by Nebula Haze
Intro to Growing Cannabis in Soil
First-time growers often start by growing cannabis in soil. If you’ve grown other plants in soil and/or have maintained a soil garden, this may be the best choice for you because you will already be familiar with a lot of what you need to understand to grow cannabis in soil.
Soil-grown cannabis looks and smells amazing!
Buds grown in soil tend to have a stronger, more complex smell.
Soil Pros for Growing Cannabis
Many Already Have Soil Experience – Growing cannabis in soil is similar to growing plants like tomatoes or corn – soil growing may be the most intuitive option for you, especially if you already have gardening experience.
Simple – hand-water your plants in containers.
Outdoor Growing – most outdoor growers choose to grow with soil. In the wild, cannabis grows in soil, so growing outdoors in soil is most like a cannabis plant’s natural environment. Many people find that when growing cannabis outdoors, soil is the simplest and most intuitive way to grow. Growing with composted “super soil” gives the grower the ability to grow outside without needing to add synthetic bottled nutrients or manage the pH of the soil.
Option 1: Store-Bought Soil + Nutrients (info below) – Growers can buy soil online or at a store, and simply add nutrients throughout their grow while watering for thriving, happy cannabis plants.
Option 2: Compost or Purchase “Super Soil” – For those who don’t want to worry about soil pH or adding nutrients throughout the grow, there is the option of amending and composting your own super soil (or buying it already composted) specifically made for cannabis plants. While this option takes more time before you start growing, it can be somewhat simpler especially for those who have composted soil in the past.
Note: Some growers believe growing in organic composted super soil with a rich microbial life can actually improve the taste and smell of cannabis by causing a plant to produce higher levels of terpenes and terpenoids.
Soil Cons for Growing Cannabis
Pests – Soil is an organic material, and there are many types of bugs that can live in soil. Often, soil-growers seem to suffer more often from pests attacking their plants than hydroponic growers. Learn about cannabis-friendly pesticides.
Slower Growth – Growing in soil is not as fast as growing in a soilless or hydroponic setup – hydroponic plants tend to get faster growth rates, especially in the vegetative stage. However, speed isn’t everything when it comes to growing weed!
Marijuana Soil Setup (Which Soil & Nutrients?)
Get Soil and a Container for Your Cannabis Plants
- Common cannabis soil mixes include:
- Fox Farms Happy Frog – Light soil mix that doesn’t contain a lot of nutrients, so you should start adding nutrients almost immediately. A good choice for growers that want more control over the nutrients they give their plants.
- Fox Farms Ocean Forest – “Hot” soil mix that contains a lot of nutrients. You shouldn’t add any extra nutrients for several weeks after plants are given fresh Ocean Forest soil. It’s possible that young seedlings may get a little nutrient burn at first, but they will grow out of it quickly.
- “Just Add Water” Soil – If you add super soil concentrate to the bottom of your plant pots, you often don’t need to add nutrients as the plants will slowly “dip into” the extra nutrients as needed.
- Any high-quality organic soil mix will do in a pinch. If it looks like the soil below, you’re good.
- Avoid Miracle-Gro soil or anything with chemical “extended-release” nutrients!
- To improve drainage, it can be beneficial to add 10-20% perlite to aerate and loosen soil. However, if you start with a cannabis-friendly soil mix like Happy Frog or Ocean forest, the soil already contains all the perlite you need. That’s what those little white rocks are in the picture below.
- Common cannabis containers include classic plastic pots, terracotta pots, smart pots (fabric pots) and air-pots (plastic “air-pruning” pots). Learn more about different types of containers.
Soil growing probably requires the least effort of any growing method (especially if growing in “just add water” super soil). Your main effort will be spent watering your plants.
This is what excellent soil for growing cannabis should look like. Rich but loose and airy.
This is Ocean Forest soil, which cannabis plants love.
Not sure which soil should you start with? I recommend starting with Fox Farms Happy Frog soil for a perfect cannabis soil starting mix. For the easiest soil growing, get a smart pot (a growing container made out of fabric – they work perfectly for growing cannabis). Then use soil-friendly cannabis nutrients like Fox Farm Soil trio.
Don’t want to use nutrients? Learn how to mix up your own super soil so it has all the nutrients your cannabis plants will need! Bonus: With composted super soil made using the recipe in the link above, you don’t need to worry about maintaining your pH! your super soil will automatically manage the pH for you.
Learn the basics of growing cannabis.
Avoid Miracle-Gro! Do not use “Miracle-Gro” soil or any soil that has “extended-release” nutrients for growing cannabis. Learn more at the bottom of this article. These types of soil will continue to release nitrogen to your plant roots for up to 6 months. This can cause deficiencies or burn your cannabis plants in the flowering/budding stage, reducing your overall bud yields. I have seen growers successively grow cannabis in Miracle-Gro, but many of them struggled with nutrient problems in the flowering stage.
Cannabis-Friendly Soil Nutrient Suggestions
For new nutrients you haven’t grown with before, always start at half-strength and raise the amount slowly. Do not use nutrients with every watering! Most growers will add nutrients every other watering or even less frequently. Remember, a little bit goes a long way. You can always add more nutrients later, but it’s a lot more difficult to take them back from the soil.
An easy and simple nutrient system for beginning cannabis soil growers is the Fox Farms Nutrient Trio for Soil. The Fox Farms trio works great for growing any cannabis strain, without needing any additional supplements. Learn more below.
Be aware there is a soil version because Fox Farms offers a hydroponic version of the same nutrient line. Though in my experience the hydroponic version also works just as well in soil 🙂
IMPORTANT: Root pH Affects How Well Your Cannabis Absorbs Nutrients!
You can grow monster cannabis plants if you give good soil, good nutrients, and tons of light.
Nutrient Picks for Growing in Soil
- Fox Farms Nutrient Trio for Soil <– Very concentrated, less is more. “Grow Big” & “Tiger Bloom” provide most of the major nutrients your cannabis needs, while “Big Bloom” has many micro nutrients and beneficial compounds that help nutrient uptake and root health. This trio works extremely well by itself, just follow the feeding schedule (here’s a PDF, here’s a JPG) from Fox Farms. They offer a lot of supplements, but the only bottles you need to be successful growing cannabis is the FF trio, which is highlighted in green on the schedule. The trio tends to be strong, so use it sparingly (especially “Grow Big” & “Tiger Bloom”). I recommend giving plain pH’ed water every other watering to make sure your plants only get exactly what they need.
- Botanicare Pure Blend Soil Grow & Soil Bloom (Use Grow for the Vegetative Stage and Bloom for the Flowering Stage) <– Recommended for Beginners because this nutrient system is easy to use, relatively cheap, and can be found at almost any hydro store or online. Botanicare Pure Blend for Soil works great for growing any cannabis strain, without needing a lot of extra care, or any additional supplements. The two bottles are all that’s needed to get your plants successfully to harvest time. You can follow the instructions on the bottle or use the feeding schedule from Botanicare (here’s a PDF, here’s a JPG). They offer a lot of supplements, but the only bottles you need to be successful growing cannabis is the Pure Blend 2-pack, which is what’s reflected in the “standard” version of their schedule. Repeat “Week 3” of the Vegetative part of their schedule until the end of the vegetative stage if it lasts longer than 3 weeks. For auto-flowering strains – skip week 3 of “Vegetative” & skip week 6-7 of “Flowering/Fruiting” – otherwise you can follow the instructions almost exactly.
- Dyna-Gro (Foliage-Pro, Bloom) <– Cheapest nutrients that still work great for growing cannabis in soil. Use “Foliage-Pro” during the vegetative stage, and “Bloom” during the flowering stage. Just follow the instructions on the bottles!
- HydroOrganics Earth Juice Nutrients (Grow, Bloom). Optionally you can add the following supplements: Earth Juice Catalyst, Meta-K, & MicroBlast (use Hygrozyme as needed for roots) <– From a grower: “Earth juice Grow/Bloom is organic stuff, veddy potent and cheap.”
Follow the Earth Juice nutrient schedule used by Endive in his 9.3 oz LED grow journal.
This nutrient schedule was used to grow the following buds under a 250W LED.
- House & Garden Line-up (expensive yet remarkably effective) Soil A + B, Roots Excelurator, Algen Extract, Bud XL, shooting powder. <– Get a custom nutrient schedule directly from the people at House & Garden via their free online nutrient calculator. From a grower: “H&G was started by a top researcher from Canna. They are right outside of Amsterdam and because cannabis is legal there, so both Canna and H&G are able to do R&D using cannabis. I don’t know about Canna, but I know that House and Garden makes all their own nutrients in-house and they work great.”
This plant was grown using the House & Garden Line-up listed above. Learn more about House & Garden nutrients for growing cannabis!
- Don’t want to use nutrients? Learn how to use “just add water” super soil so your soil has all the nutrients your plants need! Bonus: With composted super soil, you don’t need to worry about maintaining your pH! Instead, you are actually creating a specially made microbial soil mix that will automatically take care of the pH for your plants, while slowly feeding them the exact nutrients they need.
Maintenance Cost – After setup, the main maintenance will be replacing your soil every grow (highly recommended – reused soil often does not get great results even with added nutrients). Occasionally you will have to replace used containers that crack or break. You also need to think about the cost of electricity and replacing nutrients every few grows.
Maintenance Effort – Watering your plants, providing nutrients and managing the pH to prevent deficiencies (composted super soil has microorganisms in it to help manage pH and make nutrients available to your plant roots).
How long until harvest? Soil has relatively slower growth rates than hydroponic methods, but a tuned-in soil grow can achieve impressive growth rates if given a great environment and plenty of bright light. Most soil grows require 1-3 months of vegetative time (depending on how big you want your plants) plus 2-3 months of flowering/budding (depending on your strain).
Learn more about how long it takes to grow cannabis here.
Happy cannabis plants in soil
Many growers feel that cannabis grown in organic super soil has the best smell/taste profile, though this is highly disputed among hydroponic growers 🙂
How long can grower be away? It’s important for a grower to always remain close by for their first grow, especially for inexperienced growers. Experienced growers can safely spend more time away from the garden.
Bigger containers hold more water and therefore give growers more time away, since constant watering isn’t needed. In the best-case scenario, it is always best to check on your plants at least once a day. You never know when a pest infestation will take hold, a plant will fall over, or some other unexpected event will happen.
How to Grow Cannabis in 10 Steps
Tips to Preventing Common Seedling Problems
Most Common Soil Mistake: Overwatering
The most common mistake made by beginners growing cannabis in soil is they water their plants too often. Overwatering is almost never a case of giving your plants too much water at once. Instead, overwatering cannabis in soil is almost always caused by giving the plant water too often.
Are my cannabis seedlings overwatered?
5 Surprising Signs of Overwatering
Overwatered cannabis plants appear droopy or have deficiencies.
Here’s an example watering schedule for seedlings in 2, 3, or 5-gallon fabric pots for first 30 days. Your seedling may need more or less water depending on the temperature, humidity, and how strong the grow light, but many growers have asked for a simple schedule to get an idea of what they’re aiming for.
- Day 1 – Give 1 cup (250ml) water per plant
- Day 3 – Give 2 cups (500ml) water per plant (wait 3 days after this one since you just upped it)
- Day 6 – Give 2 cups (500ml) water per plant
- Day 8 – Give 3 cups (750ml) water per plant (every 3 days after this)
- Day 11 – Give 3 cups (750ml) water per plant
- Day 14 – Give 4 cups (1 liter) water per plant
- Day 17 – Give 4 cups (1 liter) water per plant
- Day 20 – Give 5 cups (1.25 liter) water per plant
- Day 23 – Give 6 cups (1.5 liter) water per plant
- Day 26 – Give 6 cups (1.5 liter) water per plant
- Day 29 – Give 8 cups or 1/2 gallon (2 liter) water per plant
- Continue giving 1/2 gallon (2 liters) per plant every 3 days (more or less often as needed)
How to water cannabis plants in soil
Wait until the top of your soil feels dry up to your first knuckle (about an inch deep). If you try to pick up the plant, it should feel light. A heavy pot means there’s still lots of water inside.
Add nutrients to your water (if needed), then adjust the pH. The most common reason growers get nutrient deficiencies is because they don’t adjust the pH of their water. Most soil growers only add nutrients every other watering (or even less often), but even when giving just plain water you still need to adjust the pH of your water to prevent deficiencies.
Water your plants and keep adding water until you see at least 20% extra runoff water drain out the bottom of your pot. Go back to step 1.
Ready to start growing cannabis in soil?
10-Step Guide to Growing Cannabis
Example of a cannabis soil grow from beginning to end.
Don’t Use Miracle-Gro or Other “Slow Release” Soils!
Say “No” to Miracle-Gro soil for growing cannabis!
Many of us have seen Miracle-Gro used around our homes, so we know that it works for ‘regular houseplants’. Cannabis is just a tough weed, so Miracle-Gro nutrients should work great for it, too… right?
No. Not really. Well kinda.
Standard Miracle-Gro nutrients (their all-purpose plant food) will work “just okay” for the vegetative stage of your plant’s growth, but anything with Miracle-Gro in it is a terrible choice for the flowering stage due to its high levels of Nitrogen. Using standard Miracle-Gro nutrients in the flowering stage will cause your buds to grow smaller than they could have, and they may possibly have a chemical taste from nutrient buildup in the plant tissue.
However, the real problem is Miracle-Gro’s “time-released” soil (or any type of extended-release spikes or soils that aren’t organic) which slowly release Miracle-Gro nutrients over the course of several months. These types of soil continue providing Nitrogen slowly throughout your plant’s life. That means your plant won’t be able to use up all the Nitrogen in the vegetative stage as it would with regular soil, again giving you the problem of too much Nitrogen in the flowering stage.
Basically, avoid giving your plants a lot of Nitrogen in the flowering stage! Anything that does that is not a good idea 🙂
Jump to…
Complete Basics Guide: Learn How to Grow Cannabis
Soil vs Hydro? Which is better for growing weed indoors?
