and that seems enough for them. Maybe the roots have not colonized the whole pot?

  37. Howdy Daniel,

    Lets see what you did. You performed “early and extreme LST methods”. You also incorporated “defoliating with very substantial cutting”. You also only “vegetated for 40 days from seed” only letting the plant grow 12 inches tall before flowering. What did you do wrong?

    Well Daniel, You incorporated too many growing techniques on plants that were too small and never let the plant recover from the manipulation and develop fully. In other words you began the flowering too soon. Keep in mind; The smaller the diameter of the stem and branch the smaller the flower buds will be. When you cut the plant back you increased the bud sites but didn’t give the plant time to increase the diameter of the branch. Cutting back will always increase the bud sites but the sacrifice will always be smaller flowers. I don’t recommend cutting back or Fimming or Super-cropping unless you can let the plant vegetate for another three to four weeks. This allows the plant to grow the remaining branches to a larger diameter. I am also not a fan of defoliating and only recommend that method for the extreme expert.

    You are too far into flowering at this point to do anything else, so go with what you have and your plants will be fine. Just keep this in mind for your next grow. In a 2’x2′ space I would recommend only one nice size plant for best yield and bud size. Sometimes less is more! Good Luck, Tom D.

  38. I want to try this mix both indoor and out door. Planting the outdoor around march-may and indoor, vegging around 4 weeks and flowering 8-9.

    How many weeks of flowering is this supersoil intended for? Or should I say, what is the relationship between to total volume of super soil/super soil:base soil ratio to flowering time?

  39. Howdy Ken,

    Super-soil will be good for up to at least 12 weeks of flowering, for plants in seven gallon pots or larger. 5 gallon pots and smaller may need more than a third of the pot filled with super-soil to last over an 8 week flowering period. Keep in mind Ken, depending on the varieties grown the amount of super-soil used in a pot can be adjusted. Most varieties will want a third of the pot to be super-soil,but some would like 1/2 to 2/3 of the pot filled with super-soil. There are some varieties that will require you to tweak the super-soil recipe. Some varieties will want more nitrogen before the end of flowering and some varieties will want less phosphorus. Keep good notes, and adjust the ingredients for those varieties. The plants will show you what they need. If the plants show premature yellowing – use more nitrogen(blood meal). If the leaves begin to claw, then use less phosphorus(bloom bat guano) next time. These are the only two conditions I have run into using super-soil with over 86 varieties.

    Bottom line, you may have to adjust the ingredients to suit your needs or you may need to adjust the amount of super-soil used in the pot to obtain optimum results. Most varieties will do well using the original recipe and filling the pot only 1/3 full of super-soil, so this is the best starting point. Just remember, keep good notes and adjust as needed. Tom D.

  40. Actually, I think Shaun brought up a good point before about the mycos. Some of the other ingredients in there might be helping to break down your soil but without a plant in there the mycos dont do anything. Mycorrhizae function by latching onto roots. They basically extend the network and nutrient uptake abilities of the roots in exchange for sugars etc. If you want to jump start your soil microbes it would be better/cheaper to just bubble up a handful of quality worm castings with a bit of molasses.

  41. i have green fungus or mold on top of my subcool 35 day old supersoil batch that i was planning on letting cook for 6 weeks total. but now i don’t know what to do. is green fungus the same as white, i mean is it good like the white or is it bad and if it’s bad what should i do?

  42. If I plan on using this mix and when I transplant into a 100gal smart pot, how much subcool super soil would I put in and how much ro soil would I put?

  43. That’s one hell of a large pot. I don’t know why you would want to use such a large pot but be that as it may, Bottom half of pot supper soil, rest of pot, base soil.

  44. Hi Tom, the soil is complete, worms in and seeing great results. How do you run your weekly teas?
    ewt one week and compost teas the next?

  45. Howdy Joseph,
    If you are using Super Soil there is no need for teas, as everything the plant needs is in the soil. You risk over fertilizing and burning your plants using teas or any other nutrients with the “super soil”. That’s the beauty of super soil – nothing else is needed other than light, water and good ventilation along with proper temperatures for growing and flowering.

  46. Hello Thomas,

    I have read that Rock phosphate takes a long time to break down…some estimates are very long indeed with minimum being 2 years….what are your thoughts on this and also do you have an organic alternative in mind?


  47. After putting Super Soil into a garbage can and watering, do you need to check it from time to time to see if has dried and water it again?

  48. Howdy J.Snow,
    Yes you should check it and add water if necessary, however it should not dry out. It’s also a good idea to turn the soil over from time to time.

  49. Uh oh. I just read your reply to Joe D, “That’s one helluva large pot.” Mine are 200 gallons! Don’t ask me why as that was a “better half” decision last year. I do plan on re-using the soil since we have 13 pots and that would be a lot to replenish. This is also an outdoor grow. Now my dilemma is getting the super soil to the bottom of those huge pots! I am going to assume that big of a pot would accommodate 4 plants. If this is so, what do you think of the idea of using a post hole digger to make somewhat bigger holes than the digger itself and filling the holes half way with the SS instead of taking all the soil out? Do you think that would be enough SS for four plants? Or do you have another suggestion? Thank you.

  50. Apparently you plan on starting early and growing all summer. A 200 gallon pot is expecting a 2-3 pound yield. ONE PLANT in ONE POT is the way to go, if you want to do it right. Speaking of doing it the proper way…. Dump all your soil and fill the bottom third to one half of the pot with super soil. More plants in one pot does not equal more yield as they will be too crowded for an all summer grow. This is one of those times where less is more. I hope this isn’t your first grow! If it is I think you and your “better half” have “sugar plums” dancing in your heads. This size of a pot is for experienced growers. Good Luck !!!

  51. I can understand basics of living organic growing their are some questions I cannot find answers to,
    Because a plant needs different amounts and different types of elements within the eco system in the soil from veggitive season to. Look season how then with living organic can you recreate the transition? Irrespective of the lighting times. Because once the soil houses the plant how can you add or subtract certain addatives within the soil to benifit the different stages of plant growth ?

  52. Would using the wicking method of watering be OK with super soil? I’m talking about using a cord or rope to wick water up to the soil as opposed to the other method where the bottom of the soil sits in water all the time.

  53. Hi Tom Im a new organic grower, I like very much the super soil tecnique!! I want to ask you something: how many plants of 15 liters pot can I put under a 600W HPS?
    Thanks for your comments
    Nice web!

  54. hi Tom! been growing with SC super soil for years. I’m I’m maine and its too cold to cook the soil so i put my compost worms in a large shallow tote with the mix and they break everything down in a few months. works great and the worms love it! when i need to use the soil i put some apple slices on the surface and all the worms bunch up under them. i just scoop them back in my worm bin and I’m good to go.

  55. Howdy Steve,
    Although using compost worms is not the same as cooking the soil it is working well for you. Other growers in cold climates should take note ; there is always more than one way to skin a cat. I take my hat off to you for finding a working solution. Congratulations, and thanks for sharing this information.

  56. Hey Rob,
    Wicking can be used however plants should NEVER sit in water for over an hour. Pots should not sit in water, as the wick should be in water but not the pot.

  57. Howdy Mr. Blue,
    When using super soil everything the plant needs, for every stage, in the way of nutrients is already there. The plant knows what it wants and when, and will take up what it needs. The change in the light schedule triggers the plants transition to use different nutrients. You canot subtract nutrients but you can add nutrients if you know the deficency. If you see a magnesium deficiency you can add epsom salts to correct this etc. Growing in super soil is like a plant growing in the wild. Everything is there for the plant and it uses what it needs but with super soil everything is in the correct proportions. This doesn’t mean it’s perfect as some varieties will require tweeking the super soil nutrients. This comes with experience of growing a specific strain.

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