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