17 Best Hydroponic Growing Medium (2020)
Cheers for finally starting hydroponics gardening! You’ve got yourself the best grow lights and a clean nice space for your new seedlings. But let me guess why you’re here. Everything’s going well except that you haven’t figured out the best hydroponic growing medium to use. Am I right?
I know that finding the best hydroponic growing medium is pretty frustrating because you have so many choices. For example, you’ve got perlites, rockwool, and peat moss, among many others. So, which one should you get?
The thing is, the best hydroponic growing medium should provide physical stability to your plants. Besides that, it needs to serve as a buffer for moisture and nutrients. Not to mention, it needs to drain water well! These things are all essential to keeping your hydroponic plants healthy.
So before you head out to get one, here’s a treat for you! I’ve just made a review of the best hydroponic growing medium you’ll ever need. Whatever hydroponic systems you’re using, this article has just what you’re looking for. So, keep on reading!
You can also check out this video where I show the grow mediums that I use in my hydroponics setup.
Table of Contents
Quick Overview of the Best Hydroponic Growing Medium (in no particular order)
Rockwool
1.5″ Rockwool Starter Plugs, 2 Sheets of 49 Plugs (98 Plugs Total) + Twin Canaries Chart
Expanded Clay Pellets
GROW!T GMC40l – 4mm-16mm Clay Pebbles, Brown, (40 Liter Bag) – Made from 100% Natural Clay
Sand
(5 Pounds) Natural Decorative Real Sand – Beige – for use in Crafts, Decor, Vase Filler, Aquariums and More!
Oasis Cubes
Oasis Horticubes ES Grow Cubes 276ct Sheet Multi Seed Dibble – Biodegradable Oasis Cubes (3)
Peat Moss
Hoffman 15503 Canadian Sphagnum Peat Moss, 10 Quarts (10 Quarts 1 Pack)
Rapid Rooter Plugs
General Hydroponics HGC714135 Rapid Rooter Plant Starters, 50 Plugs, Black
Rice Hulls
Rice Hulls – Organic Use – 5lb – House Plants – Gardening – Chicken Bedding Nesting
Biostrate Hydroponic Mats
Biostrate Hydroponic Growing Mats – 1 Roll – 9″ by 120′ – for Hydroponic Grow Systems – Sure Biodegradable Felt Pads to Grow Microgreens, Wheatgrfass, Baby Salad Greens
In-Depth Reviews of the
Best Hydroponic Growing Medium
Interested in knowing why they landed on the best hydroponic growing medium? Great! This part discusses each of their unique characteristics. Besides that, I also included the downsides and upsides when using them. Hence, it’s easier to find one that’ll fit your growing needs.
Rockwool
If you’re looking for a good growing medium to germinate your seeds, then Rockwool is the way to go!
This is by far my most favorite growing medium ever. In fact, I’ve used it as the base medium for my net pots with a little help of clay pellets on top.
What is it?
In case you’re wondering, companies manufacture Rockwool from basalt rocks. They melt these rocks at extremely high temperature then after, spin them up to create fibers. Not to mention, you can buy them in cubes and different sizes.
Preparation
You’ll love that its preparation is a breeze. Just cut up the cubes and soak them in water with a pH of 5.5. You’re free to add a tiny amount of nutrient solution if you want to. Based on experience, you’ll see that it’ll soak up all the goodness in about 30 seconds. Then, you can now transfer them to a grow tray. Easy, right?
Pros
- It can hold up 5 times its weight. Talk about great water-holding capacity!
- Ideal for fast-growing plants as it has internal air packets
- Lightweight and absorbent
- Applicable to potted plants and grow beds
Cons
- Non-biodegradable
- Potential hazard so wear a dust mask
- Has a high pH so I suggest you use an adjuster
Expanded Clay Pellets
I think you’ll agree that overwatering is one of our worst nightmares. And if you add up clogging filters to the equation, then we are officially having the worst day, my friend.
Luckily for us, expanded clay pellets are here to save the day.
What is it?
Manufacturers bake these natural, clay pellets in over 2,000 degrees Fahrenheit. Hence, it’s porous and reusable!
Preparation
It’s pretty easy to prepare, too!
The most important step is to thoroughly rinse these bad boys out. You’ll never know — there might still be some residue in the bag. If not rinsed, these residues may clog up your filters and drainages.
Some growers would tell you to soak them in water with pH 5.5 or in hydroponic nutrients with pH 6. But I’d tell you not to bother with that as this has a neutral pH.
Pros
- Can hold air bubbles
- Lightweight
- Renewable, reusable, and environment-friendly
- Perfect for flood and drain and deep water culture systems
- Neutral pH
Cons
- Low water-holding capacity
- Residues may clog up filters and drainages. So, rinse them well!
Coco Coir
Trying to find a more sustainable and environment-friendly growing medium? Then Coco Coir is for you!
What is it?
It’s true what they say, “Looks can be deceiving.” This growing medium looks like soil! But the truth is, manufacturers just pick the outer husks of coconut shells. Then, they dry them up and turn them into this amazing growing medium. Hence, you’re sure that it’s renewable and organic!
Preparation
Now, here’s the tricky part. Depending on what brand you’re buying from, always get a coco coir that has low salt content. I also suggest buying it in bricks form as it’s cheaper.
If you decide to buy coco coir bricks, then the first thing you need to do is to rehydrate it. What I usually do is just throw it into a bucket of water and wait until it expands. I kid you not, this might take a while but it’s going to be worth it in the end!
Pros
- Renewable, organic, and environment-friendly
- Looks and works like soil
- Lightweight and very absorbent
Cons
- May have a high salt content
- Has potassium so I suggest you only use coco coir-specific hydroponic nutrients
- Has extremely high water-holding capacity that may drown your plants. Hence, I suggest you mix some perlites to improve drainage
Gravel
Let’s admit it. Expanded clay pellets can be quite expensive. Good thing, gravel can serve as an alternative to clay pellets. I find that it works well in drip and flood systems!
What is it?
Need I say more? You can see landscapers use them as decorations. This is the main reason why many growers don’t use it in hydroponics. But hey, it works, especially if you’re having budget constraints!
Preparation
Like with clay pellets, make sure you rinse them well to avoid clogging of drainages and filters.
Pros
- Widely-available and incredibly cheap
- Ideal for drip and flood systems
- Improves drainage
Cons
- No water-holding capacity. But you can always mix it up with a highly absorbent medium to make up for this lacking
- Non-biodegradable
Perlite
Ever been curious about the white specks you usually see in potting mixes? Oops, your kids are wrong—- that’s not popcorn! Rather it’s Perlite, the best hydroponic growing medium for rooting cuttings!
What is it?
Perlite is a volcanic rock with high moisture content hence, making it non-renewable. Manufacturers heat the rocks up and because of its moisture content, it puffs up like popcorn! Cool, right?
Preparation
You’ll love that this doesn’t need that much preparation. But I need to mention that this is perfect for root cutting. Just dip your cuttings into rooting hormones and complete the rest of the propagation process. After that, prop it to your net pots with perlites.
Pros
- Ideal for rooting cuttings
- Widely-available and incredibly cheap
- Lightweight and porous
- Improves aeration and drainage
Cons
- Low water-holding capacity
- Non-renewable
- Potential hazard so wear a dust mask
Sand
Believe it or not, sand hydroponics is a thing. And surprisingly enough, it’s fast becoming a favorite of those who are into deep water culture systems.
What is it?
Sand doesn’t need that much introduction. It’s widely available and inexpensive! Couple this with a good hydroponics system, it can provide water retention and root aeration. It has a neutral pH, too.
Preparation
Just a caveat though, using sand as a growing medium might take a lot of work.
For one, you need to prepare an EPIC (Environmentally Passive Integrated Chamber) with holes at the bottom. Then, you put a layer of gravel then pour sand on top. I kid you not, this design works like magic! Sand absorbs the water from the bottom while allowing your plants to grow their roots all the way down. Talk about an effective way to achieve deep rooting!
Pros
- Widely-available and inexpensive
- Ideal for deep watering/ deep rooting
Cons
- Preparation takes a lot of work
- Heavy when wet
- Low water-holding capacity
Sawdust
Those who say sawdusts are just dirt have been missing out on this amazing growing medium. Don’t ever think of disposing of them!
What is it?
Sawdusts are a by-product of woodworks like drilling and sawing, hence the name! It’s absorbent and lightweight— perfect for hydroponics gardening.
Preparation
Remember that when working with sawdust, it steals away nitrogen from your plants. So, I suggest only using this as a medium when planting mushrooms.
Pros
- Widely-available and inexpensive. You can even get it for free!
- Absorbent and lightweight
- An ideal medium for mushrooms
- Organic and environment-friendly
Cons
- Poor drainage system
- Steals nitrogen away from your plants
Soilless mixes
Admit it. Sometimes you don’t have the time and budget to mix and match mediums to suit your growing needs. Good thing, you can always buy soilless mixes!
What is it?
Soilless mixes comprise of fibrous material and aggregates, such as coco coir, perlites, and pumice. This combination ensures that your medium is a perfect buffer for moisture, nutrients, and air.
Preparation
The good news is this doesn’t need that much preparation unless you’re using peat moss-based soilless potting mixes! Peat moss has a high pH so you might need to adjust your solution’s pH. Hence, I suggest you buy pH neutral coco-coir-based potting mixes instead.
Pros
- Widely-available and inexpensive
- Absorbent and lightweight
- Serves as a perfect buffer for moisture, nutrients, and air
Cons
- Some are highly absorbent so I suggest adding up some perlites or pumice
- Has no nutrients
Oasis Cubes
Looking for a biodegradable alternative to Rockwool? Then, check out Oasis Cubes. It’s so easy-to-use and only takes a minute to prepare!
What is it?
Oasis cube is a water-absorbent foam. Some growers call it Phenolic Foam or Floral Foam but seriously, they all work the same. It’s lightweight and has little capillaries that absorb moisture and provide oxygenation.
Preparation
You’ll love that it just takes a minute to prepare this.
Firstly, pour a little amount of nutrient solution into a deep tray of purified drinking water. Oh, and before I forget to mention, make sure the mixture has a low EC. Then, dip the oasis cubes into the mixture for 30 seconds. Then, pull it up and drain. After that, fill up each hole with seeds. Voila! You can now continue the whole propagation process.
Pros
- Absorbent and lightweight
- Ideal for starting seeds and propagation
- Biodegradable in 18-24 months
Cons
- Not ideal for transplanting
- Not reusable
- Pricey
Peat Moss
I’m sure you’re already familiar with this. But in case you aren’t, Peat Moss looks and works like soil. But don’t fret, it is a sterile soilless medium you shouldn’t miss trying!
What is it?
Peat moss happens when sphagnum moss and a few organic materials decompose in peat bogs, hence the name! Besides that, it has a dark color and a fibrous texture, similar to coco coir.
Preparation
Luckily for you, it doesn’t need that much preparation. You just have to moisten them a little before placing them into seedling trays. Then, continue the propagation process. Also, remember to spray some nutrients solution over your seedlings!
Pros
- Absorbent and lightweight
- Has a low pH (acidic) so your acid-loving plants will be happy with this
- Ideal for starting seeds and propagation
- Organic
Cons
- Non-renewable
- Has a low pH (acidic) so it may not be an ideal medium for alkaline-loving plants
- Has no nutrients
Rapid Rooter Pugs
No questions asked. Rapid Rooter Plug is the best growing medium for starting seeds. Let me give you a hint: it only takes three days to get your seeds sprouting! Don’t believe me yet?
What is it?
You’ll love that these plugs have general hydroponic nutrients in them. This ensures that your seeds grow fast and happy! In case you’re wondering, Rapid Rooter Plugs usually consist of peat moss and some binders. Hence, you’re sure your seeds are getting enough air, moisture, and nutrients.
Preparation
Rapid Rooter Plugs definitely live up to its name! This is because preparation only takes a minute or two.
Just go ahead and place them in a bucket of water. Here’s an important part: squeeze, then drop your hand to the bottom of the bucket, then release. You can see it expanding, that’s when you know it’s ready to go into the trays.
Pros
- Has a general hydroponic nutrient solution
- Ideal for starting seeds and propagation
- Absorbent and lightweight
- Has internal air packets
Cons
- Non-renewable
- Has a low pH (acidic) so it may not be an ideal medium for alkaline-loving plants
Growstones
Here comes the tough competitor of expanded clay pellets! If you find that clay pellets don’t work out for you, then Growstone is a must-try.
What is it?
Surprise! Growstones aren’t stones, rather they’re pure glass. Hence, you’re sure it’s reusable and environment-friendly. Besides that, it comes in different sizes and shapes. As if that’s not enough, it can also hold equal amounts of air and water! Cool, right?
Preparation
Here comes the tricky part. Firstly, you need to rinse growstones to remove their silica coating. Another thing you need to do is to soak them in water for 24 hours to balance the pH level.
Pros
- Can hold both air and water
- Reusable and environment-friendly
- Ideal for deep water culture
- Lightweight
Cons
- Potential hazard because of its silica coating so wear a mask and rinse it well
- pH level may rise because growstone uses calcium carbonate as a foaming agent. So, I suggest you regularly check the pH level and adjust, if necessary.
Rice Hulls
Gone were the days when people consider rice hulls as “wastes”. They’re fast becoming the best growing medium alternative to perlite!
What is it?
As you know, rice hulls are a by-product of milling rice grains, hence the name. Not to mention, unlike perlites, these are organic, renewable, and environment-friendly!
Preparation
Here comes the tricky part. Avoid using fresh rice hulls because they’re prone to fungi and bacteria which we don’t want our plants to get. So, I suggest buying parboiled rice hulls (PRH) as these are sterile and free of spores and bacteria. If you can’t buy one, then you can do your own by steaming and drying the rice hulls.
Pros
- Renewable, organic, and environment-friendly
- Lightweight
- Has an overall pH of 5.7 to 6.5 which is close to neutral
- A good addition to potting soil mixes
Cons
- Prone to fungi and bacteria if the manufacturer did not properly sterilize them
- May break down over time
Pumice
Many growers are now considering pumice over perlite. And I can’t blame them as this works as well in improving aeration and drainage for your plants.
What is it?
Like perlite, this is volcanic material. But instead of heating it like what manufacturers do with perlite, they crush pumice into small pieces. It also comes in different shapes and sizes. Not to mention, it’s pretty lightweight, too!
Preparation
Like perlites, this doesn’t need much preparation. Just make sure you rinse them well to avoid residues clogging up filters and drainages.
Pros
- Lightweight
- Improves aeration and drainage
- A good addition to potting soil mixes
Cons
- Non- biodegradable
- Some might be too lightweight for deep water culture so I suggest buying bigger pumice stones
Polystyrene Packing Peanuts
Yes, you read it right! Those white packing peanuts your pets love to play with deserves a spotlight on the best growing medium list. But why?
What is it?
These are just your standard packing peanuts. They’re incredibly cheap. In fact, you might already have some of these at home. Not to mention, they’re lightweight and drain water well that’s why some growers use them as a growing medium.
Preparation
What’s cool about packing peanuts is that you can use them right away. Since this also improves aeration and drainage, you may substitute heavier stones like gravel to this.
Pros
- Lightweight
- Incredibly cheap or you can even get it for free
- Reusable
- Improves aeration and drainage
Cons
- Non- biodegradable
- Potential hazard as plants may absorb polystyrene from this material
Vermiculite
I’m pretty sure you’ve heard many growers compare this with perlite. But, there’s so much more you need to know about Vermiculite!
What is it?
Like with perlites, manufacturers make vermiculites by heating them, then letting them expand into pebbles. What’s cool about this is that it has better water holding capacity than perlite. Not to mention, it effectively retains nutrients for later use!
Preparation
Like with other stones, just remember to rinse them well so that residues won’t clog drainages or filters.
Pros
- Lightweight
- High water holding and cation exchange capacity
- Improves aeration and drainage
- Suitable for soilless mixes
Cons
- Non- renewable
- Might clog drainages and filters if not rinsed well
Biostrate Hydroponic Mat
There’s no way I will forget to review the best growing medium for microgreens. If you’re into growing nutritious pea shoots, radish sprouts, and sunflower shoots, then I suggest you give this a try!
What is it?
Biostrate Hydroponic Mat is another breakthrough in hydroponics gardening. It’s a bio-based textile that effectively absorbs and retains moisture. It’s thin and lightweight— perfect for planting microgreens and even wheatgrass.
Preparation
I kid you not, this is so easy to use. Just give it a quick mist or dip it into the water with nutrients then quickly place seeds on it. After that, give it another round of quick mist. Easy, right?
Pros
- Lightweight
- Ideal for microgreens and wheatgrass
- High water holding capacity
- pH neutral
Cons
- Takes a long time to break down
- Only works for microgreens
Frequently Asked Questions about the Best Hydroponic Growing Medium
Haven’t figured out what to get? No worries, I’ve answered some of your most sought-out questions about growing mediums to help you out!
Q1. What is the best hydroponic growing medium?
As mentioned, the best hydroponic growing medium that you should use must be able to satisfy these three things. Firstly, they must provide physical stability to your plants. Secondly, they need to serve as a buffer for moisture and nutrients. Thirdly, they need to drain water well. Rockwool is the best all-round choice for most hydroponic systems.
If you look back to the list earlier, I’ve provided a lot of options for all these criteria.
Personally, I find that the best growing medium for my plants is not just one. Rather, it’s a combination of two or more complementing mediums. For instance, I need the buffering capacity of Rockwool so I will use it as my first choice of medium. But if I find that its drainage capacity is lacking, I add a few clay pellets in. That’s the trick!
Q2. How to make a hydroponic growing medium?
Unfortunately, I don’t think you can make vermiculite and perlite at home, can you? But here’s what I’m sure of: you can mix and match some mediums to fit your hydroponic system. The trick is to always mix up aggregates like gravel, pumice, perlites to fibrous materials like peat moss.
Q3. How to make a hydroponic solution at home?
I kid you not, it’s so easy to prepare hydroponic solutions at home. You just need to mix three amazing products from General Hydroponics. Luckily for you, I’ve made a video on how to do this. Check it out!
Conclusion
Finding the best hydroponic growing medium can be confusing but I hope this article has helped you. Good thing, the growing mediums that I listed here are easy to find. In fact, they’re also available online. If you found the great hydroponic medium but unsure what to plant you can check out this blog where I listed some of the best plants for your hydroponics setup.
So, which one’s your favorite growing medium? I’d love to hear your thoughts in the comments section.
Also, don’t forget to check other blogs from Rudd’s Home Farm to learn more tips and tricks on hydroponics gardening.
