For those who cultivate cannabis (or any plants for that matter), it’s often a necessity. Plants need to be fertilized to thrive as regular soil doesn’t typically provide the nutrition required for optimal growth. Can plants live without fertilizer? Sure – lots of gardeners do without it. But soil loses its fertility as time goes by. A great harvest one year does not guarantee the same outcome the next. Instead, plants absorb the nutrients the soil once had, requiring you to replenish with fertilizer if you want your plants to blossom to their potential.

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Chemical Fertilizers: Less Than Ideal

Chemical fertilizers are commonly used for plants. They’re effective short-term solutions but diminish natural soil fertility in the long run. They also allow lots of rooms for error (applying incorrectly can leave the plants burned). The frequency of which you have to fertilize also tends to increase; fertilizer is like a fix as plants want more and more.  If your crops are already affected by certain diseases, chemicals can make things worse.

When it comes to cannabis specifically, these types of fertilizers can leave the weed tasting artificial. This ruins the experience of many.

Natural Fertilizers Are The Way To Go

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The cons of chemical fertilizers have left many in the marijuana industry looking for alternative solutions to fertilizing. Some of these include:


Guano is a fancy name for “bat crap.” It’s extremely high in nitrogen, phosphorus, and salt, making it a good choice for fertilizing. Among the talents of this poo are soil conditioning, soil enrichment, improvement of drainage and texture, and compost activation.  It’s also fast acting, a natural fungicide, and it can be used prior to planting or during an active growth phase. Though it’s feces, it isn’t strong smelling. You can buy it from various places online.

Background photo of Bat Guano Fertilizer iStock / sasimoto

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If you compost, you’re already collecting fertilizer. In fact, you can use your compost to make compost tea. Compost tea is made by using well-finished compost (compost that is broken down already). Ignore the banana peel you freshly discarded and dig down deep into the compost bin.  Then, take the following steps:

  • Fill a bucket one-third of the way with finished compost
  • Add water to fill bucket
  • Let mixture sit for a few days, stirring on occasion
  • Drain with a cheesecloth or an old towel
  • Dilute with water
  • Spray it on your plants

Fish Meal

Fish meal is fish ground up into a fine powder. It works as a fertilizer by pushing up nitrogen from the soil. When you couple it with fish emulsion (the fluid remains of fish), the emulsion prolongs the release of the nutrients. Fish meal can attract some predators, especially bears. If you grow in an area known for bear sightings, you might want to rethink your fertilizer choice, or at least get a bigger fence. 


Looking for an organic fertilizer? Well, “urine” luck. Urine, when fresh, is high in nitrogen, with moderate levels of phosphorus. It works as a liquid fertilizer or as a compost accelerator. Does this mean you should bypass the indoor plumbing and simply use your marijuana to do your business? No. Urine is potent and, as a result, should be diluted before application. Waiting too long to use it can also present the risk of ammonia levels spiking.


vermicompost with worms iStock / KalebKroetsch

Vermicompost happens when worms take over your composting duties. It’s a mixture of decomposing fruits and veggies, bedding materials, and the feces of red wigglers, white worms, and other earthworms. It contains water-soluble nutrients and acts as a soil conditioner. It’s a mainstay in organic farming.

In fact, of all organic fertilizer, it’s worm castings that are getting the most traction; some people believe they’re the best fertilizer available for cannabis growers. Why? Because worm castings shorten the germination cycle for new plants, increase yield, and protect the plant from disease. They’re very affordable as well, even if you don’t have a pet worm that you’ve trained to have a bowel movement on cue.

Not everyone is down with organic fertilizer (or organic anything for that matter), but if you’re worried about what chemicals are doing to your plants, to your lungs, to your finished product, or the Mother Earth, the above offers some natural solutions.