What is Growing Media & How to Prepare it

What is growing media and how do I prepare it for my plants? How do I know which growing media to start with when I’ve never grown plants before? These are the kind of questions new growers may ask when first starting out. If you want to get stuck into growing plants for the first time but don’t know where to begin, then start here! This blog s provides info on what growing media are, their different natural properties, and what they offer your plants.

What is a Growing Medium?

First things first, what is growing media? Put simply, a growing medium is any substance used to grow plants in. Growing media either naturally contains, or has added to it, the elements, vitamins, minerals, and microorganisms required by plants to thrive.

More information on these nutritional components of growing media can be found in the next section: ‘How do I Prepare my Growing Media for Planting?’.

For now, all you need to know is that there are two types of media— living and inert.

What is the Difference Between Living and Inert Growing Media?

Living media is any type of growing media which naturally contains all the elements, vitamins, minerals, and microorganisms required for the substrate to support plant life. This typically refers to soil and soil-based substrates.

When growing plants in living media, it is the substrate itself which is fed when nutrients are added. These nutrients are absorbed and used to fuel the microbiome of the soil or soil-based substrate, therefore keeping it alive. The absorbed nutrients are then broken down by the biochemical processes of the substrate and microorganisms living within it. This makes the nutrients more easily absorbed by the plants’ root networks. In return, the plant will fuel the living media with biochemical byproducts such as sugars.

Inert growing media are chemically neutral, providing no nutritional value to plants. They primarily function as a support system for the root network, while allowing the free flow of water and plant nutrients.

Plants growing in inert media feed directly on the water and nutrients which pass through it. Inert media only holds onto as much nutrient as the substrate can absorb, and plants will absorb as much of the nutrient as they need. Therefore, the rest of the nutrient solution will either run off as waste product or return to the nutrient tank (depending on your set-up).

Which Substrate is Right for My Plants?

The growing media you choose to use will depend on the kind of environment your plants prefer.

The two main growing media that most people have heard of are soil and coconut husk (also referred to as coco). Plant Magic offers several media products using these substrates in varying combinations.

What are Coco and Coco-Based Media?

Coco is simply ground-up coconut husk. In its purest form, coconut husk is high in salts, which can be damaging to the root network and impact plant growth. Additionally, coconut husk may contain various types of impurities, such as harmful bacteria or fungi. To remove these impurities and make the coconut husk suitable as a growing media, it undergoes various treatments. For example, the coco used in all Plant Magic media products is buffered with a calcium-magnesium solution to remove excess salts and reduce the media’s EC value.

Once treated, the coco is often used as a substitute for traditional peat media. Compared to most peat-based media, coco is more sustainable because peat is a finite natural resource which takes centuries to form— 1 metre of peat can take up to 1,000 years to form. Coco is also naturally bacterial and fungal-resistant and lasts longer in soil than peat-based composts.

So, now we know what coco is… What is a coco-based media? Put simply, it is any growing media containing a high percentage of coco substrate.

This type of growing media is well known for being highly absorbent, as it can retain up to ten times its own weight in water! Depending on the brand, coco-based media may or may not contain pre-fertilised. For more information, read our blog on soil-based media

What are Soil and Soil-Based Media?

Soil is a mixture of mineral and organic matter that contains air, water, and micro-organisms, all of which play a supporting role in plant development. Soil can also contain sand, clay, and silt.

Soil contains a variety of complex organic compounds which plants rely on. But the main four are nitrogen (N), phosphorous (P), calcium (Ca), and sulphur (S). You will often find that the nutrient solutions you buy for your plants contain various quantities of these organic compounds.

The micro-organisms living in soil have a symbiotic relationship with the plant’s root network (also known as the rhizosphere). A symbiotic relationship (or symbiosis) is a long-term interaction between two organisms of a different species. For example, there are various types of fungi living in the soil which have an impact on plant life. Some fungal species are beneficial to the plant’s development, while others can be harmful.

Similarly, there are both good and bad bacteria in the soil. There are four main functional types of soil bacteria:

• Decomposers: These bacteria enhance soil fertility by breaking down proteins and starches (sugars), and other complex organic molecules. These bacteria also convert organic compounds containing nitrogen, phosphorous, calcium, and sulphur into forms that can be absorbed by plants.
• Mutualists: Mutualistic bacteria form partnerships with plants to break down atmospheric nitrogen (N2) and convert into nitrogen which can be utilised by plants. Their role is to reduce the build-up of nitrogen, a byproduct of plant and animal waste decomposition, to maintain a healthy balance in the microbiome. The soil contains four types of mutualistic bacteria, and another three types of bacteria which can break down nitrogen without the need for a plant host.
• Pathogens: These bacteria not only pose a threat to plant life, but they can also be harmful to humans. Luckily, these pathogens can be kept under control as long as there is a good balance of beneficial bacteria, microorganisms, and organic compounds in the soil.
• Lithotrophs: Another functional group of bacteria which break down organic compounds such as ammonia, carbon monoxide, and hydrogen. Like the mutualistic bacteria, they contribute to maintaining the diversity of the soil’s microbiome.

Therefore, soil-based media is a substrate predominantly made up of soil, which is oftentimes bulked out with other substrates such as perlite or clay pebbles, fytocell, and even coco to form a blend with a better balance of natural properties— aeration, water retention, and drainage— than soil alone.

There are several other types of growing media that are not either coconut or soil based. This includes sand, gravel, vermiculite, perlite, and various other materials. Some of these substrates, such as perlite, are mixed into coco and soil-based media to improve their aeration and water retention properties.

 How do I Prepare my Growing Media for Planting?

So, you now know which type of growing media is the perfect one for your set-up and the needs of your plants. But it isn’t as simple as choosing a growing media, planting seeds, and waiting for the plants to grow. Experienced growers will know that plants need an entire, well-rounded nutrition regime and feeding schedule to thrive.

You’ll now need to learn the ins and outs of preparing the growing media for planting. Regardless of the growing media you have chosen, it will need additional plant nutrients to fully optimise your plants’ environment. However, the type of plant nutrients you apply will depend on the growing media you’ve chosen. Also, there are a whole host of plant nutrient products currently on the market, so how do you know which ones to go for? It is also important to know which growth phase to apply plant nutrients and for how long.

Top Tips:

• Balance water retention & drainage: The growing medium you select must provide enough drainage to prevent waterlogging and root rot. This is a risk for most plants and is easily done in indoor growing environments when plants are typically grown in pots and trays.
• Plant feeding schedules: The growing media you use will govern the frequency and duration of your plants’ feeds. This is because, between soil and coco-based growing media, one is the natural home of plants and the other is engineered to be suitable for growing plants. Soil and soil-based media have nutrients already added. Whereas coco coir is a sterile substrate and will need all your plants’ nutrients adding to it by hand. Additionally, the media’s ability to retain, and subsequently transfer, water and nutrients from the growing media to the plant differs dramatically depending on its contents. We will discuss these natural differences in the aeration, water retention, and nutrient transfer of coco and soil-based growing media in greater detail in our second and third For more information on feeding schedules for each type of media, view our feed charts.
• EC and pH Levels: The EC and pH levels of your chosen growing medium is important for nutrient uptake by the plants. If you choose a growing medium which is naturally high in salts or tends to retain salts which cannot be absorbed by your plants, you may be at risk of damaging the root network or even killing your plants. Similarly, if you are growing plants which are sensitive to over-watering, you may want to avoid a growing media with low drainage and high-water retention.

Now that you have an idea of how to identify which growing media is right for your plants, our following two articles will offer further advice on the different properties of coco and soil-based growing media and how best to prepare each one. To learn more about coco-based growing media,check out this article. For more information on soil-based growing media, check out this article.
Interested in learning more about how Plant Magic’s range of growing media products can support the growth of your plants? Check out the full Plant Magic product range.