To many beginner gardeners, dirt is dirt is dirt. It can't matter what kind you use, right? Wrong. Soil is what houses and nourishes your plants. Just as you wouldn't move into any old apartment, you shouldn't plop your houseplants into any old soil. While most plants will make do with what they're given, they won't truly thrive unless provided with the proper environment.
"A quality potting mix is important for any plant," says Summer Rayne Oakes, founder of Homestead Brooklyn and author of the upcoming book How to Make a Plant Love You. "You want to start off on the right foot." Here, everything you need to know about potting soil for indoor plants.
What is potting soil?
Commercially available potting soil is generally composed of three ingredients: peat moss (the dense dirt base), pine bark (which creates space and allows for airflow), and perlite or vermiculite (fluffy, volcanic materials that lighten the soil). It's possible to make your own custom blends—which Oakes does on occasion for the more than 600 plants that occupy her Brooklyn home. "Depending on the plant and what's available, I'll add a little extra perlite or pumice for a lighter soil," she says. However, commercially available blends will suit the needs of the vast majority of plants.
Where can you buy potting soil?
Any nursery should have a quality assortment of potting soils, says Oakes, who buys most of hers pre-mixed at a local garden center. "There are a lot of good mixes on the market," she says. "Sometimes I'll mix in extra perlite, but you should be able to buy something off the shelf." One thing to keep in mind: the brand your mother swears by in California will likely be different if you buy it in New York. Potting soils are mixed regionally, says Oakes, so formulas tend to vary. If you relocate, expect your go-to brand to have a slightly different consistency.
What kind of potting soil do you need for succulents?
While all-purpose potting soil suits most houseplants just fine, some—such as succulents—have more delicate roots that don't tolerate excess moisture. These plants require lightweight, well-aerated blends that drain quickly and prevent soil compaction. "Succulents are resilient, but you do have to be careful about moisture," says Marianne Hugo, director at Coastkeeper Garden, a nonprofit conservation garden in Orange County, California. Hugo hosts succulent classes, where she provides students with an easy, DIY succulent mix recipe: 2/3 all-purpose potting mix plus 1/3 perlite. Commercial succulent mixes vary, but generally contain a lightweight mix of peat moss, perlite and mycorrhizae, a fungus that promotes root health.
What is organic potting soil?
You're probably familiar with the term "organic" in the supermarket. But when it comes to soil, the label has a different meaning. Conventional, non-organic potting soils are sterilized to kill pests, eggs, bacteria and other microorganisms that have taken up residence. Hence, they are free of "organic" matter. Key nutrients and minerals are then added in after the sterilization process. Organic potting soils contain compost, manure, bone and blood meal, worm casings and other organic materials, which naturally supply the nutrients and minerals. Organic soils are free of pesticides and genetically engineered chemicals. Although considerably more expensive, organic soils are more nutrient-dense and environmentally conscious than conventional blends. If you have room in your budget, they’re worth the splurge. "Ideally, you want to keep everything as organic as possible," says Hugo.