Healthy soil = healthy plants: every gardener eventually succumbs to this fundamental principle. Nonetheless, there are still those among us that cling to the alternatives: ritualistic applications of expensive fertilizers, sprays and synthetic cure-alls in a never-ending attempt to sustain their garden.
Soil is alive. To me these are the three most important words toward achieving a successful garden. Many of us grew up in an era when we understood soil as just a sterile, lifeless accumulation of bits of rock, minerals, mud and other unknowns. We all thought . . . the more sterile and lifeless the better. As gardeners we mistakenly believed that soil just held our plants upright. It was our applications of fertilizers and chemicals that we sprayed and spread that were the source of healthy plants.
We now know that healthy soil is teaming with millions, even billions of unseen organisms in every shovel full. Since we cannot see the vast majority of these organisms we sometimes forget how essential they are; beneficial but microscopic bacteria, fungi, algae and protozoa. Earthworms, sowbugs springtails and more are all present in healthy living soil, even beneficial forms of nematodes and mites.
Rather than discourage life under our feet, we know that these organisms are essential to a soil’s fertility, structure and health. It is the invisible life in our soil that converts organic matter into nutrients, improves soil structure and wards off pests and disease. Remove these organisms from your soil, even inadvertently, and your soil will compact, lose nutrition, lack aeration and harbor root diseases.
So, all but a few gardeners still living in the dark ages now know that soil is alive. From a plants perspective, the more alive the better. What can a gardener do to create and sustain soil that is living?
A living soil begins by not killing it! As gardening consumers we are subjected to an onslaught of marketing messages that subtly “teach” us how to behave in our gardens. Here’s what NOT to do; a few ways to kill healthy, living soil:
Do not use systemic insecticides applied around roses or any other plants. This is a very inefficient way to control pests but a very effective way to kill your soil life.
Do not over cultivate. Contrary to decades of misinformation, soil should seldom be cultivated. Cultivating soil, even just the surface, does serious damage to soil life and soil structure.
Do not over use pesticides, fungicides and weed products. This would seem obvious.
Do not over fertilize. As odd as it may sound, too much fertilizer, especially phosphorus can be detrimental to soil micro-organisms. “High Bloom” fertilizers and the very popular 15-30-15 brand promises more and bigger flowers, but at the expense of beneficial soil organisms.
Now that you’re not killing your soil anymore, how can you make it even better? Remember the words “If You Feed your Soil, your Soil will Feed your Plants”. That’s exactly what invisible soil life is doing. It is releasing nutrients to your plants. But, like any living thing, soil organisms need to be fed before they can in-turn feed your plants. If you don’t feed soil organisms, they will not thrive. If they do not thrive, neither do your plants. So start feeding them. Feed your soil.
Feed my soil? What do I feed soil? Herein lies the lesson in this week’s column. Your soil feeds on organic material; it’s that simple. Apply ample amounts of organic material, composts and amendments and your soil will come alive. Living soil has to eat or it dies, and its eats organic material. Feed it.
Feeding soil is simple. Get as much high-quality, blended organic compost or mulch as you can and spread it on top of the soil in your garden. In most areas this layer should be about two to three inches thick – really. You do not need to dig it in; in fact dig it into an existing garden may do more harm than good. Just put it on top. Keep adding more throughout the year to maintain this organic layer on top of the soil. You’ll notice that it will disappear after a short while. Where is it going? Invisible micro-organisms are eating it. As long as you keep feeding (adding organic material), they will keep eating and multiplying. Your soil will become healthy again; water will percolate in, diseases will diminish and your plants will grow better than ever.
After an explanation about the importance of mulching, the hardest part for most gardeners to accept is that they do not need to dig their soil. They can’t figure how an organic layer on the top of their soil will improve the soil beneath. It will; dramatically.
With diligent mulching, where you can now barely push a shovel halfway into the hard ground, you may not even need to use a shovel. In that same dry, hard, dead soil where plants once struggled you will be able to dig a hole with your bare hands. Plants will grow stronger and healthier and more pest and disease free.
Soil was once dead. You began feeding your soil. Now your soil is alive and your plants are thriving. Feed your Soil and your Soil will Feed your Plants.
Ron Vanderhoff is the Nursery Manager at Roger’s Gardens, Corona del Mar