When you want to grow cannabis, deciding the growing medium should be one of the first decisions you make.
Your growing medium is the foundation of your garden.
It goes far in determining what nutrients you feed your plants, how and when you feed them and affects both your yield's quality and quantity.
So let’s find the best growing medium for weed.
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What is a Growing Medium?
Growing medium = A substance or place where your plant’s roots grow and uptake oxygen, water and nutrients.
That sounds pretty simple, but the truth is growing mediums are quite complex.
The Best Growing Medium for Weed
The best thing about picking a growing medium is also the worst thing, and that’s there is no best growing medium.
Look, there are advantages and disadvantages to all of them, and what’s best for one grower doesn’t make it best for you.
So, unfortunately, you have to do a little research.
But what’s awesome is you can pretty much find a growing medium that works needs or restrictions you have.
You can't go wrong with any of the growing mediums as long as you set it up properly.
Picking the wrong growing medium might take a little more work to make it work perfectly.
It's nowhere near as disastrous as picking the wrong grow light or nutrients, though.
These are the factors you'll need to consider when picking your medium:
→ Indoor vs. Outdoor
→ Temperature & Humidity
→ Yield Quantity vs. Quality
→ Initial Cost vs. Long Term Cost
→ Setup and Maintenance
The Three Main Growing Mediums For Cannabis
There are quite a few different growing mediums as you’ll see, but we typically break them down into three main categories:
Soil, Soilless and Hydroponics.
If you're a beginner and not sure which medium is best, we recommend you learn growing with hydroponics.
It is easy to control the nutrients, and can produce a HUGE yield.
Plus, it's usually the most indoor friendly way to grow which is how most people will be growing.
Soil or Compost
When you're looking to grow organically like Ol' Mother Nature intended, soil is without a doubt the best growing medium for weed.
It’s very easy to get started with soil too.
You can buy pre-made soil formulated with nutrients and microorganisms that will feed your plant without you needing to do much work.
This is great for beginners because you don’t have to get caught up on feeding the right ratio of nutrients every day for 3+ months.
This does take some control away.
And it’s not as easy to fix nutrient issues when they happen.
But as long as you buy or make soil for cannabis, you shouldn’t run into frequent nutrient problems like you do with other grow media.
Why You Should Grow With Soil
Most growers agree soil produces bud with better flavor and aroma.
As well, we can’t stress how nice it is that pre-formulated soil makes watering simple, especially if you get adequate rainfall.
You get to just sit back and watch the cannabis grow!
You spend so much time pHing water, locking in the right amount and ratio of nutrients with other mediums but you don’t have to do this with soil.
It’s important to note that you will likely have to recharge your soil medium by adding nutrients yourself when your plants start producing bud.
But there are some super soil recipes out there that don't even need that.
Other Advantages to Soil Growing Medium:
- Great for growing organic cannabis
- Cheap and simple to get started
- Only growing medium that can grow outside without a greenhouse
- Soil allows for temperatures over 77℉ because you do not have to worry about algae that occurs in most hydro systems.
Why You Shouldn’t Grow With Soil
When you want to grow as much cannabis as possible, soil probably isn’t for you.
With a good hydroponic system, pro gardens often see their plants grow 20-30% bigger and faster.
Plus, they get shorter veg and bloom periods, can help plants recover faster, and can use more aggressive training techniques like topping.
Other Disadvantages to Soil Growing Medium:
- You have to make or buy soil that great for growing cannabis
- Wet soil attracts insects
- Super soils can burn young plants temporarily slowing their growth
- Less control vs. other grow media
- Can be the most expensive long-term if you always buy pre-made soil
3 Tips For Growing With Soil
- Soil’s greatest strength is the microorganisms that breakdown organic matter into nutrients and extend your plant’s roots for better nutrient uptake, so learn everything you can about them.
- Soil does well when it can dry out because it helps prevent root rot, so only water after the top inch of the soil is dry — if you pick your pots up often, you’ll get a feel for when they need water.
- We advise that you don’t bring outside soil inside because insect larva and eggs are often found hiding in it.
Soil is where most growers start before switching over to hydroponics.
Creating your own super soil and compost to get the best quality can get more expensive then you think.
Plus, you wouldn't think it but hydroponics uses less water making it more environmentally friendly.
Soilless Mix (Drain-To-Waste Hydroponics)
A soilless medium is simply a medium made up of inert (nutrient-free) non-soil compounds.
It works to support a plant’s roots while retaining enough moisture for it to uptake nutrients from just like soil.
It’s important to note that soilless grow media are commonly used as hydroponic mediums, so you’ll see them used again in our Hydro section below.
The reason you’ll see soilless separated from the hydro is that you can use it as a stand-alone medium that doesn’t require traditional hydroponic equipment: water reservoir, air pumps, etc.
Also, there are a few unique places where you can incorporate growing methods you use in soil, and many growers agree it’s easier to talk about them separately.
There are two big ways a stand-alone soilless medium is like a soil medium:
- First, you will run a drain-to-waste watering system, and this means watering heavily enough that you get 20% runoff every time and you’ll never reuse the water/runoff.
- Second, it looks like you’re growing in soil because most growers hand water and use the same pots and containers that they would with soil.
There are several different soilless potting mixtures you’ll come across:
- Coco Coir: Derived from coconut husks, coco coir is the most popular soilless growing medium, and you can use it as a stand-alone growing medium or mix with another for better aeration.
- Perlite: Amorphous volcanic glass that is frequently used to help improve drainage and aeration in both coco coir and soil.
- Peat (Moss, Reed Sedge, and Humus): Before coco coir, peat moss was the most widely used soilless medium due to its ability to retain a lot of moisture, but now you see it mainly mixed used in hydro setups.
- Rockwool: You often find Rockwool in the form of cubes because they are great for starting seeds, seedlings, and cuttings due to its ability to hold enough water, but still allow for great aeration to build a strong rooting system.
- Vermiculite: A soft and spongy material that’s made from heating mica, vermiculite is better at holding water than perlite and is popular for wetter soils.
- Clay Pellets: With decent water-retention and strong root support, it’s common to find clay pellets in hydroponic systems, but it also makes an excellent stand-alone medium for seedlings and young plants.
If you’re not sure which medium you want to grow with, we suggest pre-buffered coco coir mixed with 20-40% perlite.
You can throw just it in a fabric pot, plant your seed, and be done.
Why You Should Grow With A Soilless Medium
The biggest benefit of a soilless growing medium is its well-roundedness and simplicity.
If you're a beginner, we love the idea of starting with a drain-to-waste soilless setup.
It teaches you aspects of both hydro and soil, so it makes it pretty easy to switch if you ever want to.
Other Advantages to Growing With a Soilless Medium:
- It balances control with ease
- Easy to move the pots and allows for any plant training technique
- Allows you to make more mistakes and they are easier to correct
- When properly aerated, you won't have to worry about algae formation like with other hydroponic systems, and you won't have to worry about root rot seen in soil setups.
Why You Shouldn’t Grow With A Soilless Medium
While a soilless medium is easier, cheaper, and faster to set up, to get the best out of it, you need to water multiple times a day and for most people that means setting up an automatic watering system.
At that point, some growers just end up going with “full hydro” setup.
Other Disadvantages to Growing With a Soilless Medium:
- Bud isn’t as flavorful or aromatic as buds in soil
- Attracts insects more than other hydro systems
- The need for frequent waterings can cause high humidity that threatens mildew and mold
- Drain-to-waste uses a lot of water / not eco-friendly
- Precise nutrient dosages and pH
- Requires a greenhouse when outside as rainwater has too high of a pH value
3 Tips For Growing With Soilless
- Some soilless grow media like coco coir needs to be buffered with extra calcium and magnesium first as it will steal these nutrients away from your plants until it’s been charged — research CEC (cation exchange capacity).
- You can water every other day, but the more you can water the better because salts build up fast and CEC gets messed up, and as a bonus, you won’t need to flush your plants at the beginning or end of bloom — try and water three times daily with runoff every time by flowering.
- Try and match the EC (electric conductivity) or PPM (parts per million) of the water going in that’s coming out — if your runoff ppm isn’t within 100 ppm of the water that’s going in, your feeding is probably off.
When most people think of hydroponics, they imagine a system where the roots are sitting directly in water, but from our last section, we know that’s not true.
Hydroponics essentially means the roots are absorbing nutrients solely through the water you give them.
If you want the biggest yields imaginable, then hydroponics is your answer.
The roots have unadulterated access to nutrients, but this means you need to be precise with the amount you give it or you’ll quickly cause nutrient issues.
And, trust me... you don't want that.
Fortunately, when you know what you’re doing, hydro gives you the best control to fix problems.
When you first start researching hydroponic systems, it’s OK to be scared or feel overwhelmed because there are a lot of different hydroponics system that work in slightly different ways.
But let’s breakdown the most common ones, and we guarantee you’ll feel a lot better about them.
Plus, it will show you how growers incorporate soilless mediums into the hydro setups.
→ DWC (Deep Water Culture)
This is the system most people think of when they think hydro because the roots submerged in the water.
To anchor the plants in place, you use net pots filled with a soilless growing medium.
Clay pellets are a popular choice, so much so that there is a subgroup of DWC setups called bubbleponics.
This is a popular system that’s simple and easy, but you have to watch temperatures in the water reservoir to avoid algae.
→ Continuous Flow Top Feed System (Nutrient Film Technique & Drip)
With nutrient film, your plants sit in a slightly tilted tray that allows nutrient-rich water to flow through the soilless medium, then drop down into the reservoir where a pump will then recirculate the water back up and start the process over again.
A drip system is similar, and the only reason difference is each plant is in its own pot that stands upright allowing water to feed plants from top-down.
These systems save a lot of water due to recirculation, but a pump failure can severely hurt your plants, and you'll use a good amount soilless media because the roots don't sit in water.
→ Ebb and Flow (Flood and Drain)
Remember studying Ancient Egypt in school and how their agriculture thrived due to the Nile periodically flooding their growing fields with nutrient-rich water?
Ebb and flow is the exact same principle, but unlike the systems above, your plants will not have 24/7 access to nutrients.
Your plants still in a tray or pot and the soilless medium is periodically flooded by a reservoir that sits underneath, water will then drain back into the reservoir where it will then be recirculated back up.
Ebb & flow is a great choice for beginners who like DIY because you have a lot of customization available, but you want to watch for roots drying out due to a timer issue.
A new form of hydroponics where the roots are suspended in the air within a light-sealed box or reservoir.
The plants are fed periodically by misting the root zone, and since the roots have more access to oxygen, they may grow faster than in a typical hydro setup like DWC.
The negative here is roots can dry out if the nozzles fail, and this is a more expensive and less-proven setup than the others.
A wick hydroponic system is the oldest known hydro system used in agriculture.
Essentially, you use a material like rope that connects your water reservoir to your plants.
The rope will absorb the water and carry it up to your plants which are planted in a soilless grow media like coco, perlite, or vermiculite.
While the simplest setup, most growers prefer a more complex and efficient hydro system.
Why You Should Grow With Hydroponics
The control over nutrients and ability for your plants to grow bigger and faster is highly desirable to seasoned growers.
Other Advantages to Growing With Hydroponics:
- Uses the least amount of water of any medium making it very eco-friendly
- Lowest risk of an insect invasion or plant diseases
- Once the initial setup is done, many hydro-systems require less work and are very affordable long term.
Why You Shouldn’t Grow With Hydro
Most hydroponic systems require a decent amount of equipment compared to soil or drain-to-waste soilless.
Most hydroponic systems require a reservoir, air pump, air stone, tubing, net pots, and extra timers to control the feeding schedule.
All this equipment can feel like a lot if you’re new to growing and you’ll have to spend more money at first.
Other Disadvantages to Growing with a Hydroponic System:
- Algae can form when temperatures get over 77F
- Equipment failure can spell disaster
- Similar disadvantages as soilless i.e., precision feeding, greenhouse, high humidity, etc.
3 Tips For Growing With Hydroponics
- In hydro, a cannabis plant can recover from topping within a few days, so take advantage and train, train, train your plants.
- Most growers have their water reservoir either in their grow tent or just outside, and since high temperatures are your enemy you want to choose the most energy-efficient light you can afford like an LED as opposed to an HID.
- Timers, air pumps, and other equipment failing is the biggest issue with hydro so don’t skimp on poor quality equipment because it could cost you your entire grow.
Remember, all three growing mediums can grow wonderful weed of all shapes and varieties.
It really comes down to deciding what your limitation are, preferred growing methods, and what you want so let’s recap.
Soil - If you want to grow organically or grow outside without spending a lot of money or time, but want really flavorful weed go with soil.
Hydro - If you’re growing inside, want the most control, want to nab the biggest yields, and have the initial budget for it go with hydroponics.
Soilless - If you are a beginner and not sure which medium is best, go with drain-to-waste soilless because it’s the best of both worlds with it cheap setup like soil but has the ability to deliver big yields like hydro.
What do you think is the best growing medium for weed?
Let us know your favorite in the comments section below!