Soil Is More Than Dirt

The leaves of this newly planted black-eyed susan are chlorotic

I've been busy planting more wildflowers in my developing landscape. Many of my newly planted wildflowers show signs of being confined to a pot in standard potting soil. Although they are growing and developing root systems, they are not doing as well in the pots as they do in the ground. It always amazes me how quickly new plants develop once they are planted. The reason lies in the soil, not the "dirt." 
Healthy soil is one of the most vital links to healthy plants and the reason lies in the fact that soil is much more than the dirt we pot them in. Potting soil is, by design, relatively sterile. It is a mixture of organics and inert ingredients such as perlite and wood chips - used to improve drainage. A good potting soil also comes with some time-release fertilizer. This gets seedlings off to a decent start once they are planted, but this good start often follows with relatively slow growth from that point on.  What potting soil lacks is all the things that plant roots get from healthy soil - the living components.
I devote an entire chapter to this in my new book - The Nature of Plants: An Introduction to How Plants Work. Plant roots are very inefficient at accessing water and the nutrients dissolved in it without their relationship with glomeromycetes fungi. No matter how much you fertilize a plant, it will never perform to its potential without this relationship and potting soil does not come packaged with these fungi. They occur in healthy soil. Once a root extends into the soil, it actively searches these fungi out and forms a lifetime relationship with them. Glomeromycetes greatly improve a root's ability to pull water with all of its dissolved nutrients into the main body of the plant. These fungi also protect plants from the harmful fungi, bacteria, and nematodes that might be present. It is a necessary relationship for the long-term health of a plant. Over the years, I have watched newly planted plants of all kinds burst into new vigor within days to weeks after they are planted. These black-eyed susans, pictured above, are just one of many species that are now going from slightly chlorotic specimens to deep-green individuals.
Dirt of all kinds has nutrients; it's only in healthy soil that the living components also reside. Besides the glomeromycetes fungi, healthy soil has beneficial bacteria and nematodes. It is false that all bacteria and nematodes are enemies. The vast majority are absolutely vital to the well being of your plants.
Healthy soil does not exist by accident. It occurs only where we have nurtured it. Regular pesticide and fungicide treatments, performed by lawn services, kill much more than lawn pests. It reduces the overall living component of a soil and ultimately deprives it of what your plants need most. I am fortunate that the soil I am working in has been neglected by the lawn service companies. Perhaps it's because I have a rental home and the former tenants never felt the need to "take care" of this lawn. As I rip the turf out from within the frame I established for my wildflower area and from the area I have identified for my small deciduous woodland, I find soil that appears to be "native."  Plants I've added everywhere in my former lawn have responded rather quickly; the woody plants with their more complex root systems are slower than my wildflowers, but they are now putting on excellent growth.
We feed the living components of our soil with mulches that decay - not with wood chips or, heaven forbid, inert things like gravel and lava rock which is so common in the homes around me. Decaying organic matter doesn't "enrich" a soil with nutrients that plants use directly as much as it feeds the soil's living organisms that, in turn, share those nutrients with your plant's root systems.
Don't think of your soil as "dirt." It is much more than that and never expect your plants to perform in potting soil the same way that they will perform in healthy soil. Soil is much more than the "dirt" component, it must include all of the living organisms that should be nurtured by your wise management.

Rice button aster (Symphyotrichum dumosum) is rapidly putting on good growth now that it is planted