How to Buy Vermiculite


Vermiculite, a naturally occurring mineral, is mined in many parts of the world, including South Africa, China, Brazil, and the United States. It is often mixed with peat moss to make soil-less planting mediums used for hydroponic growing, potted plants, and square-foot gardens. Gardeners appreciate vermiculite's aerating and water-retaining properties. Additionally, vermiculite has an almost neutral pH and is disease-free. In 1990, the Libby mine, one of the major vermiculite suppliers in the United States, was closed due to asbestos contamination. Since then, many retailers stopped carrying the product or only offer it in small bags.

Step 1

Determine how much vermiculite you need. You'll probably need one quart of vermiculite if you're making a potting mix for a few potted plants. For square-foot gardening or hydroponic gardening, you'll need more, depending on the size of your garden.

Step 2

Determine the grade needed. Vermiculite is sold in fine, medium, and large grades. The grade refers to the size of the vermiculite particles. Larger particles provide good aeration and are better for outdoor applications like gardens. Smaller particles hold water, but may become compacted. Fine grades are most often used as a seeding medium in seed trays.

Step 3

Buy vermiculite in quantities of four quarts, a half bushel, or 1 1/2 bushel bags. Or order vermiculite in bulk from distributors. You can find vermiculite at local nurseries, big box stores, or online.

Tips and Warnings

  • An EPA study found that out of 16 vermiculite samples, five had asbestos contamination. The EPA says the amount of asbestos is minimal and the product is safe for gardening use. The EPA offers the following guidelines for safe use: Use a potting mix that contains vermiculite, rather than vermiculite alone. Moisten vermiculite before using it to lessen the amount of dust in the air, decreasing your chance of breathing in asbestos. Work with vermiculite outside or in a well-ventilated area. Avoid bringing it into the house on your shoes and clothing. Consider other gardening materials like peat, sawdust, perlite, or bark.


  • The Schundler Company: Horticultural Uses of Perlite and Vermiculite
  • Schundler Company: Product Guide
  • Vermiculite: Home Page
  • Environmental Protection Agency: Sampling and Analysis of Consumer Garden Products
  • Better Homes and Gardens: Make Your Own Potting Mixes

Who Can Help

  • Home Harvest: Horticultural Perlite and Vermiculite
Keywords: buy vermiculite, gardening with vermiculite, using vermiculite

About this Author

Julie Christensen has been writing professionally since 2001. She is a full-time freelance writer and former teacher with writing credits from several regional and national publications, such as Colorado Parent and LDS Living. She specializes in parenting, education and gardening topics. Christensen studied early childhood education at Ricks College, and spent 20 years as a teacher and director in university and public school settings.