Now Reading
Greensand and Langbeinite

Greensand and Langbeinite

Greetings and salutations everyone. Today’s article is going to take an overview of a couple mineral packed amendments, greensand and langbeinite. Langbeinite, otherwise known as Sul-Po-Mag, or K-Mag, has long been on my list of things to avoid when gardening in containers. Last year I had a very old organic gardner open my eyes to this element. Since then, I have been experimenting with it quite a bit and will share some cool uses with you.

Greensand is an old-school amendment for reals. Long ago in the early 80’s one of our “secret” combos we would use in holes for outdoor plants, was steer manure and greensand; in the bottoms of the holes. I like greensand a lot, because it obviously works uber well when growing, especially growing cannabis. Yet, science has a hard time pinpointing exactly why it works so well—heh heh—I love that part. I’ll share some awesome greensand stuff as well; let’s roll… 

Langbeinite—The Rundown

Langbeinite from Down to Earth Brand is Awesome

As I stated, I used to absolutely “fear” this stuff (langbeinite/K-Mag/Sul-Po-Mag) in a soil mix, for containers. It’s basically: sulfur (S), magnesium (Mg), and potassium (K). Langbeinite comes in a granular form (Down to Earth brand) with the consistency of very coarse sand—which is a good thing in my book. Cannabis plants really love those three elements a lot, S, Mg, and K. In my TLO soil mix where I used recycled soil, I have now replaced ¼ of my greensand ratios with langbeinite, and it’s working out very well.

Langbeinite is also pH-neutral, wow, I did not expect that one, but the high levels of K buffer it up well, also making it a great element that promotes microlife. The granules are very porous, and this allows microlife to actually use these granules as a “home base” of sorts, much like the oyster shells, or pumice will do. This is a great way to bring sulfur into your mix without causing the soil pH to plummet. Cannabis smells and flavors are inextricably tied to sulfur, per my observations over the years.

Langbeinite is also a great addition to organic teas, in very small amounts. I would add it at a ratio of about 1/8th of a teaspoon per 2-gallons of tea being brewed. You must be cautious using this element, because just a little too much will cause you problems, problems like a K overdose which is a horrible thing that will kill your plants slow and ugly. Locking out K, then N, then P; in my experience. Just watch the PPM of your teas and you’ll be alright.

Greensand—The Rundown

Greensand is Well Worth the Trouble to Get

I can’t say enough good things about this amendment when you add it to your soil mix or compost/vermicompost. First off, if you recycle your soil you really get the most bang for your buck, since greensand lasts a long time, even in high metabolism living soil in containers—like a year I bet. It’s alright to not be recycling and still use greensand in a soil mix, you still get some awesome bennies from it.

Soil structure is greatly enhanced via greensand. Which is a biggie, and while it has something like 30 additional nutrients present besides potassium (K), most of which are micronutrients, it’s a lot about the K, and the iron (Fe). And because you are using living soil, the microlife will make a lot of that K and iron available; even within a month or so. Using high metabolism living soil in containers, I mean.

If you cannot get greensand where you are for some reason, you could substitute good riverbed sand and langbeinite mixed together like 1 teaspoon of langbeinite to every ¼ cup of riverbed sand. The sandy addition to your soil effects the structure of the soil in a very noticeably positive way, along with everything else you’ll notice about your super happy plants.

A Great Soil Goose—Simple Style

First let me say I always add greensand to my stacked worm farm food for my worms. I use about 1 tablespoon of greensand per tray of food, mixed in well. Additionally, I always add greensand and langbeinite to my regular compost as well. The rates to my compost are about ¼ cup greensand and 2 tablespoons of langbeinite, per 2 cubic feet of compost; 2 cubic feet is about 12 gallons of compost.


I hear from some of you that simply cannot recycle your soil, or make compost, or have a worm farm, and you just use good bags of commercial soil in larger container sizes. This little goose I am about to share with you is both very simple, and requires no “cooking” (fast composting) whatsoever, and is highly effective at kicking your production quality; and amounts, upwards. Along with enhancing smells and flavors quite a bit.

I have tested this out on some local small growers, home-growers, during 2018/2019 and the results were always noticeably killer. Cannabis especially loves all the things these two amendments bring. Your bagged soil should be high quality, avoid Sunshine brand (type) bagged soil mixes, as they have too much peat moss in them, but Ocean Forest, or Happy Frog, both by Fox Farm are still all good I believe. So are all the potting soils by G&B brand.

See Also


Per 1 cubic foot of quality commercial bagged soil…

  • Add 3 level tablespoons of greensand
  • Add 1 level tablespoon of langbeinite
  • Add 3 or 4 cups of perlite (optional but highly recommended)

Mix these in well, make sure the soil is somewhat moist, and let it sit in the open exposed to air for 24 hours. That’s it, it is ready to rock and roll! Avoid adding more than I suggest; it may not seem like much but trust me, it is. You can flower plants finishing at 3 feet tall in 4- or 5-gallon containers, under like 300- or 400-watt bulbs, just adding good ground water mostly, running about 70 to 90 PPMs; no chlorine! Truly it is a ‘just add water’ simple tweak with big rewards, when using larger container sizes for flowering. I would go 5- or 7-gallon containers under 1,000-watt lights, and harvest them at more like 4.5 to 5 feet tall.

Of course, I would also always recommend using some TLO style tweaks here, like a top dressing of dry all-purpose organic fertilizer, along with some crab meal too, if possible. Use these on the soil just underneath the shredded bark mulch layer—always mulch! I Hope you all dug the exotic info, my esteemed homeskillets, until next week, Rev out. L8r G8rs.

-REvski ????


Share Skunk Magazine With Your Friends

© 2022 Skunk Magazine. ALL RIGHTS RESERVED.