What (Really) is Soil?

I’ve been aware of the differences between soil and potting mix for at least the last ten years. But I didn’t start hearing the YouTube plant people getting worked up about the nomenclature issue until about the last year or two. I figured it was a good topic to discuss with my planty friends here. (I considered using a flashy catchphrase here referencing “dirty talking”, but I won’t do that to you. Because I like you.)

Let’s talk about soil. One of the crowing glories of our Earth is its soil. It’s what allows us to live. Of course there are other major factors like the sun and our climate, but we won’t discuss those at the moment. Let’s use this simple definition of soil, “The upper layer of the Earth; made up of solids, gases, liquids and organisms; that is capable of supporting life.” Soil scientists (haha yes, that’s a real job…they’re called pedologists) actually consider soil to be a living organism. No two soil samples are alike and yes, soil can die or be killed. It’s simple really. Just take a shovelful of soil out of the ground and fling it onto a paved surface. Within a few days there will be little or no life left in that shovelful. Or even more simply you can spray harmful chemicals on a patch of soil and see the heartbreaking results.

So if this “soil” is so amazing, why does everyone tell me not to use soil to pot up my houseplants? After all, most of my favorite houseplants are native to rainforests where they grow in the soil.

That’s an excellent question. The answer is that soil from the outside does not provide the best possible growing situation for my plants in an inside microclimate. You see, if I bring some soil inside and pot up a plant with it, it won’t be long before I see bugs crawling around in my soil and probably on my plant as well. So my next course of action will be to declare all out war on the insects. Because I paid way too much money for my plant to allow these bugs to use it as a chew toy. Right? But when I rain down the Neem and soak the soil with Hydrogen Peroxide solution, it works. It kills off all the bugs (good and bad) as well as all of the microbes (good and bad) in the soil. If I’ve killed off most or all of the organisms in my soil, it isn’t really soil anymore. Now it’s just dirt.

So, I’ve killed off the insects in my potting soil which will cause the structure of the soil to break down quickly. Each time I water my plant, the soil particles will pack in tighter and tighter, until the roots of my plant are completely compacted in the not-so-living soil. Once the roots are stuck in the compacted soil, they will stop being able take up nutrients and water and will die off. Long story short (too late) actual soil is not at all a good choice for potting up our beloved houseplants.

My next post will be a blog discussing the differences between potting soil and potting mix. Please comment below if this was helpful to you and also if you have any other questions. Let’s build up this houseplant community!

Mercy, peace and love be multiplied to you.