An Indoor Plant Soils and Amendments Primer

An Indoor Plant Soils and Amendments Primer

Posted by Alec Thies & Jessie Jacobson on Feb 12th 2021

Choosing the right potting soil for your plants is super simple. Knowing all about the ingredients and what they do is a bit more complicated. A really great potting soil sets you up for plant parent success. This is your guide to potting soils and amendments.

Potting Soils

Espoma Organic Potting Mix
General go-to for most indoor plants. Contains 35-45% sphagnum peat moss, materials derived from one or more of the following (aged forest products, humus and/or composted rice hulls), perlite, limestone to adjust pH, earthworm castings, alfalfa meal, kelp meal, feather meal, yucca extract and Myco-Tone. All the good nutrients that most indoor plants desire.

Mycorrhizae or Myco-Tone
TheseMycorrhizal fungi have finger-like projections called hyphae that wrap around the root hairs of plants. In essence they increase the surface area of the roots allowing them to take up water and nutrients more efficiently.

Espoma Cactus Mix
This mix is recommended for cactus, succulents, palms, and citrus. 40-50% peat hummus, sphagnum peat, sand, perlite, worm castings, limestone, and Myco-Tone. This mix has good drainage and is the correct pH for making semi-desert plants happy.

Espoma Orchid Mix
Not only the perfect mix for orchids and bromeliads, but all epiphytes enjoy having this mix added into their soil. 65-75% fir bark with perlite and charcoal added for extra drainage.

Espoma African Violet Mix
African violets prefer a slightly more alkaline soil which this mix provides. 50-60% peat moss with peat hummus, perlite, and limestone. This mixture also offers excellent moisture retention.

Espoma Seed Starter Mix
A sterile mix preferred by seedlings. 75-85% peat moss, perlite, hummus, worm castings, and limestone round out this gardener’s friend. Recommend spraying with water to make damp before planting seeds.

Espoma Bonsai Soil
Haydite (expanded shale), sand pebble, and aged pine bark allow perfect drainage for these plants.

Tonka Terra
Our own specialty blend mixed to our specifications. Organic compost, sphagnum peat moss, perlite, and fine composted bark. Suitable for most indoor plants. Recommend adding additional perlite, peat, or orchid mix for added drainage.

Fox Farms Coco Loco Potting Mix
The new guy in town uses coconut coir instead of peat moss, making this a more sustainable mix. 50-60% coconut coir, aged forest products, perlite, earthworm castings, bat guano, kelp, oyster shell, dolomite lime, and Mycorrhizae. This soil holds moisture 2 to 3 times longer than peat moss blends as the coir acts like little sponges releasing water when needed. It also allows for better root aeration.

Soil Amendments

Improves drainage and acts like a filter to remove impurities that can be harmful to roots.

A form of volcanic glass, heated until it expands, used for aeration in soil.

For lightening a Seed Starting Mix, covering seeds, or blending a custom potting mix. Helps loosen heavy soils and prevents compaction.

Worm Castings
Contains over 60 micronutrients and trace minerals. Acts as a buffer when pH levels are too high or low. Humus in castings extracts toxins and harmful fungi and bacteria from soil. A great top dressing to fertilize indoor plants with or an additive to your everyday soil mix.

As the days get longer and your indoor plants start to emerge from their winter slumber, it’s time to re-pot. Grab your favorite soil mix, get your hands dirty and enjoy that earthy aroma. It’s time to re-pot!