In a hydroponics system, our aim is to create a controlled environment for our plants to grow and as part of that, we remove the need for soil as we add just the right amount of nutrients to the water ourselves.
However, soil isn’t just used by plants for nutrients. It’s used for support too – that means we need to provide some support and structure to our plants within our systems. That’s where hydroponic growing media comes in.
In this post you’re going to learn all about growing media, why you need it in your system and some of the best mediums for hydroponics.
Let’s get started!
Why You Need Hydroponic Grow Media
The best way to think about growing media is to think of it as the “soil” in your soil-less system. It traps the oxygen, water and nutrients for your plants and provides a stable structure for the roots to grow through.
11 Best Medium For Hydroponics
Below is an overview of some of the most popular mediums for hydroponics:
We start with Rockwool which has long been a hydroponic gardening favourite. It’s made by melting rock and “spinning” it strands until the final product resembles something much like fibreglass.
Rockwool has started to fall out of favour in recent years as growers opt for more eco-friendly options. The other things to watch out for with Rockwool is that it needs soaking before use due to high pH levels.
Perlite is an extremely light and porous material that’s created by blowing air into volcanic glass. It’s been used by soil gardeners for years to help aeration. Perlite is a great choice for hydroponics due to how much oxygen it can retain.
Depending on your system and plant choice – one thing to watch out for is that as it’s so light, you’ll often need to pair it with another grow medium to ensure it doesn’t wash away.
3. Clay Pellets
While they have fallen out of fashion recently, clay pellets were one of the original choices of hydroponic grow media. Clay pellets are an ideal choice for hydroponics as they provide a stable base for your plants, are pH neutral so release zero nutrients into your system and due to their porous shape provide a good oxygen/water mix for plant roots.
The only downsides really depend on your system. In ebb and flow systems, using clay pellets on a flood table could mean you need added support for the additional weight.
4. Coco Coir
For those looking for an organic, sustainable and effective grow media then look no further than coco coir! This relatively new hydroponic growing media is made from ground-up coconut husks and provides your plants with an incredible medium from which they can grow.
If there is a downside it’s that as the coco coir is so good at retaining water, you do run the risk of drowning your plants, however, with proper management, this shouldn’t be an issue.
5. Sure To Grow
Sure To Grow the brand name of a plastic-based grow media. Within the hydroponic community, it’s been extremely divisive with some growers loving it and constantly singing its praises which in the other camp are those that think it’s overhyped. What we’ve personally found is that it does have some advantages – plant roots to seem to establish quite well with the media. However, I personally like to avoid those grow media that can’t be reused.
6. Starter Plugs
When it comes to starting seeds, along with these LED grow lights, starter plugs are my go-to choice.
Made from organic compost with a biodegradable binding material, starter plugs are really easy to use. You simply place the plugs in trays and your plant roots will naturally grow down to the hole at the bottom.
Pumice is similar to Perlite in that it’s extremely porous and retains a lot of oxygen. However, given how light it is you’ll need to pair it with another media to prevent it from washing away.
Sand is cheap, plentiful and has been used in hydroponics since the dawn of time! While it certainly can be used to grow plants, the thing to consider is that it doesn’t hold water, or nutrients so your plants can become nutrient-depleted fairly quickly.
Aquarium gravel was the very first media that I used when I first got into hydroponics. It’s cheap, easy to clean and drains well so you wont drown your plants. That said, because it drains well it’s not going to be suitable for certain hydroponic systems as it’ll cause your roots to dry out.
10. Brick Shards
Just like gravel, brick shards can be a good grow media. However, as it’s made from crushed up bricks, you’ll need to wash it extremely well to remove all the dust which can alter pH levels within your system.
11. Polystyrene Packing Peanuts
You know those packing peanuts? Well did you know that they can be used in your hydroponics system?
- You can only use the Polystyrene type as biodegradable versions simply turn to mush.
- There’s a real risk that your plants will absorb styrene and become contaminated
- Due to their weight, they only work with certain hydroponic systems.
The Bottom Line
So there you have it, a quick overview of you need hydroponic grow media along with what we consider to be the 11 best medium for hydroponics. Personally I stay away for a number of reasons:
Image by Andrew Gould