Grow mediums – Perlite

what is perlite?

Perlite is a popular substance which can be used on its own for hydroponic grows or added to soil or coco coir for a high quality growing medium. It has excellent air retention, prevents nutrient build up, as well as drainage capabilities, and is exceptionally light in weight, appearing like small white rocks.

It is made from volcanic glass material that has been refined by a high heating process (850 to 900 degrees Celsius). This process allows water to evaporate and the molecules to expand, which makes the end result light and airy rocks. 

perlite
(CC BY-SA 3.0)

advantages of perlite

  • Excellent water retention
  • Great air ventilation
  • Can help drainage by lightening up a heavy soil
  • Great for developing root growth, particularly with hydroponics
  • Increases oxygen in growing medium

disadvantages of perlite

  • An alkaline pH level of 7.0 to 7.5 could result in fluoride burn, so you will need higher levels of maintenance of pH levels
  • You may need to water more frequently
  • The mix will have to be washed first to get rid of the fine dust, which could jam up systems
  • You will need to keep and eye on the plant regularly to ensure your plant is growing correctly 
perlite grains
(CC BY-SA 2.0)

how to use perlite

How to use perlite

You can buy perlite in fine, medium, or coarse. For growing cannabis, fine is the type you will want. Many bought soils will come with perlite already added, if not, then you can add your own to create a high quality growing medium.

If adding perlite to soil or coco coir, you can add around 10-20% of perlite if not using too many nutrients. If you want to use a lot of nutrients, then try adding around 30-50% perlite to the mix. You can also try mixing it with vermiculite for improved water retention.

Having a mix of perlite and soil or perlite and coco coir can be a great way to encourage plant growth and increase the overall quality of your marijuana plant. 

perlite and hydroponics

Perlite goes hand in hand with hydroponic gardening, especially if the system is set up so the plant roots are constantly submerged in the water, as perlite does not hold water. With perlite being so lightweight, the roots have room to spread out, taking in more oxygen. This makes is a great medium of using cloned plants. 

perlite mix
(CC BY-SA 2.5)