I call it soil, you call it dirt. When it’s wet, it’s mud. Very rarely do you encounter great, unaltered soil in the landscape. It may be too sandy, too rocky, or if you live in the Willamette Valley of Oregon, it’s clay. As in bricks, which is what our soil resembles in the summer, or pottery clay, which is what it resembles in winter. Oh sure, you may find some excellent river bottom loam around here, but if you have that soil, you’re probably not reading this blog. So you’re stuck with our clay, be it red, blue, or basic mud gray. What do you do? Alternative 1: Plant only plants that are adapted to clay. This limits your palette but is eco-friendly. Alternative 2: Remove the top 18 inches of clay and replace with good soil. Definitely not eco-friendly and it’s expensive. Besides, would the 18 inches have been enough this winter/spring to allow the water to not stand? Alternative 3: Build raised beds or berms. See alternative 2. (For initial vegetable gardens this might be a good alternative.) Alternative 4: Add compost or other organic matter when you first plant but do nothing else. It may last for a year or two but then the soil “reverts” to clay. Alternative 5: “Grow” a healthy soil by adding organic matter, mulching, encouraging worm activity, using organic fertilizer and adding/encouraging beneficial mycorrhizae in the soil. By now, you may have guessed I want to discuss Alternative 5.
I have a degree in horticulture from OSU. I graduated in 1985. I took a class in soil science, which I really enjoyed. Somehow, in the 30 years since I began my study/career in horticulture, it took me 20 plus years to grasp an understanding of how to build a healthy soil. I used organic fertilizer or organic-based fertilizer from the beginning. I endorsed the use of compost or organic matter. And I knew worms were a good sign in your yard. But I didn’t begin to put it all together until 2001, when I bought my first house. I had lived in 3 houses before that but they all had well-established yards. The soil may not have been perfect but it was better than anything I encountered in my new yard. When my husband and I began planting our new yard, my dad suggested that we add compost from his nursery compost pile. Mitch and I were skeptical. For one thing, it appeared more like plain soil than the compost I had encountered in bags. Also, we found debris in the mix, like plant tags, plastic flagging and other odd items. (This is a testament to how long plastic survives in the environment). I wasn’t sure that the pile had reached the temperature for weed seed kill, either. So Mitch and I figured we were just being polite by applying a 1-2 inch layer of this stuff all over our planting beds. The amazing thing was that almost everything in our yard grew. It grew and grew and grew. Everything grew bigger than it was supposed to grow. Even the weeds grew well. A few plants did die, but I did pick a few things that were hydrophobic.
Somewhere in this time frame I learned about mycorrhizae. The soil is alive with this incredibly large weaving of microbial threads. These fungal bodies form a mutually beneficial relationship with the roots of a host plant. They help the plant to absorb water and minerals. In turn the plant gives them access to the food they need. In the end, it makes for a healthier plant and a healthier soil. You can add mycorrhizae to your soil by using an organic fertilizer with added mycorrhizae, Espoma and Dr. Earth are two such brands. Organic gardening principles in general will encourage the growth of mycorrhizae.
Worms, wonderful worms! Worms are great. There are some questions that I hate answering at the nursery and one of the worst is “how to I discourage (get rid of) the worms that are destroying my lawn?” Worms are so beneficial that we should never want to kill them. I certainly understand that an extremely uneven ground surface can actually be hazardous. I cannot bring myself to suggest any way of removing them. My first grasp of the significance of the worm was mystical, if you will forgive my poetic license. I have a laceleaf japanese maple in my entry planting. Some of the soil we dug up to plant it was blue clay. I figured it was doomed but hoped that the fact it was in a “drier” location shielded by 2 sides of our house would allow it to live for awhile. One fall or winter I noticed the leaves that had fallen and had not been raked up (did I mention I am a lazy gardener?), were sticking out of the ground in wads. Somehow I mentioned this to my dad. He replied that the worms had pulled the leaves partially into the ground and were breaking them down. I was astounded. The worms actually pulled down debris and converted it into…what? I didn’t know. But we began to “leave” the leaves where they fell. I also mulched. We began to notice that in these areas we were seeing a lot of worms and the soil began to become “granular”. It was amazing. Even in some of the clay soil, we would encounter worms. A few years ago, thanks to Kellogg Garden Products, I finally learned what those little suckers were doing down there. They drag down food and digest it or use it to line their burrow. This can add 40 % humus to the 9 inches they are occupying. They create permanent channels that are held intact by their lubricant. Okay, there’s a lot about other biological stuff that you probably don’t want to know about (if you do, check out Wikipedia), but suffice it to say they help drastically improve soil: physically, chemically, and biologically.
If you want to learn more about how creating great soil leads to great gardens, join us on Saturday, April 2nd at 11 am. Gretchen Taylor, representing Dr. Earth products, will be sharing with us “The dirt on dirt: how to improve your soil and garden’s health”.
In the meantime, I’m busy doing the lazy gardener’s version of vermiposting. (I was unsuccessful at composting, so I’m letting the worms do all the work.) I’m thinking of starting an actual worm farm or factory. If you learn something that contradicts something I wrote, let me know. Unlike the worms, I don’t enjoy being in the dark.
Until then, Happy and Healthy Gardening. Brenda