5 Natural Nutrients for High-Quality Weed

There is plenty of debate surrounding the best natural gardening practices (and what “natural gardening” even means), but one clear trend is a pivot away from chemically laden, commercially produced fertilizers and plant foods in favor of more natural or DIY solutions like compost tumblers and Bokashi buckets.

Cannabis producers of all sizes have eagerly jumped on this trend. The potency arms race of previous decades has effectively maxed out. With modern extracts regularly approaching the 90-percent THC mark, there is limited value in trying to cultivate yet another slightly stronger cannabis strain. This leaves today’s producers focused on comprehensive quality over mere THC content. This means chasing those ideal terpene profiles, maximizing crop yields while minimizing ecological impact, and finding ethical, sustainable supply chains. Natural soil additives have a role to play in all of that.

It’s not enough to simply throw your food scraps in a compost pile and mix the results with dirt. You need to understand which nutrients your cannabis needs, and how to add them to your soil without introducing other unwanted chemicals, either by producing your own natural nutrients or finding a reputable supplier.

Unless you’re a newcomer to growing (in which case, welcome aboard!) you’re likely already aware of the importance of nitrogen, phosphorus, and potassium, but may not know how to boost or balance these “big three” nutrients through natural means. While nitrogen, in particular, will be a focus of any soil quality project, there are many other nutrients that will impact the growth rate, potency, terpene profile, and overall quality of our beloved buds.

A 2021 study even examined the potential of growing commercial hemp (for biofuels) on lands that had been contaminated with industrial copper. Copper is an essential micronutrient for plants — but it’s also a toxin that degrades cells and impedes photosynthesis. This illustrates a fundamental principle of soil quality management, whether you’re going all-natural or buying plant food at a big box retailer. Just as it is with humans, every medicine becomes a poison at high enough dosage (well, almost every medicine).

Even all-important nitrogen will stress out your plants if used in excess, causing fast-forwarded growth cycles and janky leaf-to-flower ratios in your biomass. As with feeding yourself, the key to soil nutrition is a balance of quality ingredients — not simply cramming your dirt full of as much nitrogen- and phosphorus-rich material as possible. Because, just as we humans are what we eat, your weed plants are quite literally made of the soil you give them to grow in.

Five Key Nutrients for High-Quality Marijuana

Here are five of the elements your plants most crave, and where to source them naturally:

1.Nitrogen

Nitrogen is perhaps the single most important nutrient for cannabis and plants in general. Thankfully, natural forms of plant-friendly nitrogen are abundant. For starters, this is where your year-round composting will start to pay dividends.

The chop-and-drop trimming/mulching method is another extremely easy way to ensure plants are returning nitrogen to the soil for resorption by themselves and future generations. You simply let your fan leaves and other culled plant material decompose atop the soil rather than clean up after your trim. They can be mulched into smaller bits for faster decomposition, but plant matter of all sizes will return to the soil, given time.

When a more significant nutrient injection is in order, blood meal is a top choice for all-natural, nitrogen-forward plant food. “Manure teas” made by diluting manure with water also offer a great boost of nitrogen. Opinions differ on how long a manure tea should “steep” before use, with some recipes calling for 24 hours to activate microbial processes and other methods fermenting a month or more.

A soil test will give you the deepest information about your soil’s shortcomings, but your plants will also tell you when they’re in need. Common signs of nitrogen deficiency include pale, washed-out plants, and an odd root-to-shoot ratio where you get rapid, erratic root growth as the plant searches out nutrients, paired with stunted growth above-ground (due to that same deficiency).

2.Phosphorus

Like nitrogen, phosphorous levels can be boosted naturally with compost or manure. This method presents an issue when you need to increase phosphorus levels specifically in soil that is already nitrogen-rich, however.
Phosphate rock offers a natural solution for boosting phosphorus content without increasing other nutrient levels. Phosphate rock can be found in both sedimentary and igneous deposits. The sedimentary type is more abundant globally and is ideal for agricultural use because it tends to be more easily broken up for distribution throughout soil. Unfortunately for the self-sufficiency crowd, phosphate rock is obtained through mining, so you’ll most likely have to purchase it rather than source your own.

3.Potassium

Plants use potassium to transport water throughout their systems, which aids all sorts of crucial functions like resisting disease, surviving extreme weather, and carrying other nutrients where they’re needed. You can fine tune your composting process to increase potassium by including lots of banana peels and other fruit waste.

Non-compost potassium boosters include wood ash and granite dust, which can often be had for cheap by contacting facilities that burn wood for heat or cooking, and quarries or stonecutters, respectively. Kelp meal also offers a fast, powerful shot of natural potassium, and can be purchased at specialty gardening stores or produced yourself by harvesting, drying, and powdering kelps and seaweeds.

4.Calcium

Healthy organisms of many different types require calcium for critical cellular processes — another thing you and your weed have in common!

Naturally, a favorite calcium supplement for plants is bone meal. It’s widely available at garden supply stores, but ranchers and avid hunters may be capable of sourcing their own. For the rest of us, crushed egg shells make a fine substitute.

5.Sulfur

Your plants need only a trace amount of sulfur to survive, but it is essential for building the amino acids and protein chains that result in strong, resilient plants.

Plants that thrive in nature get all the sulfur they need from the organic material decomposing around them, but this is not always the case in garden and farm settings. Somewhat ironically, reduced air pollution has harmed soil quality in some parts of North America by reducing atmospheric sulfur deposits. Another ironic twist is the fact that sulfur can be used to great effect treating pollutant-contaminated soils. In the copper contamination study referenced earlier, sulfur was added to the soil to make hemp growing viable on the contaminated land.

Growers in need of a natural sulfur boost might benefit most by reducing the levels of phosphorus in the soil rather than seeking a sulfur additive. Excessive phosphorus levels can counteract sulfur and make its benefits unavailable to growing plants.

So where do you start? There are many folk methods for analyzing nutrient deficiencies but ordering a soil test kit is the most reliable method of finding out exactly what your soil lacks. Depending on where you live, a local or regional government agency may also have a mail-in soil testing program available.

Soil Structure: Beyond Nutrient Levels

Andy Ciccone is the creator and host of Poor Prole’s Almanac, a podcast focused on sustainable agriculture and adjacent topics. Ciccone has done a tremendous amount of research into natural gardening methods like Korean Natural Farming, a “hands-off” agriculture philosophy that has been successfully applied to cannabis grows. Ciccone’s audience has seen steady growth alongside the explosion of public interest in natural gardening, and he was kind enough to share some thoughts about developing healthy, all-natural soil for cannabis.

Ciccone pointed out that nutritional soil is also about the structure of the soil, and not just the levels of specific nutrients. Nitrogen and phosphorus levels are undeniably important, but a healthy environment for cannabis growth also depends on the small and microbial life forms present (or prevented from being present) on and around the plant, as well as the physical makeup of the soil: its individual layers and how rocky, sandy, or clay-rich each one is. Ciccone questions why even those of us who are focused on understanding healthy soil and natural, “no-till” methods often fail to apply these practices to indoor and potted grows.

“Think about this,” Ciccone says, “we build the perfect soil mixture for our plants, inoculate it, continue to feed the soil for months on end, including sometimes using a living soil cover.” Then, following our harvest, we “treat the same exact soil life which created our incredible plant as though it were yesterday’s garbage.” While it may seem natural to dump out your used pots once a harvest has been completed, Ciccone sees this as squandering a valuable resource. “We have soil structure and diversity; why aren’t we regrowing in these same pots? We can amend nutrients as much as we need, but we cannot recreate the soil structure with such ease.” Without a consideration for healthy soil structure, all the nutrients in the world won’t save your plants from mediocrity, because nutrient absorption will be stunted by an immature, low quality growing medium.

Natural, Sustainable Nutrient Sources Are Everywhere

Effective soil additives that are free for the taking exist all around us, so long as we’re willing to do the work of collecting them. We would be remiss if we didn’t close by mentioning that human urine is a tremendous natural source of nitrogen, phosphorus, potassium, and trace minerals, not to mention being more than 90 percent water. The pee-pee-plant method of soil maintenance remains understandably dubious to many, but a 2020 study in Environmental Science & Technology has given growers the green (yellow?) light for safely using urine on consumable crops, noting that bacterial concerns can be mitigated by storing the urine under certain conditions prior to use as plant fertilizer.