Soil Searching: Picking the Right Soil for Indoor Plants

Have questions about which type of potting soil is right for your indoor plants? It’s understandable—you’re bound to find a wide variety of soils at your local garden center, including prepackaged mixes for house plants. The type of soil you need really depends on the type of plant you have.

First, it’s important to understand that what you get in your mix might contain little in the way of actual soil. This is because soil can become compact inside a container, which makes it difficult for the plant’s roots to take in the oxygen and nutrients they need. So while it might be called soil, it also might not actually resemble soil as you know it.

Here are some things you should consider as you choose your potting soil.

Plant needs

House plants have varying preferences for soil acidity and alkalinity. Therefore, you should come knowing your plant’s preferred soil pH value. A pH7 value is neutral on the scale of 0-14. Higher numbers are alkaline soils, and lower numbers are acidic soils.

The type of potting soil you choose should provide your plant with plenty of support to keep it falling over, and should be capable of storing water and nutrients for the plant’s roots while still providing enough drainage to keep the pot from filling with water. This drainage also provides air circulation, giving the roots enough oxygen to keep growing.

Potting soil varieties

You should also have a general understanding of what’s actually in the various options for plant mixes. Take a look at the contents and ingredients on a bag of potting mix before you purchase them. Here are some of the most common ingredients:

  • Peat moss: This is the most common and basic ingredient in most potting mixes you’ll find in stores. They use semi-decomposed bog plants which are they ground up into a coarse powder. Some types of plants like especially moist soil environments, like African violets, begonias and ferns, making peat moss-based potting soils ideal.
  • Bark: You’ll probably notice chunks of tree bark as you work with potting soils. These pieces help with draining and keep the soil from becoming overly compact.
  • Perlite: Perlite looks like white puffs of Styrofoam, but is actually expanded volcanic rock filled with air pockets to improve drainage and better regulate the release of water in the mix.
  • Sand: Sand is also used to improve drainage in potting mixes. Especially sandy mixes are perfect for plants like cacti and succulents, which prefer smaller amounts of water.
  • Vermiculite: This is a material made from a variety of mineral deposits and helps to maintain air circulation in the mix. It can absorb several times its weight in minerals and water, and releases them slowly.

For more information about what you should consider when buying potting mix, contact us today at Soil Advocates –

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By |2019-03-26T09:30:58-04:00March 26th, 2019|Categories: Blog|

About the Author:

Dr. Leanne J Philip, BSc. (Hon.); MSc.; PhD. is the Managing Director & Chief Scientist of Soil Advocates Inc. She studied at the University of Guelph as an undergraduate (Plant Biology, Environmental Management and Urban Horticulture) and as a graduate student (Plant & Soil Interactions). She has a keen interest in soil sciences, which lead her to the University of British Columbia in Vancouver for doctoral studies in soil carbon sequestration and movement within British Columbia’s clear-cut soils. Further work in soil sciences in Europe and Canada reinforced Dr. Philip’s belief that soil processes and mechanisms belowground drive aboveground aesthetics and plant interactions. While active in both research, mentorship and teaching, most recently Dr. Philip has been working in applied soil sciences in industry and community outreach. Dr. Philip is a native of southern Ontario and is a strong advocate for scientific literacy within her community and responsible environmental stewardship.

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