by Nebula Haze
Soil quality is one of the biggest hidden causes of grow problems, and a lot of growers don’t even realize it. Here are some examples.
This grower thought their problem was not enough nutrients because the plant was pale.
But the real problem was the soil. Look closely.
- Thick & muddy – roots can’t get oxygen in soil that’s too thick
- No perlite – these little white “rocks” are key to loose, fluffy soil
- Holds too much water – The soil stays too wet for too long.
Bad cannabis soil can take many forms.
This grower thought he was under-watering the seedlings because the soil looked dry.
But the actual problem was they were growing in low-quality dirt that can’t hold much water.
- Pale – light-colored soil often lacks nutrients and organic matter.
- Solid – this soil is so compacted it’s hard as a rock
- Poor texture – even after adding water, it looks pale and dusty
Don’t set yourself up for failure.
Soil is something you choose before planting a seed, so make sure to set up your grow for success.
Choosing cannabis-friendly soil produces more weed with less effort, because Mother Nature works with you instead of against you. You just need to know what to look for.
Note: Seeds like Purple Haze, Northern Lights #10, Do-Si-Dos germinate strong in any grow medium.
What’s the Best Soil for Weed?
There are many brands that work great. My favorite cannabis soil is Fox Farm Coco Loco soil, which pairs well with Fox Farm soil nutrients.
That’s what I used for this grow journal.
When it comes to growing cannabis in soil, you have 3 main choices to ensure great weed.
- Buy a proven soil – Use a brand known for great cannabis soil. Two great cannabis soil options are Coco Loco potting mix (a coco-fiber-heavy soil mix makes seedlings less prone to overwatering, but needs nutrients earlier) and Ocean Forest soil (true soil that is ”hot” enough you don’t need to add nutrients for several weeks).
- Use locally available soil – Go to a local gardening store and find “organic potting mix” that looks like the soil examples below. Cannabis soil should be brown, rich, fluffy, and ideally already contains little white rocks called perlite. Make sure to give nutrients after just a few weeks, as cannabis plants quickly use up nutrients in regular soil.
- Mix your own soil – If you’re looking to make your own soil, here’s an awesome tutorial by Subcool on making cannabis-friendly soil.
Example of great cannabis soil (this is Coco Loco) – click for closeup
Note about soil & nutrients: Cannabis plants are exceptionally nutrient-hungry as they enter the flowering stage. Bigger plants often use up nutrients in the soil, and need nutrient supplementation right as buds are forming, unless you grow in a big pot with a lot of soil.
You can’t go wrong with the Fox Farm trio for soil. Just follow the instructions on the label at half-strength for cannabis plants. Learn everything about cannabis nutrients & supplements for soil.
Fox Farm trio grows great cannabis in soil.
In addition to Nitrogen, cannabis specifically needs plenty of Phosphorus, Potassium, and micronutrients (a “bloom” nutrient formula) to grow big, dense, potent, and strong-smelling buds.
Give extra “bloom” nutrients as buds form to increase potency, density, and smell.
Weed grown in Coco Loco soil with Fox Farm soil trio nutrients (Candy Games #38 strain).
What should you look for in good cannabis soil?
Weed growers consistently find the best cannabis soil has these characteristics:
- dark and rich
- loose texture
- holds water
- drains well
The following video shows the soil texture you want (this is Coco Loco soil, my personal favorite soil for growing cannabis).
Click here to choose the right soil and learn how to water cannabis plants so they thrive.
When Should I Start Adding Cannabis Nutrients in Soil?
Soil is so simple. So close to nature. Add seeds, remember to water your plants, and wait for an awesome harvest, right?
But cannabis plants typically use up the nutrients in the soil. If you don’t start adding nutrients, the start running into nutrient deficiencies (see what that looks like below).
Once plants get hungry, you can’t go wrong with the Fox Farm trio for soil. For cannabis plants, follow the instructions on the label at half-strength. Get the best cannabis nutrients & supplements for soil.
Fox Farm trio grows great cannabis in soil.
Here’s what you need to watch out for as a soil cannabis grower, so you start adding nutrients before it causes issues.
Pale, lime green cannabis plants in soil = you need to add more nutrients.
If many lower leaves turn yellow and fall off, especially while buds are forming, it’s a sign the plant is “stealing” nutrients from the bottom of the plant to give to the hard-working leaves at the top.
That means if many lower leaves are turning yellow and falling off on their own, you need to add more nutrients.
Add more nutrients if bottom leaves are turning yellow and falling off.
If the bottom of your pot looks like this, the cannabis plant needs more nutrients.
When the Nutrient Problem is Caused by PH
If you see these different symptoms, the cause is likely a pH problem, not needing more nutrients. See pictures of deficiencies caused by pH.
If you see brown spots, or yellow leaves are “stuck” on the plant, it’s likely actually a pH problem.
Another example of a nutrient deficiency caused by incorrect pH.
Healthy Plants Produce Better Harvests
You can still get a great harvest even if you have some nutrient problems. But you get the best cannabis yields and bud quality when plants avoid nutrient deficiencies and get plenty of nutrients while buds are forming.
Fox Farm Coco Loco soil with Fox Farm soil nutrients works well for weed.
Vic’s cannabis plants thriving in Coco Loco soil with Fox Farm soil nutrients.
Which cannabis seeds perform in soil?
You commonly hear soil growers say “soil produces more terpenes”.
So we put it to the test, In our side-by-side grow experiment using super soil vs coco, we found the super soil buds (at least for that grow) had 17% higher terpenes at the lab on average. See the full grow journal.
When terpene production increases, it helps strains express their unique “smell personality”. That means growing strains with strong flavor/smell profiles can help you maximize your soil benefits.
Strains that produce excellent smells in soil
- Sour Diesel – Recently released by Seedsman, this strain has a faster outdoor finish than most Sativa strains. Buds are dense and sticky growing in traditional diesel-smelling “colas” (big baseball bat buds).
- Purple Oreoz F1 – Get the power of an early finishing F1 strain and the smell of fruity dessert. Excellent bud quality and yields. Suitable for commercial grows.
- Guava Root GMO – This indica that thrives indoors or outdoors. Compact grow pattern, high yielding, “rootbeer” smell hints, beginner friendly. Great for extracts (4.7% hash by weight vis ice water extraction).
Bonus: Grease Gun Autoflower is a high-smell strain for autoflower growers.
Purple Oreoz F1 bud basking in the sun last summer.
Grease Gun Autoflower by SkunkSquatch is easy-to-grow with huge smells.
Learn how to HARVEST at the perfect time. Then process your buds to increase density and smell great.
