Perlite can be easily recognized as the little white particles we have all seen in various potting mixes. It’s both easy to use and relatively cheap when compared to the other growing mediums available. Making it a great choice for people who want to do hydroponics on a tight budget. Back in the day, perlite was one of the first reliable hydroponic growing mediums available on the market.

You can find it as hard white particles mixed in potting soil mixes, but it can also be used by itself in the various hydroponic systems. Perlite can be found in multiple liquid filtration systems, soap or even insulation. Most growers in order to reduce the compaction and increase drainage and aeration will usually just add the perlite to soil and soilless mixes.

Perlite is manufactured by heating the raw material until it pops like popcorn which makes it have the porous nature of horticultural profile. In order to better understand whether perlite is right for your hydroponic system, we will look a bit deeper into what the benefits of perlite are and what it does.

What are the Benefits of Perlite?

While most of the growing mediums need extra care when it comes to pH, perlite starts out neutral in pH level, removing the need of correcting the pH level by buffering or rising. All you have to do is to simply adjust the hydroponic solution and water it in and the perlite will take on the alkalinity and acidity of the liquids you saturate it with.

Even if the perlite is dry and rinsed, the naturally occurring pH of 7.0 will not be harmful to a typical indoor garden plant species. Even though the perlite is not made of a renewable resource (volcanic rock) there is plenty of supply available on our planet. Data suggests that there is enough perlite for hundreds of years.

If you are concerned about the environment, the perlite growing medium is really use to reuse and when it comes to recycling it, it’s much simpler than other growing mediums currently available.

Unlike other growing mediums like coco coir, rockwool or even clay pebbles(aff.links), perlite doesn’t hold onto nutrients the same way they do. In order to reuse any of those growing mediums it will take several days to clean them, but when it comes to perlite you can clean it in a matter of minutes and you are good to go.

When you are removing the root balls, the perlite medium will fall away easily with a shake, just make sure you remove all of the visible organic matter which is mostly roots and then rinse the perlite until the runoff is less than 150 ppm.

In order to sterilize the used perlite medium, you will have to soak it in a 10% bleach solution and wait 20 minutes, after that rinse it thoroughly. One of the best sources of water for most hydroponic systems are dehumidifiers and reverse osmosis filters. Perlite is one of the cheapest growing mediums on the horticulture market and it’s also extremely lightweight.

When should I use Perlite in the Garden?

Using perlite greatly depends on what type of hydroponic system you are using. Typical soil is one of the obvious candidates and since it’s so heavy can become quite compacted. Organics like coco mulch and peat mass can also become compact.

This is a result of watering the soil or growing medium over time each particle gets closer to the others and air pores shrunk or get eliminated. Thus preventing the water from draining through the growing medium that well and air will not easily penetrate. This will cause a decrease in plant vigor and you will be able to easily notice the issue.

In addition to that, the roots may also fail to expand or grow in the perlite medium and there’s a chance to contract various diseases due to the lack of oxygen and overabundance of moisture. If the growing medium surface remains wet for most of the time, moss can start to grow.

If the perlite medium is used in the proper ratio, it will help resolve these issues. When your grow pots are sheltered from the wind, in order to wick away moisture from the surface, you will have to place perlite on the growing medium and will also help eliminate mold and moss.

However due to its lightweight, perlite might be an issue if used in hydroponic systems like Deep Water Culture (DWC) where it might float. While if used in ebb and flow system the perlite particles will slowly travel towards the surface of the grow pots preventing even distribution within the grow pot. Thus making the use of perlite in any grow system where flooding is essential part of it inappropriate.

Additional Information for Using Perlite

Even though perlite it’s not a synthetic material, perlite can still cause issues on the local ecological environment because it’s strip mined. If you are going to buy perlite, always make sure you research the various firms that mine it and learn how they implement the maintenance of soil composition and ecology.

Due to perlite’s ability to not hold much more than one percent moisture, vermiculture is a popular choice as it doesn’t hold considerably more water. Actually vermiculture will hold about 30 to 50 percent of its volume in water and 200 to 300 percent of its weight.

When the perlite is mixed 50/50, this will do an excellent job for providing the much needed media porosity and air. If you want to mix vermiculture or perlite with peat moss, you will have to do it in ratio of between 25 and 35 percent by volume.

Perlite is an excellent choice for many hydroponic system due to its ability to improve the aeration while it aids in providing water. Perlite is a naturally occurring inorganic, chemically inert and sterile product, which makes it safe to use because it will not add any unwanted pests or biologics into your system.

Perslite is also a great insulator so it can effectively reduce high ambient air temperatures from transferring into the growing medium when it’s used as a surface.