What Is The Difference Between Soil-Based and Soil-less Potting Mixes?

Ask The Expert: Your plant-care guidelines for the Golden Pothos Ivy plant states that the plant needs a soil-based potting mix to prosperously flourish in, but at the Lowes, Home Depot, etc. nurseries, they have no potting mixes labeled “Soil-based” or even listing its soil contents, yet the stores claim that all of their potting mixes are soil-based?? I tried using Miracle Gro potting mix, but it rotted off (just above the top of the soil); 4 pots of Golden Pothos plants of mine, it did that time and time again as I would clip and replant them in the soil-and they got watered only once a week,(indoors): Could you kindly assist me in properly identifying good “Soil-based” potting mixes? thanks in advance: Sincerely,
Robert Campbell.

Plant Expert Reply:
It is kind of funny that the industry uses the terms soil-based and soil-less when referring to the type of potting mix in plant cultural information. Yet, they don’t use these terms when marketing the products for sale.

So here is a little guide to help you select the correct soil. Soil-based potting mixtures will contain things like peat, sand, vermiculite, or perlite. They generally weight more than soil-less mixtures. I like to think of soil-based potting mixtures as being a little “beefy” since they will clump together if you apply pressure. Soil-based potting mediums contain materials that naturally retain water and nutrients. Think of your soil particles – sand, silt and clay. Soil-based potting soils will have the same properties of these soil types.

Soil-less potting mixes are contain mostly peat, barks, pulmice type materials or a peat substitute like composted coconut husks. These airy and lighter weight materials allow water and nutrients a greater opportunity to evaporate or drain from the mixture. They “fluff” the soil but do not have any soil properties. Many soil-less potting mixes are specially labeled (referencing the plants that need this type of mix – like orchid soil or cactus soil).

Although Miracle Gro is an ok potting medium, it often contains a wetting agent and maybe the cause of your problems. In your case, I recommend Baccto potting soil – it is composed of reed sedge peat, perlite, sand, limestone and a few other ingredients.

I also recommend that you treat plants with established roots differently than the plants you are trying to root. With established plants wait until the soil is dry (at a 1″ depth) before you water and make sure your container has good drainage. On the plants that you are trying to root, keep the soil moist to the touch but not soggy. At the first sign of rooting pull back on your watering.

Please keep me posted. Good Luck.

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