Speaker 1: Welcome to Brainstuff, production of I Heart Radio. Hey brain Stuff,
Speaker 1: Lauren Bogle Bomb here. Tear open a bag of commercial
Speaker 1: podding soil, and you immediately see a mixture of rich
Speaker 1: black soil and white flex. That white stuff isn't there
Speaker 1: by accident. It's probably pearlite, and it's an essential addition
Speaker 1: that makes the soil more suitable for plant growth. Pearlite
Speaker 1: promotes soil drainage so plant roots don't become water logged.
Speaker 1: We spoke by email with John Tronfeld, director of the
Speaker 1: University of Maryland Extension Home and Garden Information Center. He
Speaker 1: explained it increases poor space in growing media, which is
Speaker 1: critical for aeration, perforating the soil with pockets of air,
Speaker 1: water drainage, and root growth. It doesn't change the peach
Speaker 1: of growing media. Plus, it's sterile and lightweight, making it
Speaker 1: easier to handle and cheaper to ship. But just in
Speaker 1: case you, like me, had no idea what perlite is,
Speaker 1: or where it comes from, or why it's called popcorn
Speaker 1: for your soil, come along. Pearlite is a form of
Speaker 1: amorphous volcanic glass that contains roughly two to five percent water.
Speaker 1: It's a lot like pumice, but denser. Both types of
Speaker 1: glass are formed as molten lava slowly cools. Composition varies
Speaker 1: a bit, but pearlite is made of up to seventy
Speaker 1: silicon dioxide and ten to fift aluminum oxide, plus smaller
Speaker 1: amounts of sodium oxide, potassium oxide, and other minerals. Miners
Speaker 1: extract perlite from the earth using explosives and or machinery.
Speaker 1: There are large mines in countries like Armenia, China, Greece, Japan, Turkey,
Speaker 1: and the United States. Although we here in the US
Speaker 1: still import about a third of our processed parlite, we
Speaker 1: get the rest from domestic mines in Arizona, California, Idaho, Nevada,
Speaker 1: New Mexico, and Oregon. Once pearlite is taken from the ground,
Speaker 1: processing plants crush the material into smaller pieces that are
Speaker 1: more suitable for a variety of purposes. Then the popcorn
Speaker 1: part comes in. Workers heat the pearlite to roughly one thousand,
Speaker 1: six hundred degrees fahrenheit that's eight and seventy degrees celsius,
Speaker 1: causing the water within to expand rapidly into vapor. This
Speaker 1: creates a popcorn type reaction. The same principle that causes
Speaker 1: the kernels of popcorn in your microwave to expand into
Speaker 1: a delicious treat results in expanded parlite, a material that's
Speaker 1: twenty times its original volume while being forty times less
Speaker 1: dense and before it's popped, pearlite is usually gray, but
Speaker 1: can be brown, green, blue, or red. Once it's expanded,
Speaker 1: Pearlite is generally light gray to white. Structurally, expanded pearlite
Speaker 1: is a light and airy with tiny bubbles and holes throughout.
Speaker 1: It's low density and low price make it handy for
Speaker 1: a variety of applications, like in lightweight plasters, insulation, ceiling tiles,
Speaker 1: and concrete. It's perfect for noise insulation too, and the
Speaker 1: fact that it's non flammable makes it safe for use
Speaker 1: in many types of construction. Parlite is also widely used
Speaker 1: in the beverage industry as a filtration agent, particularly for beer.
Speaker 1: In its puffed form. It assists filtration by fighting clogs
Speaker 1: that would otherwise shorten a filter's life. But for many
Speaker 1: of us, especially anyone who's started a quarantine garden, pearlite's
Speaker 1: unique properties are most apparent when it comes to gardening.
Speaker 1: About ten percent of the world's pearlite use goes towards
Speaker 1: horticulture every year. We also spoke by email with Melinda Meyers,
Speaker 1: a horticulturist and gardening expert. She said Parlite is sterile, lightweight,
Speaker 1: and contains lots of tiny air spaces, increasing air and
Speaker 1: soil and improving drainage. When making my own podding mix,
Speaker 1: I use one part Parlite, one part compost, and one
Speaker 1: part petmas. You may need to try a few mixtures
Speaker 1: to see what best fits your gardening and watering styles.
Speaker 1: Like any recipe, the proportions may be adjusted for the
Speaker 1: way the gardener likes to water and care for plants
Speaker 1: and the type of plants they're growing. Tronfeld recommends making
Speaker 1: Perlite ten to thirty of your potting mix, depending on
Speaker 1: the intended use and other ingredients you have. He said,
Speaker 1: for example, higher percentages are helpful in seed starting mixes
Speaker 1: and for growing plants with root rot issues. Root rot
Speaker 1: is directly related to water drainage. Aeration is another critical
Speaker 1: factor in growing all kinds of plants because roughly of
Speaker 1: the oxygen that plants absorbed from their environment happens through
Speaker 1: their root systems. That's why some savvy homeowners also scatter
Speaker 1: pearlite over their lawns. Pearlite naturally works its way through
Speaker 1: the soil, preventing root rot and increasing aeration, resulting in healthier,
Speaker 1: more resilient grass growth. But pearlite isn't the only way
Speaker 1: you can improve your soil quality. Pummice, rice hulls, and
Speaker 1: vermiculite have similar qualities, but they have characteristics that vary
Speaker 1: depending on the issues you're wrestling with. Perlite, for example,
Speaker 1: is best for situations when you want very good aeration
Speaker 1: and drainage as well as good water retention, and depending
Speaker 1: on your needs, you can blend pearlite with a variety
Speaker 1: of substrates to create soils that are perfect for different
Speaker 1: plant species. Myers says that peatmas, pine bark, and coconut
Speaker 1: fiber are all commonly paired with pearlite, and just moistened
Speaker 1: pearlite before adding it to any soil mix, and wear
Speaker 1: a mask when you work with it. Both of these
Speaker 1: steps will help prevent you from inhaling small particles of
Speaker 1: pearlite that could put you at higher risk for certain
Speaker 1: lung diseases in the long run. Today's episode was written
Speaker 1: by Nathan Chandler and produced by Tyler Clay. For more
Speaker 1: on this and lots of other growing topics, visit how
Speaker 1: stuff works dot com. Brain Stuff is production of iHeart Radio.
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