Going from traditional soil growing with throw away soils like Fox Farm and Sohum, one of the first differences you will notice is that we use cover crops in no-till soil growing. Cover crops have been used for many years in traditional agriculture. In traditional ag settings it is used to bring nitrogen to the soil, add organic matter back into the soil, as well as help to prep the soil for next season crops by aerating and loosing the soil.
When using no-till soil indoors or outdoors for growing cannabis these same principles apply. If you watch youtube and read blogs you will see everyone talking about how a cover crops primary use is to bring nitrogen back into the soil. This is flat out wrong. The primary use of cover crops in a no-till cannabis growing environment should be to aerate the soil.
What these “experts” tend to leave out is that when used properly a no-till living soil will develop a glut of nitrogen thus negating the need for a nitrogen fixing cover crop. Now there is nothing wrong with choosing a cover crop that will bring nitrogen into the soil, however your main concern, especially as the soil ages, is going to be combating compaction.
As your soil ages the worms, arthropods, microarthropods, fungi, and microbes will work through your soil and break bigger chunks into smaller and smaller pieces. Over time this is where the role of compaction can and will need to be addressed. Maybe not in the first year, or two, but eventually you will need to address this issue for maximum longevity of your soil.
We are all use to seeing things like perlite, pumice, rice hulls, bark, etc.. used as aeration amendments in soil. Traditionally potting soils are used once and then throw away so the longevity of these aeration amendments tend to not be an issue. However, when using no-till soils you want to get the maximum number of years out of your potting soil while still producing top notch crops.
This is where the use of deep rooting cover crops cop into play. We see clover, vetch, rye, etc..., however as your soil ages you need to choose cover crops that will shoot roots all the way to the bottom of the pot, and fill into the sides of the entire container. The problem we see with these traditional cover crops is the “projected” root depth never actually happens in your no-till containers. Clover for instance is “suppose” to grow a root that is up to 2 meters long. Where as in reality they tend to be only a few inches long.
Years ago I sat and thought about this issue. I wondered, if I was going to plant a cannabis plant in the wild where we currently are growing, what would grow next to it? Wild indigenous grasses was the answer. After further research, and a lot of trial and error, I found out that the root depth of these grasses would be something that would actually go all the way to the bottom of the containers, and fill in all sides. After years of using I now have no-till soil that is 5 years old, and I believe that the root system of wild grasses has played a role in that.
The first thing I noticed when using grasses was that when they grow into the container the roots were so deep and wide that you could not pull the grasses out of the container. Also as your cannabis plants grew larger the “die back” was much less with the grasses. They could survive the loss of light much better than other cover crops. This made it so that I don't have to reseed near as often, if ever. Once established, you can run the same cover crop forever essentially.
If you want to apply this same method to your containers or raised beds I suggest you use grasses that would naturally grow in your area. If you are in the foothills of the Rockies then altitude specific grasses need to be used as you can go up to 8500' in some places. Where as if you are in the plains of Oklahoma you should use grasses that have been indigenous to that area for thousands of years.
I won't get into the specifics of what grasses to use as it's up to you to decide what's best for your garden. For a decade I have seen these so called “experts” write blog posts, and make youtube videos and newer growers think what they say is the gospel. This couldn't be further from the truth. All it does is put blinders on the growers so they feel they don't need to research or test any further because this random guy on youtube said “this is the answer.”
This same group of growers is now shipping products thousands of miles because this “expert” said this is the right way to do it. Again with blinders on, this makes it so that you over look resources that could literally be under your nose.
I am not an expert, I never have been. All I did is fuck up so much stuff that I eventually learned from it. That's it. You can do the same thing, and should do the same thing. That's why I suggest testing different cover crops to see how they perform. You very well may find something that works better than grasses, but you have to remove the social media blinders and actually get your hands dirty.