Dripping Gardening

Did you ever stop to wonder why good healthy soil smells so incredibly wonderful? For that you can thank actinomycetes (ac-ti-no-my-cetes). But don’t worry if you’ve never heard of them or even about how to pronounce their name. Just know that they are living microorganisms that help stabilize decaying organic matter and are responsible for giving soil that heavenly, yet so earthy smell.

On the other hand, if you did learn how to pronounce it, just think how impressed your friends and family would be! In Rachel Carson’s classic book, “Silent Spring,” she describes in prophetic detail how soil undisturbed by man or chemicals is teeming with life, microscopic organisms that work symbiotically and synergistically with each other and with the plants and roots to provide an efficient and highly sophisticated infrastructure. Collectively, these microorganisms allow flora and fauna above and below the ground to thrive, naturally.

In one of the most recent books for gardeners on the science of soil, Jeff Lowenfels and Wayne Lewis shed new light on, until recently, a mysterious world. Their book, “Teaming with Microbes; A Gardener’s Guide to the Soil Food Web” digs into soil in a most enlightening and entertaining way.

How strange that for so long, many gardeners and even industry professionals thought that bacteria, fungi, and protozoa in the soil were a bad thing! Although there are certainly good and bad versions of each, we now know that there are many very good living organisms in soil that has not been tainted by overuse of chemicals.

Only since the invention of the electron microscope, have soil scientists been able to fully study and understand the symbiotic relationships within the soil. Since then, we’ve learned that a single teaspoon of garden soil can contain over a billion bacteria. We discovered that plants attract bacteria and fungi to their roots so that protozoa and nematodes will eat these single-celled organisms, and then excrete the excess nitrogen in a form that feeds the plants.

The bottom line is that all plants do better in soil that is alive with beneficial soil microbes. Yet until recently, we didn’t realize just how much damage we were doing! Generation after generation, through conventional gardening practices, we have unknowingly striven to promote a soil environment that was anything but alive. The implication of these facts soon became clear. Using high-salt, dehydrating, chemical fertilizers can kill fungi and bacteria at the base of the soil food web and impacts larger members as well.

In our eco-friendly garden, our best asset is healthy soil. That means feeding the billions of beneficial microbes and other subterranean creatures the diet they need to thrive and multiply. Organic matter sums it up but specifically compost, aged manure, mushroom compost and leaf mold is a good place to start.

“Applying herbicides, pesticides, nemacides, fungicides, and all the other “icides” are practices that hurt the natural order — that complicated but elegant linking of food chains, from the single-celled organisms all the way up to man.” as Lowenfels and Lewis point out.

What all of this new science means is that we have to make an adjustment to the way we work and play in our yards, gardens and landscapes. It is incumbent upon us to take into account the real science of the soil, and to consider the consequences of negatively impacting the soil food web.

We live, not only in a new year, but in a new era, from how we communicate to how we garden. It is up to each one of us to embrace the tools that have recently been made available through science (and books) to reduce and even eliminate the environmental footprint we have created. As you move away from feeding your plants to feeding the soil, you will be encouraged to know that gardening actually becomes easier. The natural balance in a healthy, sustainable soil food web makes for healthier plants that look great and are more pest and disease-resistant, all while producing far better too.

True gardeners rarely refer to soil as simply dirt. They understand the difference between the stuff you dig up in your backyard versus the “black gold” that consist of compost, manure, decomposed organic matter and millions of beneficial microbes that are actively at work underground.

Fortunately, converting dirt to soil is an easy process. Within this context, understanding three commonly used gardening terms – texture, structure, and tilth – should help clear up one of the dirtier mysteries of gardening.

Let’s start with soil texture. Texture refers to the relative percentage of sand, silt and clay within the soil. Ideally, you want to have an equal amount of each. When these three are proportionate, the soil is said to be loamy. Soil with great texture allows plant roots to spread, moisture to be retained (but not to excess) and essential air pockets to exist between the tiny spaces of the soil particles.

Next is soil structure. Simply put, structure is how sand, silt and clay fit together. Good structure is evident when the soil holds together if squeezed in your hand but then breaks apart or crumbles easily when disturbed. As I work to achieve ideal soil structure, I am constantly working to blend the right amounts sand, silt and clay to get the results I described above. But don’t over-think it. A diverse mix of soil components will pretty much assure you’ll achieve that goal.

In my garden beds, (which natively consist of (mostly) good ol’ Texas black-clay gumbo) I usually find adding plenty of compost and aged manure will soon do the trick. The compost is home made. However, the cow manure is another story. Fortunately, composted manure is available by the bag at many garden centers and home improvement stores.

When soil has good tilth, it drains well. It is loose enough to allow for adequate drainage, yet dense enough to retain moisture long enough for plant roots to utilize it. This is why garden soil should neither contain too much sand nor too much clay.

The key is to know from which extreme you are starting. If soil is too dense, then your action is to loosen it up by adding gritty organic material like composted bark. For soils that are too loose, you want to increase the water holding capacity. Sphagnum peat moss is an option for this. However, in either case, organic material continues to break down over time. Monitor your soil constantly and amend when needed. If you are unsure how to proceed then I recommend you add compost. This is because I consider compost to be garden magic, it improves the drainage and/or water retention abilities of soil and adds necessary microorganisms that positively effect soil texture, structure, and tilth.

Understanding what makes perfect soil will get you well on your way to having the best garden ever. Regardless of your current soil texture, structure or tilth, you can change what you already have. Call it a soil makeover if you wish. But by simply adding organic material like good quality compost (I like mushroom compost), humus, composted manure, leaf mulch, peat moss, etc. – and a bit of persistence – you can greatly improve any soil.