Best Cheap Grow Medium for Hydroponics

There are at least a dozen different mediums you can use to grow your cannabis plant. Most of them hover around the same price range of approximately $20 per bag. However, the price will depend on how much of that medium you’re looking to buy. There are other important factors to keep in mind, such as the ability to reuse a medium, which would save you money in the long run.

You also want to make sure the growing medium you’re using is effective. If your growing medium is cheap, but doesn’t work properly or causes you issues that could compromise your plant, you’ll likely end up spending more money in the long run.

That’s why we’ve put together this comprehensive list of various growing mediums, which not only gives you an idea of price, but also what you’re getting for that price. Our favourite cheap grow mediums for hydroponics are listed in order of our most to least favourite. At the bottom of each section, you’ll find links to the best mediums in each category, so when you find the right medium for you, you can get started right away. 

Coco Coir

Coco Coir is an increasingly popular medium for hydroponic cannabis growers. Some claim that Coco Coir, which is made from ground coconut husks, is the most effective medium to grow your cannabis in.

The reason why ground coconut husks make for such a good growing medium is because coconuts grow in extremely sunny, tropical regions of the world where they often fall off their trees and into the salty ocean. A coconuts husks are naturally adapted to harsh weather conditions, able to thrive under the hot sun and impervious to salt damage. Therefore, if you use a coconut husk based growing medium, your seed will also have the best natural defence against light and outside conditions. In fact, coconuts themselves use their own husk as a medium to germinate their seeds and grow new coconut trees.

As a hydroponic growing medium, coco coir is hormone rich and free of potentially harmful fungus, making it a safe home for you plant. It also has an optimal air to water ratio, allowing your roots to breathe properly and grow healthily. This material also helps your cannabis seed to successfully germinate, giving them the strongest possible start to their lives. Coco coir is also a renewable resource, meaning it’s good for the environment. Where these coconut husks would normally end up in the trash, or decaying somewhere on land, using them to grow new plants hydroponically gives them a new useful purpose.


  • Mostly organic.
  • Environmentally friendly.
  • Sustainable
  • Renewable.
  • Easily compacted and shipped.


  • Can be easily saturated with water, drowning your plants.


Coco coir is extremely effective and comes at a great value.40L of coco coir can be around $32 USD ($43 CAD)

Coco Coir Best Practices:

  • When growing with coco coir, using a fabric pot will allow for greater airflow, meaning you are more likely to avoid problems of excess moisture.
  • To avoid salt build ups, try using complimentary products such as Canna Coco and Smart Pots, which are designed to work together to optimize the success of your growing medium.

Best Coco Coir for Hydroponics:

1. Canna Coco Brick

CANNA Coco Brick 40l Expandable Natural Plant Medium Soil Substrate, 40 Liter Expanded - 8 Liter Dry, Reusable (1)

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Last update was on: August 9, 2022 9:32 pm
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This high quality 40L brick by Canna rapidly expands due to the special design of the brick. Canna Coco is RHP certified for professional use, guaranteeing a clean product free from potentially harmful organisms. The packaging that this coco coir medium comes in was designed to act as its own growing pot, so you can just open the bag, plant your seed, and add water.

“This is the best coco bar-none.If you can find it locally then …. uh do it. But if you’re like me and no local suppliers carry Canna Coco and you have to buy it online the price is acceptable. Easy to rehydrate, buffered and ready to go. Awesome stuff”
Jason Manuel

2. Canna Coco

CANNA Organic Coco Substrate Bag RHP Certified, 50 L

Last update was on: August 9, 2022 9:32 pm
out of stock

This 50L bag by Canna offers growers the ideal medium for a water/air balance that will keep your plant healthy and strong. Due to Canna’s production process, growers using this medium can be sure they won’t have to deal with detrimental viruses and diseases that can sometimes affect a medium.

“I wanted to give 4 stars because of the price, and sometimes it goes up even more, but the plants and veggies love this medium more than anything Ive used. Comes pretty clean and ready to go. I just flush with about 5.5ph to get a slightly higher soil ph,.. also clean up the loose coco and perlite dust, and go from there. Ive had success re using this coco too, which also slightly justifies the price.”
Shannon Hardy

3. Fox Farms

FoxFarm FX14100 Coco Loco Potting Mix, 2 Cubic Feet, Brown/A

1 used from $35.78
Last update was on: August 9, 2022 9:32 pm
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Fox Farms’ coco coir mixture comes complete with beneficial soil microbes, and mycorrhizal fungi, which helps to strengthen and expand your plants’ root network so that the roots can absorb

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Expanded Clay

Expanded clay is an effective growing medium used by many growers for effective and easy hydroponic home grows. This growing medium consists of many small clay pebbles, which have been heated up using a kiln and expanded into marble-sized little balls. These clay balls are extremely porous and light, making them the perfect consistency for hydroponic systems.

Since expanded clay doesn’t retain water very effectively, this medium is best for growers who frequently water their plants or set up ebb and flow systems.This inability to hold water well makes this medium susceptible to salt accumulation, or drying out if not kept sufficiently wet.

One huge benefit of expanded clay is that it is a growing medium that can be easily reused again and again. This makes them worth the extra money for growers looking to harvest over and over again throughout the year. After harvesting, it’s just recommended that you take out any old roots and sterilize your clay pellets with heat, bleach, or hydrogen peroxide.

Another great aspect of expanded clay is that these pellets do not leach any of their own nutrients into your water, and are also pH neutral, making it easy to get your nutrients and pH levels accurate.


  • A reusable medium, so you don’t have to constantly change your medium.
  • Do not release nutrients into the water
  • pH neutral
  • Great consistency for hydroponic grows


  • Don’t retain water very effectively.
  • Susceptible to salt accumulation and drying out.


Depends on the size of bag you get. 10 Litres will be roughly $18.50 USD ($25 CAD). The most important thing to remember, however, is that expanded clay can be used time and time again. Therefore, one you buy expanded clay pellets once, you don’t have to continuously sink money into buying more medium every time you want to grow a new plant. This is what gives expanded clay such a great value.

Best expanded clay for hydroponics:

1. Grow!t Clay Pebbles

GROW!T GROWT GMC40l, 4mm-16mm, Clay Pebbles, 40 Liter Bag, Brown

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Last update was on: August 9, 2022 9:32 pm
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$63.66 $67.99

These clay pebbles by PLANT !T are 100% natural clay, and come pre-washed. These clay pellets are extremely stable in pH and EC levels. These pellets have great drainage, and work great for drip feed, flood and drain, and multi-pot systems.

“Bag says ‘pre-cleaned’ and I would say that’s true compared to some other brands I’ve bought which left a lot of clay mud and small particles during the cleaning process. This left only brick colored murky water. As others have pointed out, they should be washed before use, at least in hydroponics applications. Put them in a 5 gal bucket with plenty of water, swish them around (toilet plunger is great for this), scoop out with a colander, rinse each scoop full with a hose, and you’re done. Maybe there is some variation during the manufacturer’s bagging process where you could get a batch from ‘the bottom of the barrel’, I don’t know. The size description is accurate. As to those who complain that they float, I say that’s a good thing. After all they are porous and full of air, what did you expect? I doubt if you want the manufacturer to ship them to you pre-soaked with a lot of water – like that soggy compost you get in bags at the hardware, that’s sold by the pound. Plus, where are you putting them that they are floating around? Anyway they will soak up water over time and give your plants the combination of air and moisture that roots need.”
Jamie Lockheart.

2. CZ Expanded Clay Pebbles

Organic Expanded Clay Pebbles Grow Media - Orchids • Hydroponics • Aquaponics • Aquaculture Cz Garden (2 LBS Cz Garden...

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Last update was on: August 9, 2022 9:32 pm
in stock
$13.99 $17.99

Cz Garden Supply’s expanded clay pellets are 100% organic. These pellets offer top-notch aeration, allowing roots to receive enough oxygen to prevent root rot. Also a great product for avoiding soil pests that could otherwise harm your plants.

“Great clay balls. Bag was a bit smaller than I had imagined, but they do what I expected.”
C. Davila-Lohr

3. Hydro Crunch

Hydro Crunch Expanded Clay Growing Media Hydroponic 50 Liter 8 mm Aggregate Pebbles Pellets

Last update was on: August 9, 2022 9:32 pm
in stock

Hydro crunch by Hydroclay offers expanded clay pellets at a fantastic value. These pellets will evenly distribute water and nutrients to your roots, and have above average water retention for clay pellets. Hydro crunch pellets are perfect for hydroponics, and can be re-used time and time again.

“Clay was a little bigger than I expected. However I like the product and price!”
Vanessa M.

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This light, porous, non-soil growing medium is widely used among gardeners, who will often mix this medium into other mediums like soil to increase aeration. The process of creating perlite itself is quite interesting—perlite is the result of air-puffing volcanic glass. The result is a growing medium with one of the best abilities to retain oxygen, which prevents roots from getting over watered and rotting.

Perlite is so light that if you’re using a hydroponic system where the water splashes directly onto your growing medium, the perlite will likely get blasted around your pot. It’s for this reason that perlite is better used in combination with other growing mediums. One of the most popular growing medium mixes is coco coir and perlite. It can also be mixed into soil, vermiculite, or other growing mediums.


  • High oxygen retention
  • Very light
  • Works well in combination with other growing mediums


  • Too easily manipulated by the flow of water due to its light weight.
  • This growing medium is not necessarily great for the environment, as it is created through strip mining.
  • Can be easily inhaled if not careful, as it is extremely small and light.

Perlite Best Practices:

Be careful to keep an eye on your plant’s moisture levels, as this growing medium does not hold water. This growing medium is best combined with other mediums like coco coir.


Depends on the size of bag you get. 8 Litres will be roughly $18.50 USD ($25 CAD).

Best perlite for hydroponics:

1. Black Gold Perlite

Sun GRO Horticulture 1410602.Q08P Black Gold Cactus Mix (8 qt) (2 Pack)

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Last update was on: August 9, 2022 9:32 pm
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This black gold perlite by SunGro Horticulture is great for professional growers, and first time home growers alike. Made in the United States, SunGro’s perlite is sure to be high quality. This product can help to improve drainage and aeration when mixed into other mediums like coco coir. Fantastic medium for rooting clones and starting seeds from scratch.

“I am reviewing such a simple product because previously I bought perlite at the store and it was basically dust, which is quite useless for plantings. This bag included well formed granules and while some of it had been crushed to dust, the majority of the bag was usable and exactly what I needed for my well draining soil.”
Sammy Laxview

2. Hoffman Horticultural Perlite

Hoffman 16504 Horticultural Perlite, 18 Quarts

Last update was on: August 9, 2022 9:32 pm
in stock

Hoffman perlite is all natural, and does exactly what perlite is supposed to: imrpoves the aeration of your medium, improves its drainage, and loosens your soil. Just beware to use a dust mask when using this perlite, as it’s very fine and can be irritating to your throat.

“I got the amount I needed, and at a price that didn’t break the bank. Can’t really do better than that.”
J. Omand

3. ProMix Perlite

Premier Horticulture 0205RG ProMix 2CUFT Veg/Herb - Quantity 1

Free shipping
Last update was on: August 9, 2022 9:32 pm
in stock

This perlite has long been trusted for professional use, dating back to 1968. ProMix is a trusted name that makes a consistently excellent product that will increase drainage and aeration, allowing for healthy roots and an overall healthy plant. This is an excellent, trustworthy brand of perlite, and can be purchased at great value.

“I am not normally a buyer of soil and/or perlite, but you get a pretty decent amount here. Filled a 3 gallon pot with this and a soil mix 40p/60s and I have tons left if I need it.”

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Rockwool is an extremely commonly used medium among hydroponic cannabis growers. Often, rockwool is simply used to germinate seeds in. This medium is created by melting rock—hence the name rockwool—then spinning this melted material into thin, wiry fibres that overlap with each other so that the material can be shaped and compacted (normally into a cube) while still allowing air to move through it.

This growing medium retains water well, and functions fairly similarly to other non-soil mediums. However, rockwool is quickly being phased out by many growers who have been turned on to all the negative aspects of rockwool. First off, rockwool, being made of rock, does not easily decompose. Therefore, once it’s discarded, it will last in its form for virtually forever, unlike materials like coco coir which decompose and give benefit back to the earth. This makes rockwool a bit of an environmental bummer. Rockwool is also a dangerous medium if not handled with care, since it may be covered in excess rock dust that can cause damage to the eyes, throat, lungs, and nose. This is why it’s important to always soak rockwool in water once it’s opened. And in terms of growing, rockwool also has a naturally high pH level, meaning that it will need to be treated before you can successfully grow plants in it. One you start growing, you will still need to keep an extremely close eye on your pH levels, as they will likely fluctuate more with rockwool than other mediums.

Best rockwool for hydroponics

1. Grodan A OK 1×1″ Cubes

This set of 200 rockwool cubes is perfect for the grower who expects to be germinating a high volume of seeds, or trying to grow lots of clones, at once. In each rockwool cube, there is a predrilled hole in the top so you can drop your seed in quickly and easily. This set of rockwool cubes is specifically designed to fit perfectly in a standard, flat growing tray.

“Good stuff for hydroponics. Much easier than starting in soil. Be sure to soak for 30min-1hr in a solution with a pH of about 5.5 or so; this is made with some limestone, which has some basic tendency. Make sure the cubes aren’t saturated either. After soaking the cubes, hold each between a thumb and a finger (a light grip, don’t squish them) and give them a shake or two with a flick of the wrist to achieve an ideal air-to-water ratio. Good product. Easy-to-use and affordably priced. The only disadvantage is that they are not biodegradable so using these cubes for soil purposes isn’t entirely “green”, but they are natural, being made of rock, so that doesn’t bother me too much. I highly recommend for anyone looking for easy propagation or germination of their plants. It’s as easy as soak, place your seeds, put on a heating mat under good light, keep moist, and prepare for healthy seedlings and good roots from said seedlings or cuttings.”

2. Grodan 1.5″ x 1.5″ x 1.5″ Cubes

Grodan Rockwool 1.5" x 1.5" x 1.5" Mini Blocks Pack of 45

Last update was on: August 9, 2022 9:32 pm
in stock
$14.94 $16.55

This 45 piece set of rockwool cubes is more expensive than the 200 piece set, but are also .5 inches larger in size in all dimensions. These cubes are also more uniform, and are robust and durable compared to the smaller cubes.

“So I went outside the usual found a cheaper rockwool cubes and purchased them instead of this brand I’ve always used. Well they sucked big time fell apart when pre-soaked and that’s what I get. Now these here I love and ha e never let me down by collapsing in on itself and EVERYTHING I ha e ever put in this brands cubes has ALWAYS established a very healthy root network system. 💪💪👌👌👍👍 Never again will I stray from the path.”


The price of your rockwool cubes depends on how many you’re buying, and their overall durability. Cheaper cubes may crumble and fall apart more easily. Overall, you can expect to pay somewhere around $20 USD ($26 CAD) for 45 – 200 of these cubes.


  • Easy to plant seeds in
  • Neat and organized material
  • Optimal for growing large numbers of plants at once
  • Retains water well


  • Can be dangerous to inhale the dust that can lay on rockwool, or to get it in the eyes.
  • Not environmentally friendly
  • Naturally high pH level
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Cheap grow medium hydroponics if you’re really strapped for cash


Sand will work for a hydroponic grow, and has been used in the past. But it’s not very common to see a hydroponic cannabis grower using sand today due to its weight and inability to retain water. Sand clumps together, preventing air from getting through. This can have potentially damaging effects to your plant’s roots. If you do decide to use sand, it’s recommended that you use a coarser blend, like builder’s sand.


Gravel has a long history of use for growing plants hydroponically. Since gravel isn’t as fine as a medium like sand, it allows for ore airflow and therefore is fairly effective for cannabis growing. Gravel is also cheap (or free if you know where to look), almost infinitely reusable.

One major downside to gravel, however, is its inability to retain water. It’s also very heavy, especially compared to airy mediums like perlite.

Want to mix your own growing medium? Check out this great video tutorial by nationalparksboard!

Are you looking for the best nutrients to feed your vegging cannabis plant? Read our comprehensive guide to choose the bet nutrients for your plant!

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