Last week a Hawaiian aquaponics company that specializes in DIY, raft-based systems sent out a newsletter that had a link to an article that ended with “THESE SYSTEMS DO NOT WORK FOR GROWING MARIJUANA”.  The evidence they used was a report from one of their hydroponic- growing students that tried unsuccessfully to grow marijuana using aquaponics.

Aquaponics Heirloom tomato

Aquaponics Heirloom tomato

This started me thinking about a few things. Is there a limit to what you can grow in aquaponics? First, because medical marijuana is legal with a permit in Colorado, it is an unavoidable topic of conversation here.  I admit I have a tremendous curiosity about how well marijuana would grow in an aquaponics system, especially since every other plant I’ve encountered grows so vigorously.  No, I don’t use marijuana nor have I ever grown it, but I have no judgment about those who do.  I think that many are doing tremendous humanitarian work with medical patients and marijuana.  Plus, who am I to say that my Friday Happy Hour martini is any worse than someone else’s joint?  But my real curiosity is with the plant itself…

Aquaponics peppers in 3 colors

Aquaponics peppers in 3 colors

I think that the statement above about the plant not growing in “these systems” may be true.  But this is because the referenced system is raft based.  I have become convinced from my experience, conversations, and research that raft based systems, while absolutely the best for commercial operations growing lettuces, greens and herbs, don’t offer the robust nutrient mix that a mature media based system offers.

Think about it.  The engine of an aquaponics system is what I have started calling “the conversion team” of beneficial nitrifying bacteria and composting red worms.  The bacteria convert the main, liquid source of  waste from the fish into food for the plants and reside on all moist surfaces of an aquaponics system.  Which system has more surface area –a raft-based system where bacteria reside on the underside of the raft itself, as well as the sidewalls and the plumbing, or in a media-based system with sidewalls, plumbing, and 12” of gravel, expanded shale or Hydroton?  My vote is for the media based system.

Then you have the solid waste, which provide additional micro and macro nutrients for the plants.  In raft-based systems, the solids are filtered out and removed as unwanted waste.  In media-based systems, the solids remain in the grow bed and are digested by composting red worms that return it to the system ecology as incredibly nutritious vermicompost.

Travis Hughey aquaponics systems melon

Travis Hughey's aquaponic systems hanging melon

Adding further fuel to my conviction that there just isn’t anything that can’t be grown in a mature media-based aquaponics system, I recently had the delightful pleasure of interviewing Travis Hughey. He is the inventor of the Barrel-ponics™ system and the father of that movement in the U.S. I interviewed him for an article I’m writing for BackYard Aquaponics Magazine. While we never discussed marijuana specifically, Travis agrees that he has yet to find a plant that won’t grow well in media-based aquaponics.

So can marijuana be grown in aquaponics?  I sure don’t see why not.  While it is a very special and obviously controversial plant, it is still just a plant.  I’m willing to bet that there are people out there who are trying to grow marijuana using aquaponics and probably succeeding mightily.

Let me know what you think.