Perlite vs Vermiculite

Perlite and vermiculite are two minerals that expand greatly when heated. They are commonly combined with bark or peat moss in potting mixes.

They’re often used as the growth medium in hydroponics systems. They’re also used in combination together.

They are both clean, sterile, odorless and non-toxic. Neither will rot or turn moldy. When mixed with a fertile soil the roots of young plants will get a great head start. 

Perlite - WikipediaNature of Perlite

The snow white granular particles of perlite are a form of volcanic glass. Each particle contains about 6% water. When they get heated quickly to 1800°F they become porous.

Perlite has a neutral pH, contains no seeds, insects or diseases. Tiny cavities on the surface of the perlite hold plant nutrients and moisture (3-4 times is weight), the space between them creates drainage and aeration.

Advantages: Better at draining, helps plant roots breathe, better for hydroponics, lightweight substitute for sand.

Disadvantages: lightweight and can float to the top of the soil, may create breathing problems for those susceptible, more expensive than vermiculite.

Vermiculite - WikipediaNature of Vermiculite

Vermiculite is a silicate material. Like perlite, it’s also able to hold moisture and plant nutrients. It also has a neutral pH.

It’s mined in the USA, Brazil and South Africa among other places. The vermiculite is a slightly different colour from each different place that it’s mined.

It can hold potassium, magnesium, calcium and ammonium that feed and support young growing plants. It mixes well with soil.

Advantages: retains more water than perlite, contains trace minerals, less expensive.
Disadvantages: not as durable as perlite.

In Summary:

Perlite

  • white granular particles
  • a form of volcanic glass
  • containing about 6% water
  • neutral pH
  • surface of the particles are covered with indents that hold nutrients and water
  • clean, odourless, sterile and non-toxic
  • will not rot or mold
  • better for drainage than vermiculite
  • lightweight substitute for sand
  • can float to the top of potted plants due to its light weight
  • holds 3-4 times it’s weight in water

Vermiculite

  • silicate mineral resembling mica, the colour can vary
  • retain moisture, air and plant nutrients
  • mixes well with soil
  • clean, sterile, odourless, non-toxic
  • cheaper than perlite
  • contains trace minerals
  • not as durable as perlite
  • can trap too much water causing soggy, mucky soil

2 thoughts on “Perlite vs Vermiculite”
  1. Vermiculite cheaper than Perlite? What country is that in? Not the USA! Mix for best of both worlds? They have two different purposes. Vermiculite will cause root rot in plants that like the soil to dry before watered again (Nightshades and Squash while fruit develops and Cucumbers until flowering and fruit set). Perlite doesn’t retain water for plants like lettuce and broccoli that like constant water (the soil temperature will rise faster also, causing them to bolt earlier in the season). Vermiculite adds potassium and magnesium to soil while Perlite contributes nothing. It depends what you are growing in order to decide ONE OR THE OTHER!

    1. I’m sure the price points are different depending on where you live. Your point is good. I agree, the purposes are different and the two products do different things, and more detail should be there related to individual plants.

      Regarding your second comment: I did not delete your post, it gets held in moderation until I approve it. But given your unnecessary hostility in it, I will not be approving anymore of your messages. Thank you for your input.

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