What Is Biochar & How To Use It In The Cannabis Garden?

Originally published at: https://homegrowncannabisco.com/grow-your-own-with-kyle-kushman/advanced-techniques/biochar-cannabis/

Using biochar is perhaps one of the most revolutionary and sustainable agricultural practice that cannabis cultivators can adapt. Aside from increasing soil fertility and agricultural productivity, it also shows potential in mitigating climate change through carbon sequestration. This approach is nothing short of spectacular in terms of benefits for both the environment and the cannabis plants. Hence, knowing and understanding how to properly integrate its use is the garden is a must.


I always add bio char to my table scrap compost buckets. Then I top them off with urine to the lip. It Make some super rich compost that then loads up the bio char. If you put out unloaded char it will strip your soil of nutrients for a year while it loads. Carbon has 4 bonds so holds on to lots of ions (such as nutrients).

My soil was all ready well loved before I tried bio char. So I wouldn’t say the growth rate changed all that much. But what I did notice was amazing amounts of moisture in my soil (3 10’x20’ raised beds) that I didn’t have before. Specifically instead of watering daily the peak of summer, I can slim it down to once every three days before wilting of my sunleaves. I also notice massive hyphae growth without adding any mycoboost inoculant. The mycorrhizae just envelope the char pieces like it’s candy.

I don’t know how useful it would be an indoor grow unless you carefully reused your soil. By keeping it alive and moist between uses and recycling it the next year. I often Ponder pest introduction reusing indoor soil as well. It’s more a long term thing to build soil than a 1 grow or 1 season soil amendment. Outdoor it is a must.

I get mine by saving the charred logs after family camp fires. :fire:. Then smashing them in the rain with a sledge. It’s too dusty to smash on a sunny day without a mask. Just wait for a good steady rain. I do this actual camping too. If you plan ahead (containers/buckets it messy) you can scavenge the other campsites cold fires for char and end up with significant amounts. It is too expensive to buy washed and bagged unfortunately in my opinion.

Thanks for reading my char party story.
It is a very over looked amendment I cannot recommend enough.

1 Like

Biochar is a great amendment for source of carbon. When using CHARGED Bio-Char in your soil recipe as part of your aeration, use no more than 5% of your total aeration input. This is because too much bio-char can sequester all of the soil’s nutrients and minerals, making them unavailable until the bio-char is broken down.

1 Like

I’m glad I found this thread. I’m contemplating making my own biochar with canna biomass as it seems like to me it would have all the nutrients new cannabis growth would recognize and integrate. Of course, I operate not tied to outcomes and while I will be upset at my crop not turning out, at least I will figure it out. I’ve been reusing some of my soil through my indoor grow, from other plants like marshmallow, calendula, echinacea, and, thankfully, haven’t had any trouble yet. I did treat with #508 so I think it’s helping keep the relationship between water and soil pretty friendly. I’m new to this, so only time and testing will tell.

Thank you for sharing your knowledge and experience, even if I’m just now seeing it.

Hello…I realize this is an old thread…Hopefully you will see it…I’m having trouble wrapping my head around the “charging” the biochar…Urine is an easy way of Charging biochar, am I right ? By recharging, the ph stays neutral…Therefore keeping my soil at a ph 6.4…

@Wildbill yeah. Charging biochar with urine for nitrogen will lower the ph of the biochar. Adding Molasses with the urine will help lower it further as well as helping to charge it with potassium, magnesium, calcium, and other nutrients.