Let’s Talk Dirt!

by Carolee James

When I was a small girl I made dirt mud pies with my friends and had tea parties with our dollies. Later, when I became a tomboy, I dug underground forts in the neighboring fields. I guess because of my affinity for dirt, much to my mother´s dismay, it was destined that I become a gardener who loves to dig in ´dirt´! However, the dirt I´m digging in today is much different than the dirt I played in as a child. My dirt has been amended, fertilized and mulched! And it is now called ´soil´!

As all gardeners in the Mother Lode know, our soils are not always conducive to the type of plants we want in our gardens. While native plants have adapted to clay soils, non-natives have a difficult time growing unless the clay soil has been amended with material that loosens the dense particles of clay. While I am a great proponent of planting native species, I, like all of you, enjoy adding non-natives to areas of my garden. And amending the soil is the only way I can insure that they will grow and prosper.

So it´s off to the garden center and what do we find… bag after bag of soil amendments, soil conditioners, compost, and mulches. What to buy and what to ignore? That is the question. Here´s a brief guide that I hope will aide in your selection.

First, the difference between mulch and a soil amendment. When you use a soil amendment you need to work it into the soil at least several inches. Mulches, on the other hand, are spread on top of the soil to conserve moisture and suppress weeds.

Compost: Compost is any organic matterƒ??from leaves to manure to municipal wasteƒ??that has broken down into a rich, dark, crumbly substance called humus. Compost feeds the soil, improves its texture, often contains micronutrients, and encourages important microbial activity. It is one of the best things to add to all soils because it both fertilizes and improves texture. For good bagged compost, you may pay a premium price. However, you can make your own compost with grass trimmings, leaves, kitchen waste, and manures. Why pay for something easily done in a 4´x4´ square pile in your backyard? And once you have improved your soil, you can use more of your compost as mulch. Also, finely chopped or rotted leaves can be either worked into the soil or spread on top of it for mulch. A two for one product!

Soil amendment vs. soil conditioner: They are the same! No matter what the maker calls it, either of these products will improve the texture and often the fertility of the soil. But, it´s what´s in the bag that counts! The more specific a manufacturer is about what´s inside, the more likely the bag contains something worth boasting about. Beware of the bags with little or no information as to content. Also, consider the weight of the bag which has nothing to do with quality. Bags of good amendments are usually lightweight as they do not contain sand, low-quality peat or even water. What they may contain in any combination is; sphagnum peat moss, gypsum, vermiculite, perlite, poultry manure, forest products, composted rice hulls and perhaps some lime. These products will break up the clay soil and will also add texture to sandy soils and make them more water retentive.

Sphagnum peat moss: Peat moss breaks up heavy clay soils and makes sandy soils more moisture-retentive. It is an easy and cost-effective way to add organic matter to the soil. There are some environmental concerns about harvesting peat moss from peat bogs and so there are new “peat alternative” products that claim to have the same advantages. I have not used them so I am not able to speak to their reliability. Plain ´peat´ is heavier and darker than sphagnum peat and is not a good addition to your soil.

Once you have amended your soil, you should test it for the pH level. Every gardener should have a home soil testing kit. They are fairly inexpensive and can help your plants by insuring that they are growing in the right pH level. Most garden plants do well with a pH of 6-7, however acid-loving plants like azaleas and ferns require a pH of 5-6. To achieve the desired pH for your plants add sulfur to lower the pH (make your soil more acid soil) and lime to raise the pH (make your soil more alkaline soil). Test your soil each year before adding further amounts of these elements and always follow manufacturer´s guidelines. Master Gardeners no longer do soil testing, so having a soil test kit is a must if you want to have the right pH for your plants.

Mulch: Once you´ve amended and tested your garden soil, and planted, now comes the mulch. Mulching not only conserves moisture and reduces weeds, but it also breaks down, adding texture and, if compost is used as the mulch, nutrients. It´s a win-win situation for you, the soil and your plants. Mulches to consider besides compost are: shredded bark, redwood mulch and forest bark. If you are fortunate to have a chipper/shredder, run all your tree, shrub and perennial prunings, as well as leaves and bygone annuals, through your machine and use this material as mulch. It will save on your water bill and you will be improving your soil.

Finally, once you have found a product that you like, stick with it. I can´t tell you how many times I tried a different brand only to be disappointed in the results. Knowing what I like allows me to bypass all those bags in the garden centers!

Carolee James spends several hours throughout the year using her chipper/shredder to make mulch for her garden. As she states, “There is always something that needs cutting back or pruning!”