1 00:00:01,920 --> 00:00:06,880 Speaker 1: Welcome to Brainstuff, production of I Heart Radio. Hey brain Stuff, 2 00:00:06,960 --> 00:00:10,719 Speaker 1: Lauren Bogle Bomb here. Tear open a bag of commercial 3 00:00:10,760 --> 00:00:14,040 Speaker 1: podding soil, and you immediately see a mixture of rich 4 00:00:14,120 --> 00:00:18,080 Speaker 1: black soil and white flex. That white stuff isn't there 5 00:00:18,079 --> 00:00:22,120 Speaker 1: by accident. It's probably pearlite, and it's an essential addition 6 00:00:22,200 --> 00:00:25,720 Speaker 1: that makes the soil more suitable for plant growth. Pearlite 7 00:00:25,720 --> 00:00:29,240 Speaker 1: promotes soil drainage so plant roots don't become water logged. 8 00:00:30,400 --> 00:00:33,199 Speaker 1: We spoke by email with John Tronfeld, director of the 9 00:00:33,280 --> 00:00:37,159 Speaker 1: University of Maryland Extension Home and Garden Information Center. He 10 00:00:37,240 --> 00:00:41,040 Speaker 1: explained it increases poor space in growing media, which is 11 00:00:41,080 --> 00:00:44,320 Speaker 1: critical for aeration, perforating the soil with pockets of air, 12 00:00:44,840 --> 00:00:48,400 Speaker 1: water drainage, and root growth. It doesn't change the peach 13 00:00:48,479 --> 00:00:52,440 Speaker 1: of growing media. Plus, it's sterile and lightweight, making it 14 00:00:52,479 --> 00:00:56,840 Speaker 1: easier to handle and cheaper to ship. But just in 15 00:00:56,920 --> 00:00:59,960 Speaker 1: case you, like me, had no idea what perlite is, 16 00:01:00,240 --> 00:01:03,040 Speaker 1: or where it comes from, or why it's called popcorn 17 00:01:03,080 --> 00:01:07,440 Speaker 1: for your soil, come along. Pearlite is a form of 18 00:01:07,520 --> 00:01:11,360 Speaker 1: amorphous volcanic glass that contains roughly two to five percent water. 19 00:01:11,760 --> 00:01:15,280 Speaker 1: It's a lot like pumice, but denser. Both types of 20 00:01:15,280 --> 00:01:19,640 Speaker 1: glass are formed as molten lava slowly cools. Composition varies 21 00:01:19,680 --> 00:01:22,119 Speaker 1: a bit, but pearlite is made of up to seventy 22 00:01:23,120 --> 00:01:27,360 Speaker 1: silicon dioxide and ten to fift aluminum oxide, plus smaller 23 00:01:27,360 --> 00:01:32,240 Speaker 1: amounts of sodium oxide, potassium oxide, and other minerals. Miners 24 00:01:32,319 --> 00:01:35,839 Speaker 1: extract perlite from the earth using explosives and or machinery. 25 00:01:36,319 --> 00:01:40,840 Speaker 1: There are large mines in countries like Armenia, China, Greece, Japan, Turkey, 26 00:01:40,959 --> 00:01:43,840 Speaker 1: and the United States. Although we here in the US 27 00:01:43,920 --> 00:01:47,039 Speaker 1: still import about a third of our processed parlite, we 28 00:01:47,120 --> 00:01:51,240 Speaker 1: get the rest from domestic mines in Arizona, California, Idaho, Nevada, 29 00:01:51,360 --> 00:01:56,000 Speaker 1: New Mexico, and Oregon. Once pearlite is taken from the ground, 30 00:01:56,200 --> 00:01:59,280 Speaker 1: processing plants crush the material into smaller pieces that are 31 00:01:59,360 --> 00:02:03,280 Speaker 1: more suitable for a variety of purposes. Then the popcorn 32 00:02:03,360 --> 00:02:07,480 Speaker 1: part comes in. Workers heat the pearlite to roughly one thousand, 33 00:02:07,520 --> 00:02:11,559 Speaker 1: six hundred degrees fahrenheit that's eight and seventy degrees celsius, 34 00:02:11,600 --> 00:02:15,880 Speaker 1: causing the water within to expand rapidly into vapor. This 35 00:02:16,000 --> 00:02:20,000 Speaker 1: creates a popcorn type reaction. The same principle that causes 36 00:02:20,040 --> 00:02:23,040 Speaker 1: the kernels of popcorn in your microwave to expand into 37 00:02:23,040 --> 00:02:27,639 Speaker 1: a delicious treat results in expanded parlite, a material that's 38 00:02:27,680 --> 00:02:31,080 Speaker 1: twenty times its original volume while being forty times less 39 00:02:31,120 --> 00:02:34,680 Speaker 1: dense and before it's popped, pearlite is usually gray, but 40 00:02:34,840 --> 00:02:38,400 Speaker 1: can be brown, green, blue, or red. Once it's expanded, 41 00:02:38,440 --> 00:02:43,680 Speaker 1: Pearlite is generally light gray to white. Structurally, expanded pearlite 42 00:02:43,760 --> 00:02:46,680 Speaker 1: is a light and airy with tiny bubbles and holes throughout. 43 00:02:47,320 --> 00:02:50,000 Speaker 1: It's low density and low price make it handy for 44 00:02:50,040 --> 00:02:54,680 Speaker 1: a variety of applications, like in lightweight plasters, insulation, ceiling tiles, 45 00:02:54,760 --> 00:02:58,800 Speaker 1: and concrete. It's perfect for noise insulation too, and the 46 00:02:58,840 --> 00:03:01,120 Speaker 1: fact that it's non flammable makes it safe for use 47 00:03:01,160 --> 00:03:04,760 Speaker 1: in many types of construction. Parlite is also widely used 48 00:03:04,760 --> 00:03:08,360 Speaker 1: in the beverage industry as a filtration agent, particularly for beer. 49 00:03:09,080 --> 00:03:12,320 Speaker 1: In its puffed form. It assists filtration by fighting clogs 50 00:03:12,320 --> 00:03:16,520 Speaker 1: that would otherwise shorten a filter's life. But for many 51 00:03:16,520 --> 00:03:20,440 Speaker 1: of us, especially anyone who's started a quarantine garden, pearlite's 52 00:03:20,480 --> 00:03:23,240 Speaker 1: unique properties are most apparent when it comes to gardening. 53 00:03:23,919 --> 00:03:26,480 Speaker 1: About ten percent of the world's pearlite use goes towards 54 00:03:26,520 --> 00:03:31,360 Speaker 1: horticulture every year. We also spoke by email with Melinda Meyers, 55 00:03:31,480 --> 00:03:36,800 Speaker 1: a horticulturist and gardening expert. She said Parlite is sterile, lightweight, 56 00:03:36,960 --> 00:03:40,200 Speaker 1: and contains lots of tiny air spaces, increasing air and 57 00:03:40,320 --> 00:03:43,840 Speaker 1: soil and improving drainage. When making my own podding mix, 58 00:03:43,880 --> 00:03:46,480 Speaker 1: I use one part Parlite, one part compost, and one 59 00:03:46,520 --> 00:03:49,560 Speaker 1: part petmas. You may need to try a few mixtures 60 00:03:49,600 --> 00:03:52,240 Speaker 1: to see what best fits your gardening and watering styles. 61 00:03:52,920 --> 00:03:55,560 Speaker 1: Like any recipe, the proportions may be adjusted for the 62 00:03:55,600 --> 00:03:58,000 Speaker 1: way the gardener likes to water and care for plants 63 00:03:58,120 --> 00:04:02,760 Speaker 1: and the type of plants they're growing. Tronfeld recommends making 64 00:04:02,760 --> 00:04:06,200 Speaker 1: Perlite ten to thirty of your potting mix, depending on 65 00:04:06,240 --> 00:04:09,640 Speaker 1: the intended use and other ingredients you have. He said, 66 00:04:10,000 --> 00:04:13,480 Speaker 1: for example, higher percentages are helpful in seed starting mixes 67 00:04:13,600 --> 00:04:17,480 Speaker 1: and for growing plants with root rot issues. Root rot 68 00:04:17,560 --> 00:04:21,279 Speaker 1: is directly related to water drainage. Aeration is another critical 69 00:04:21,320 --> 00:04:25,320 Speaker 1: factor in growing all kinds of plants because roughly of 70 00:04:25,320 --> 00:04:28,360 Speaker 1: the oxygen that plants absorbed from their environment happens through 71 00:04:28,440 --> 00:04:33,120 Speaker 1: their root systems. That's why some savvy homeowners also scatter 72 00:04:33,160 --> 00:04:36,680 Speaker 1: pearlite over their lawns. Pearlite naturally works its way through 73 00:04:36,720 --> 00:04:40,719 Speaker 1: the soil, preventing root rot and increasing aeration, resulting in healthier, 74 00:04:40,839 --> 00:04:45,520 Speaker 1: more resilient grass growth. But pearlite isn't the only way 75 00:04:45,560 --> 00:04:48,880 Speaker 1: you can improve your soil quality. Pummice, rice hulls, and 76 00:04:48,960 --> 00:04:52,720 Speaker 1: vermiculite have similar qualities, but they have characteristics that vary 77 00:04:52,800 --> 00:04:56,240 Speaker 1: depending on the issues you're wrestling with. Perlite, for example, 78 00:04:56,480 --> 00:04:59,080 Speaker 1: is best for situations when you want very good aeration 79 00:04:59,080 --> 00:05:03,520 Speaker 1: and drainage as well as good water retention, and depending 80 00:05:03,560 --> 00:05:05,719 Speaker 1: on your needs, you can blend pearlite with a variety 81 00:05:05,760 --> 00:05:08,279 Speaker 1: of substrates to create soils that are perfect for different 82 00:05:08,279 --> 00:05:12,440 Speaker 1: plant species. Myers says that peatmas, pine bark, and coconut 83 00:05:12,440 --> 00:05:16,400 Speaker 1: fiber are all commonly paired with pearlite, and just moistened 84 00:05:16,400 --> 00:05:19,000 Speaker 1: pearlite before adding it to any soil mix, and wear 85 00:05:19,040 --> 00:05:21,080 Speaker 1: a mask when you work with it. Both of these 86 00:05:21,080 --> 00:05:23,520 Speaker 1: steps will help prevent you from inhaling small particles of 87 00:05:23,520 --> 00:05:25,680 Speaker 1: pearlite that could put you at higher risk for certain 88 00:05:25,720 --> 00:05:33,559 Speaker 1: lung diseases in the long run. Today's episode was written 89 00:05:33,560 --> 00:05:36,240 Speaker 1: by Nathan Chandler and produced by Tyler Clay. For more 90 00:05:36,240 --> 00:05:38,400 Speaker 1: on this and lots of other growing topics, visit how 91 00:05:38,400 --> 00:05:41,520 Speaker 1: stuff works dot com. Brain Stuff is production of iHeart Radio. 92 00:05:41,839 --> 00:05:44,440 Speaker 1: For more podcasts my heart Radio, visit the iHeart Radio app, 93 00:05:44,520 --> 00:05:47,320 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.