With the advancement of technology and innovations, man has been able to prove that it is possible to grow plants without soil. This soil-less solution is popularly known as hydroponics gardening.
Plants grown through this solutions mature early and are not prone to diseases. However, to make this technique successful, something else (grow media) must be introduced to play the vital role that soil plays while growing plants which is providing support.
That’s why grow media is necessary in any hydroponics system as it is used as the soil alternative in this modern gardening technique. Just like soil, the primary goal of grow media is to provide support to the plant’s roots, allow proper circulation of water and oxygen throughout the system.
The market today is filled with many inert grow media and many gardeners often find themselves in a dilemma when trying to choose the best grow media to use in their system.
If you are a hydroponics enthusiast, this article will expound on the various grow media available in the market thus, helping you make a better decision when shopping for the one suitable to your system. In general, there is no single grow media that is better than others but their performance depends mostly with the type of hydroponics system that you are using.
The following is a detailed list of the most common types of grow media in the market. I will give you unbiased review detailing their specific features, advantages and disadvantages of using each of them.
Vermiculite is one of the most popular grow media. Because it’s a mined mineral rock, it comes with different features for different uses and it is advisable that you select the one that works with hydroponics.
Vermiculite is very light and it can float easily. It is mostly preferred due to its high ability to retain moisture. Thus, when vermiculite is used as a grow media, it can retain nutrients for a longer duration compared to others.
However, this media is not efficient with oxygen supply and if possible, you can use it together with other grow media such as perlite where vermiculite will provide the needed support and moisture while perlite will be responsible for sufficient oxygen supply.
#2. Coco fiber/ coco chips
Coco fiber/chips grow media as the name suggests, they are made from the outer husk of coconuts. The difference between coco fiber and coco coir is the size but both do not decompose easily (inert media). Coco fiber/coir is PH neutral, hold moisture perfectly, and allows efficient aeration to take place.
Both coco fiber and coco chips are compatible thus, making them easy to transport. Once you soak them, they can expand up to 6 times of their original size.
#3. Oasis cubes
Oasis cubes are made of open cell materials and the cells help in absorbing both water and air. With oasis cubes, gardeners can used it as grow medium for both seeds and cuttings. Oasis cubes have similar characteristics as Rockwool grow media and it is mostly preferred due to its high moisture retention and Neutral PH Level.
The open cell structure provides an ample space for roots to grow and at the same time giving room for moisture and aeration.
This is another popular grow media in hydroponics. Rockwool is mostly preferred because it is porous, sterile, and non-degradable. Rockwool grow media comprise of thin threads made from heating and melting limestone or granite.
The small threads are then compressed to form blocks, cubes, slabs, flocking or sheets. Before using Rockwool, ensure that you have soaked it in PH balanced water to ensure that it’s PH Neutral.
It is also worth noting that Rockwool has high water absorption capacity and can lead to water logging. Therefore, close monitoring is necessary to avoid over saturation.
Perlite grow media is a combination of volcanic glass that is heated to pop up in a similar manner as popcorns. They are good in water drainage and aeration. Once heated, perlite becomes very light and it floats easily. Therefore, for better results, it should not be used alone and vermiculite can be added in the ratio of 1:1 to provide additional strength.
Perlite is reusable and it is available at very affordable prices. The only downside with perlite is that; it does not have better water retention ability. When using this grow media, care should be taken to ensure perlite dust does not get into your eyes as they are harmful.
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#6. Grow rock
Grow rock are made from clay soil which is heated to create porous texture particles. They are a bit heavy meaning that they don’t float thus providing support to your plants. Grow rock is also known as hydro corn and some of the best characteristics of this grow media are;
- Neutral PH
- Good moisture retention
- Re usable
Grow rock is popularly known and you can easily find it at your nearest hydroponics store.
Yes, sand can also be used as grow media. Sand particles are smaller compared to rock particles and this makes it better in terms of moisture retention. For better results, sand can be mixed with vermiculite, perlite or with coco coir to increase its ability to retain moisture and improved aeration.
Unfortunately, sand is usually heavy meaning that you cannot transport it easily compared to other compatible grow Medias. The larger the grain size of sand that you select, the better the aeration.
#8. Brick shards
Brick shards is derived from crushed bricks to form small bricks particles. Brick shards are easily available but you must thoroughly clean them before use. In addition, brick shards are not PH Neutral meaning that they can interfere with the PH level of your water solution.
They have a good drainage potential and they can easily be found at home improvement stores near you at very affordable prices.
Gravel is easily available and it has been widely used in aquariums. If you are a beginner looking for a cheap grow media, the gravel is the best choice since it is not expensive. It is easy to clean and it drains very well.
The only con of using gravel as a grow media is that; it might cause heavy plants roots to dry out. Thus, close monitoring is required.
Pumice is a mined mineral and it resembles perlite in a number of ways. Pumice is lightweight thus easy to transport, it has perfect aeration potential, and it is inexpensive.
Just like perlite, pumice is also too light and this feature makes it not suitable for certain hydroponics systems. Pumice is easily available.
#11. Rice hulls
As the name suggests, rice hulls are grow media that is made of shells that surrounds rice particles. After rice is harvested, rice hulls are thrown away as waste.
Rice hulls have good drainage and high water retention potential and it’s due to this features that makes them suitable to be re-used as grow media in hydroponics.
Rice hulls are easily available depending on your location and they can be sourced at very affordable prices. The only weakness with rice hulls is that they short life time (decay over time). Rice hulls comes in different varieties ranging from; fresh, composted and parboiled, aged or carbonized.
#12. Starter plugs
Starter plugs are commonly used for starting seeds which are eventually transferred to the hydroponics system. Starter plugs are made of organic compost of biodegradable binding material which makes them strong and do not break easily.
If you are looking for a modern way of raising many seedlings or cloning, starter plugs are the best to go for. They are easy to use as you only need to place them in trays and the roots of the new plants will grow straight downward making it easy to transplant them into your main system.
#13. Grow stone hydroponics substrate
Grow stones are similar to grow rocks but they are made of recycled glass (clay and shaped marbles). Grow stones are light weight, unevenly shaped, and porous.
They are reusable and they provide good aeration and moisture capacity.
All the above grow media are readily available in the market and you can now make an informed purchasing decision based on each grow media specific pros and cons as well as the type of hydroponics system that you are using to grow your plants.
Since there is no proven grow media that is best from the rest, always go for one that has;
- Good moisture retention potential
- Good aeration
- Ability to provide the needed plant support