Benefits of Perlite as a Grow Medium


Hydroponic gardening offers growers many options for growing in a controlled environment. You have a wide range of systems, artificial lighting, nutrients and fertilizers, and grow mediums. In fact playing around with different types of grow mediums can be much of the fun of hydroponic growing: it comes down to a learning experience.

In a previous post, we described the benefits of using coconut coir as a grow medium in hydroponic gardening. Now we’ll explore another versatile grow medium: perlite.

Perlite as a Grow Medium

Perlite is an inert, porous, and lightweight substance often used as a hydroponic substrate. Perlite as a grow medium is most recognizable as little white rocks. It’s a type of volcanic glass that, when heated to a certain temperature, expands to several times its size. As perlite is relatively inexpensive and easy to use, it’s a popular option for a grow medium among growers. It can be used on its own or in a mixture with another grow medium.

It’s worth mentioning that perlite is a non-renewable resource which will have some impact on the decision making process for some growers. However, there is a vast global supply of perlite in existence. Perlite as a grow medium is also easy to reuse therefore its longer life cycle is a great benefit when considering environmental impact.

Black Gold’s Perlite product. Image via Sunlight Supply.

Benefits of Perlite

Because perlite is a porous substance it offers both excellent water retention and drainage capabilities – both important in hydroponic gardening. Additionally, perlite also provides proper aeration which is necessary for healthy root growth in plants.

Perlite in an inert and sterile medium which means it’s safe to use without the fear of tracking in pests, which is always the risk with soil. Perlite has a neutral pH level but will take on the acidity or alkalinity of the nutrient solution it’s placed in. Perlite can be washed and dried to be restored back to its 7.0 pH level.

While perlite is the perfect substrate to re-use by washing, it’s also a medium that will not decompose so it’s guaranteed to last for years.

In terms of plant health, perlite as a grow medium strengthens root growth and also acts as a terrific insulator to protect plants from temperature changes.

Learn more about the types of perlite products and brands available for your hydroponic garden.

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