Agriculture - Start with soil for gardening success

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With spring just around the corner, I thought it was time to brush up on some garden nomenclature. I have long been convinced in the value of understanding more about plants than the mere fact that they need sun, soil and water. The more we learn about what it is that plants need and how to determine if they are getting it, the more we will enjoy the act of gardening. What exactly do I mean about “understanding more”? Things like tilth, loam and pH can make or break your azalea garden, and adding sulfur or lime can change the growing environment, for better or worse.

So, how do we make sense of it all? Here are some important terms that many gardeners come across in their vegetable, perennial and ornamental garden endeavors. Some you may know, or not, while others may just further clarify a meaning. Understanding them will allow you to be a more responsible gardener ... with plants that live longer, bloom better, or produce a higher yield.

Soil is pretty straight forward, but what makes up the mixture determines quite a bit. Soil is comprised of sand, silt and clay. These differences are basically due to soil particle size: sand being large and gritty and silt being like talc. Typically, we are all faced with soil that is, in varying degrees, clayey. Adding sand and compost will improve the quality of heavily clay soil. The compost will add nutrients, and the sand will allow for better drainage and aeration.

“Loam” is the term used to describe soil that has good proportions of sand, silt and clay and is rich in organic matter. Loamy soil is ideal, because the intermediate texture allows for good drainage and aeration. We all want loamy soil.

Tilth is the condition of the top layer of the soil. Having good tilth means that your soil is quite workable and crumbly. Bad tilth or no tilth is caused by compaction of the soil. By definition, it is the physical condition of the soil and its ability to support plant life. Plants’ roots need water and oxygen; therefore, crumbly loose soil is the good tilth, because it allows for good drainage and aeration.

This spring when you are ready to “work” the soil in your vegetable garden, be sure the tilth is dry and crumbly before you do any digging. Working soil that is too wet, especially around here, will compact the tiny clay particles enough to make aeration and drainage even worse than it already is.

Average garden soil typically has a pH of about 7, meaning that it is neutral. Soil that is acid has a pH range of 4 to 6.5; alkaline soil has a pH over 7. Most plants do well in neutral to slightly acid conditions with a pH of 6.5.

All this becomes important, because different plants enjoy different conditions. You’ve heard the term “acid-loving” plant applied to azaleas, rhododendrons, blueberries and hollies, for example. All of these grow best, stay greener, fruit and generally flourish in soil that has a pH 6.5 (and is well-drained). Other plants, like cabbage, prefer a slightly alkaline environment, with a pH above 7.

So how do you know what your soil needs? A soil test kit can be picked up at your County Extension Service. You will be provided with the materials and instructions on how to prepare your sample properly; then return it to the Extension Service, and they will have it analyzed for you.

Once the condition of your soil is determined, you can add garden sulfur or sphagnum peat to reduce the alkalinity (to make it more acidic) or lime to make the soil more alkaline. Additionally, we are beginning to understand how important the mineralization of our soil is to maximize the availability of micronutrients to plants and livestock; a soil test is a valuable tool in determining your baseline.