Why grow Cannabis in Organic Soil?
Growing cannabis in organic soil is by the far the simplest, cheapest way to grow cannabis. I grew cannabis non-organically my first couple times and I can tell you 100% it is a big pain in the ass. You'll be buying expensive nutrients and will have to apply those nutes in different amounts on a weekly schedule. You'll have to troubleshoot the leaves of your marijuana plants; Too yellow? Add more nitrogen. Are the leaves turning brown on the edges or are they brown within the leaf borders? That's either a magnesium or calcium deficiency, or maybe it's just the normal aging of the marijuana leaf. Is your pH off? Did you adjust your water with pH Down solution? Uh oh, maybe you should just flush your soil completely because you have a nutrient lockout! If this sounds like madness that's because it is. Expensive madness.
My frustrations and curiosity eventually led me to research 'how to grow cannabis in organic soil'. I read everything I could find online, cut through the crap, and ultimately pulled the trigger on a Compost Tumbler to get the ball rolling. I'm telling you, there's no comparison. For the backyard cannabis gardener, organics is the way to go. Period. It's cheaper and much, much simpler. I'm not joking when I say you just add water and watch them grow.
My frustrations and curiosity eventually led me to research 'how to grow cannabis in organic soil'. I read everything I could find online, cut through the crap, and ultimately pulled the trigger on a Compost Tumbler to get the ball rolling. I'm telling you, there's no comparison. For the backyard cannabis gardener, organics is the way to go. Period. It's cheaper and much, much simpler. I'm not joking when I say you just add water and watch them grow.
How many Cannabis plants should I grow?
I suggest you grow three plants, each in a 5-gallon pot. My goal is to get you to the finish line with one harvested cannabis plant; Three plants allows for accidents or mistakes to happen while still meeting our goal of one harvested plant. I don't recommend growing more than three because if everything works out well (and it should), you might be overwhelmed trying to deal with more than three plants.
Organic Cannabis Gardening: Where do I begin?
The first thing you need to do is get your hands on good compost. Five gallons of compost is enough to make 15 gallons of soil, which can grow 3 sizable cannabis plants. I highly recommend making your own compost as it will be the highest quality and it's free. If you can't make your own homemade compost, you'll need to find a supplier of decent compost or earthworm castings. For now, let me show you how to get started making your own compost for cannabis growing so you can see how easy (and cool) it is.
Shopping for your Organic Soil
You look like a person who just finished making their own compost! Welcome back, now we're going to mix our own organic soil using the compost you just spent the last few months making. Or we can use the compost or earthworm castings you bought. You can mix the compost and earthwork castings too, as long as you have 5 gallons of it and the quality is good. While I've linked you to a bag of EWC that I've used before, I recommend buying your earthworm castings from a local supplier so they are still fresh. Fresh castings still have live eggs inside which hatch new worms. If you're in Southern California, OC Farm Supply will have good AgroWinn castings for you to use and it is where I buy my castings now if I'm low on compost or want a quick nutrient infusion to my soil.
Here is your shopping list for making organic soil. This is the exact list I use. It will make 20+ gallons of organic soil and these supplies will last you a couple years or more. Don't add anything new like Bat Guano or Bone Meal, just keep it simple and stick with the list provided. Alternative brands are fine but please pay attention to my notes so you don't get an incompatible alternative.
Here is your shopping list for making organic soil. This is the exact list I use. It will make 20+ gallons of organic soil and these supplies will last you a couple years or more. Don't add anything new like Bat Guano or Bone Meal, just keep it simple and stick with the list provided. Alternative brands are fine but please pay attention to my notes so you don't get an incompatible alternative.
- Sphagnum Peat Moss, Sunshine brand, 3cuFT. Found at Home Depot for about $13. Required.
- Crab Shell, found on Amazon as Neptune's Harvest Crab Shell 4lb. Required.
- Kelp Meal. Found on Amazon for about $18 as Neptune's Harvest Kelp Meal. You only need the 4lb bag. You can also get Espoma Organic Traditions Kelp Meal if it's cheaper, same thing. Required.
- Tomato-Tone, found at Home Depot or Amazon as Espoma Tomato-tone Organic Fertilizer. You only need the 4lb bag. Costs about $14. Required.
- Dolomite / Garden Lime, found at Home Depot and Amazon for $8 as Espoma Garden Lime (Turns Hydrangeas Pink) 6.75lb bag. DON'T get anything called Hydrated Lime and DON'T get anything with added nutrients. Garden Lime or Dolomite Lime is what you need. Required.
- Rock Dust, found on Amazon for about $18 as Root Naturally Azomite Rock Dust 10lb. You can also find rock dust at OC Farm Supply or any other local Farm Supply. Glacial Rock Dust or Volcanic Rock Dust are preferred since they have the most amount of trace minerals. Required.
- Perlite or Pumice Rock. Perlite is found on Amazon as Espoma Organic Perlite. Make sure you DON'T get Perlite called time-release or with fertilizer added to it. Pumice Rock can be found at OC Farm Supply or any other local Farm Supply. Pumice Rock is cheaper than Perlite. Required.
- Neem Meal (also called Neem Cake), found on Amazon for about $17 called Down to Earth Neem Seed Meal 5lb. Optional but highly recommended for pest control. I used a more expensive version before but now I go with the Amazon version.
- Alfalfa Meal, found at OC Farm Supply or any other local Farm Supply. You can find one on Amazon called Down to Earth Alfalfa Meal for about $10; if I couldn't find generic Alfalfa Meal at OC Farm Supply I would buy this one. Optional but recommended in case your plants are really hungry growers.
- How to Grow Organic Cannabis eBook, found on Amazon for cheap. All the info on this site but easier to follow.
Mixing your Organic Soil
Here's where the fun begins. When I mix my soil, I use a 5-gallon utility bucket ($2 at Home Depot) and a large 20-gallon blue storage tote that I mysteriously acquired over the years and found in the garage. I also have a small 1 gallon utility bucket that I use for my nutrient mix, and I use dishwashing gloves so I don't get my fingernails dirty or torn from the mixing. We're going to mix our soil in single batches of 7.5 gallons (1cuFt) to make all the measurements easy to follow. Since my large blue storage tote has a 20-gallon capacity, it will hold two batches of soil (7.5 gallons + 7.5 gallons = 15 gallons of soil, with an extra 5 gallon capacity to spare). We make only one batch at a time to avoid confusion.
- Take a couple old milk gallons or any other vessel and fill them with water. Let them sit open overnight so the chlorine evaporates.
- Take a sharpie and mark your 5-gallon utility bucket at the halfway mark to indicate 2.5 gallons. For the remaining steps, we will always be filling to the 2.5 gallon mark, never to 5 gallons.
- Fill your bucket with 2.5 gallons of Sphagnum Peat Moss. Dump the SPM into your large storage tote..
- Fill your bucket with 2.5 gallons of Perlite or Pumice Rock (whichever you decided on). Pour this into your large tote with the Sphagnum Peat Moss.
- Fill your bucket with 2.5 gallons of compost. Put on your gloves and do a pass through your compost to remove any twigs, fruit pits, big leaves, or recognizable pieces of food. Eggshells are ok. Please note, if you recognize a lot of food in your compost or if it smells bad, DO NOT use it because it's not finished yet. As noted on the How to make Homemade Compost for Cannabis page, it will take a few months for your compost to break down into a usable state.
- After you've done a final pass through your compost, dump the 2.5 gallons of finished compost into your large tote.
- Add 1 cup of your Dolomite / Garden Lime to the tote mix.
- In a separate small bucket, add the following and mix them together:
- 2 cups Kelp Meal
- 1 cup Neem Meal (if available)
- 1 cup Alfalfa Meal (if available)
- 1 cup Crab Shell
- 1 cup Tomato-tone Organic Fertilizer
- Take 2-3 cups of this nutrient mix and add it to the large tote holding the SPM, Perlite/Pumice and Compost.
- Add 4 cups of your Rock Dust to the large tote.
- Now mix everything in the large tote. Mix it, squeeze it, fold it, after 10 minutes of grunt work you'll notice that the mix is beginning to look like soil. Oh believe me, it's soil alright...incredibly rich organic soil that's gonna grow you some really nice organic cannabis.
- Finally, take the water that you had sitting out and add it slowly to your mix until the soil is damp like a wrung-out sponge. If you haven't let the water sit long enough, no problem just wait until it's ready. If you use the water while it's still highly chlorinated you'll kill off a lot of the microbes that you need to break the nutrients down. It'll take more water than you think, maybe a gallon or more. Make sure you dig down deep into your container to get everything on the bottom up to the top.
- Once you're satisfied that everything has been mixed and moistened, let the soil sit uncovered for a minimum of 4 weeks (the longer the better) while all the microbes break down the crab shell, kelp and other good stuff into a form your cannabis can uptake. You don't need to mix the soil during this time, just make sure it doesn't dry out and add a little water as necessary. Oh, and that seawater smell will go away once the crab shell and kelp get broken down.
- After the minimum 4 weeks has passed, the soil is ready and it's time to Plant a Cannabis Seed. Head on over there now!
I want to thank the person who originally provided these instructions (which I've adapted) and got me started growing cannabis organically. I have no idea who she really is, but InTheGarden on the Grasscity forums was the originator and I'm very grateful that she took the time to post it. I hope all is well with you, whoever and wherever you are, and if you're ever in Southern California please drop me a line so I can buy you some green tea!