The long-time professional medical marijuana grower I look to for “soil” advice makes batches of “supersoil” designed for medical marijuana.
The grower’s code name is GrowDaddy.
We met him in a previous article that focused mostly on his personal strain of landrace Kush crossed with AK-47, which he calls Kush 47. GrowDaddy has been growing cannabis since 1966.
Manufacturing supersoil is one of his main activities, and it takes a hell of a lot of time, experience, materials, sweat and money to do it right.
If he didn’t live in a rural area with several acres of land and ready access to homemade “organic” compost, earthworm castings, manure, and other materials, he’d have a harder time making the rich, sweet, biologically alive supersoil that helps him grow some of the kindest weed I’ve ever smoked, including his one of a kind Kush 47 (AK-47 X 1970s landrace Afghanica), and Mother’s Finest, from Sensi Seeds.
As it is, he sources supersoil materials from commercial and private sources, and devotes about 260 square feet enclosed space to his soil components, mixing, curing and storing.
Yeah you read it right—supersoil has to be “cured.” More on that later.
Before I provide you GrowDaddy’s unique supersoil formula, let’s look at the realities of supersoil versus true hydroponics. When I say “true hydroponics” I mean growing in soilless systems or materials such as rockwool, hydrotron, deep water culture, coco coir, etc.
Some people growing with peat-based mixes such as Sunshine #4 with hydroponics fertilizers call that “hydro” growing.
Compared to growing in supersoil, I guess it’s not so crazy to call that “hydro,” because Sunshine #4, Pro-Mix and similar materials don’t contain a rich percentage of organic elements that feed marijuana crops.
These soil mixes often contain a “starter charge” of nutrients that last a few days. After that you must put hydroponics nutrients in your water because the peat-based mix becomes little more than a neutral substrate.
In that way, this kind of growing has similarity to “true hydroponics” that uses rockwool and other sterile root zone media.
Supersoil mixes can, but don’t always, contain everything your plants need. GrowDaddy used to grow exclusively with supersoil.
Then he grew using supersoil and hydroponics nutrients.
After that, he grew soilless using rockwool, and deep water culture.
He says that when he grew using only supersoil and water, he had to “top dress” a hotter dose of whole mix or P-K elements…a thin layer watered in (perhaps with diatomaceous earth if thrips have been around) from the top of the root zone.
This augmentation top-dress is done about a third of the way through bloom phase, especially for hungry crops such as Kush 47 that go hog wild with feeding during the peak of bloom phase.
Or you can layer your soil so there’s a subterranean layer of P, K, kelp, greensand and other bloom boosting materials lower down in the root zone where your roots are likely to get to and feed off of just as they go into bloom phase.
They can tap into this bloom-targeted layer of nutrients as bloom progresses. This helps plants finish strong in supersoil.
Grow Daddy says he sees especially large buds and fast growth when he’s growing heavy-feeding Kush 47 and other Afghanica-Indica dominant crops grown in diluted supersoil mix and fed a one half-to-three quarter strength hydroponics nutrients program.
He says it’s especially important to provide carbohydrates in grow and bloom phase, and phased bloom boosters timed for the microphases of bloom cycle.
People offer supersoil recipes that suggest a pound of this and a cup of that, or other ways of showing you amounts and ratios of ingredients.
For example, here’s a supersoil recipe from TGA seed breeder and marijuana author Subcool:
8 large bags of a high-quality organic potting soil with coco fiber and mycorrhizae. This is 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
Instead of this type of per pound measurement specification, and based on the art and science I’ve seen GrowDaddy use as he mixes supersoil, I’m using a measurment fomula in which I say “X parts of this and Z parts of that,” so you can make this process work for the amount of soil you need.
Here’s what GrowDaddy recommends:
* Three parts peat-based soil base such as Pro-Mix HP or Sunshine Mix #4.
*Two parts Roots Organic, Fox Farm Ocean Forest or similar organic “whole” soil mix.
* One part aged compost. Don’t use manure compost or fresh compost. Only use compost from an organic source you can trust.
* One part earthworm castings. Again, sourcing and age is important.
* An eighth to one quarter part blood meal, rock phosphate, alfalfa meal, kelp meal, greensand, guano from fruit-eating bats, and steamed bone meal.Go organic whenever possible. A good source for many supersoil components can be found here.
* One eighth to one sixteenth part azomite, Epsom salts, and dolomitic lime. Of these three, the lime is of special importance because it raises soil pH, which is often necessary as a counter to acidic pH that might occur in your raw custom mix.
Adjusting the pH of your supersoil is crucial, whether it needs to be raised or lowered. Soil pH changes over time, so intermittent monitoring is useful.
Try to keep your soil around 6-6.5 pH.
* Two parts large-grain perlite or vermiculite (for drainage).
You may have to adjust this component to ensure easy water pour-through, but you don’t want too much porosity or your mix won’t hold enough water.
The porosity you give your mix depends on your grow room situation, especially your humidity control, how you water (hand-watering versus drip irrigation, for example) and other factors affecting root zone moisture content.
One thing to remember about mixing, amounts of materials, and component ratios: underbuilding is preferable to overbuilding when it comes to supersoil.
If you add too much of one or more of the above components, you can seriously imbalance your supersoil so as to create a toxicity that’s almost impossble to mix out.
In practice, this means you could play it safe by going real heavy on the peat-based soil mix, the Ocean-Forest, and the large-grain vermiculite and perlite, and only add a few small scoops of the rock phosphate, blood meal, guano and other micro-ingredients.
If you underbuild, your supersoil might lack nutrients, but all you need do is use hydroponics nutrients.
If you underbuild, the supersoil won’t be so fertile, but it sure won’t be toxic, and you can easily remediate by supplying water-based nutrition.
But if you overbuild, the supersoil might be too “hot,” and even if you dilute it with peat-based or whole soil mix, it might never be good for your plants.
In fact, GrowDaddy says using a lighter supersoil with hydroponics nutrients gives him his best-quality and heaviest yields.
He says he prefers it to rockwool or deep water culture because it is cheaper and less labor intensive.
Plus, skilled growers can re-use their supersoil for several crop cycles, building healthier, more bioactive soil as time passes.
Mix your supersoil ingredients in a clean, enclosed, climate-controlled area. Lightly moisten the components with a quality compost tea (you can make it yourself or buy it) and let the mix age and cure for at least 30 days if not longer.
After the cure period, test the soil pH to ensure it’s within 5.6-6.4 range. It’s even better to test the mix for its nutrient elements. Have the mix tested by a third-party lab if doing it yourself doesn’t work for you.
Until you get the hang of making supersoil and are confident that your recipe is right for medical marijuana, don’t use it to plant your most valuable clones or seedlings in.
Instead, test it on a few plants that you can afford to lose.
You’re looking to see if it feeds crops from start to finish without you having to use hydroponics nutrients until your plants have been growing for several weeks.
And, watch for nutrient burn. Many beginners, and some long-time medical marijuana growers, may mix their supersoil too hot. This mistake can burn seedlings or weak clones to the ground.
Making and using supersoil is a lot of work and expense, almost as much work and expense as growing in rockwool or some other soilless method and relying only on hydroponics nutrients to feed your plants.
Supersoil proponents claim organic supersoil without synthetic fertilizers produces tastier, smoother and more health-enhancing buds.
GrowDaddy reports that blind tests with marijuana connoisseurs were unable to reliably detect differences in scent, taste, smoothness, or potency when sampling supersoil organic marijuana versus properly-flushed marijuana grown in rockwool and fed only synthetic hydroponics nutrients.
He emphasizes that your medical marijuana plants grow about 10-15% more slowly, and produce 10-25% less harvest weight- when compared to plants grown using premium hydroponics nutrients in a high-ppm soilless system.
“Anybody who tells you they use supersoil and water and get larger or better harvests than if they’re growing with soilless systems and synthetic fertilizers probably didn’t know how to do the hydro correctly,” GrowDaddy says. “There are a lot of benefits to using supersoil, but it always yields less weight than the same plants grown in an optimized hydro system.”
GrowDaddy says one of supersoil’s primary benefits is for beginning growers.
If they at least master making supersoil, they’ll then have an easier time of growing hydroponics marijuana than a beginner who jumps into a tech-heavy system like NFT, aeroponics, deep water culture, etc.
The advantages of growing hydroponics marijuana with supersoil include less time spent watering, and virtually no time spent monitoring and adjusting pH (this assumes you have a quality water supply).
You get a forgiving, more-natural root zone that maintains a “live soil” culture that benefits roots and your overall plant health.
Also, as long as your supersoil is adequately watered, you can leave the garden for more days at a time: supersoil gardens need less feed and irrigation program attention than hydroponics gardens.
And I gotta tell you…playing with rich soil and these other natural materials and minerals is super fun.
I love seeing the different colors, feeling the textures, inhaling the smells (sometimes the smell can be a bit too much), and the art of blending and curing.
It feels good to make supersoil. It’s like a step back in time to when we got our hands dirty growing food outdoors in rich, fertile earth.
GrowDaddy says his best yields and healthiest growing conditions derive from using supersoil and hydroponics nutrients.
The videos accompanying this article will give you plenty of details about making and using supersoil.
Subcool, GrowDaddy and all supersoil marijuana farmers who work with earth minerals, organic soils, and other natural growing methods are carrying on a valuable, time-tested and ecologically-responsible profession.
Growing marijuana this way surely produces superb, high-THC, naturally-produced medical marijuana with direct connection to the power of the earth itself.