As a first-year college student studying horticulture (and later agronomy) I had no idea what I was in for when I signed up for that first Introduction to Soil Science course. Growing up, gardening and working on my family’s dairy farm, soil was something that we often talked about, mainly if it was wet or dry, rocky or smooth, and of course to stay out of the garden when it was wet; however, I really didn’t understand how important managing it was or how many different parts could be studied!
The technical definition of soil is the natural body composed of solids, liquids, gasses, and living matter that is capable of supporting plant life and has properties resulting from the five factors of soil formation. Wow! A mouthful of words, but a key point from this definition is the word NATURAL— soil is what covers the earth naturally and helps to absorb and disperse solar radiation and precipitation. It also provides an anchor for plant life. With harsh treatment, this living portion can be damaged and thus can take many years to build back. It is important to know too that healthy soils help to mitigate climate change as they store a huge amount of carbon in the form of carbon dioxide (CO2) and organic matter.
Soil is not what you buy inside of plastic bags from a garden center. That product is soilless growing media and does not occur naturally; the components are natural, but not found in the same ratio or all in the same area of the world. While this product has many lovely uses and works beautifully for specific purposes, it is very different from natural soils. Soilless growing media should not be used as a soil amendment in your garden; that is a waste of your money. Soilless growing media is specially formulated for use in containers, which include raised beds (because of their large size you can mix compost and a soilless growing mix in a 1:1 ratio). For guidance on soil amendments for your garden visit this University of Maryland Extension website.
Soil is not just important for gardening and supporting plant life. It is the medium that we literally build our lives on. The type of soil determines all aspects of infrastructure— roads, buildings, water drainage, waste disposal systems, the water cycle, and so much more! There are at least 775 different types of soils identified in Maryland (PDF). Every soil in the United State is mapped and can be found on the Web Soil Survey, an incredible tool for learning more about your soil type and many different uses. The online platform allows you to map out sections and measure areas. Below are examples of some information you can find on the Web Soil Survey.
There are many regional collegiate soil competitions that focus on soil judging, figuring out soil type, and so much more. Watch this great video to learn about a few techniques that these young professionals use to judge and learn more about soils. Hopefully, you can apply some of the concepts and judging techniques to your own garden! For example, look at the color of your soil. Good soil is generally darker brown in color, indicating the presence of organic matter (carbon).
So what makes soil good? Well as with most things, beauty might be in the eye of the beholder, but for gardeners, good soil is anything that can support and produce whatever crop is being grown with minimal problems. Fortunately (or unfortunately) soil gets many of its qualities from the parent material ( i.e. type of rock that it came from, for example, sandy soils come from sandstone) and most of these properties cannot be changed, such as structure and texture. However, the management practices listed below can help to improve and protect your soil. Sometimes, it is just learning to manage and work with what you have (so that might mean only planting in certain areas of your landscape or switching to certain plants that will thrive in whatever soil conditions you have). Remember: putting the right plant in the right place makes for more productive gardening which equals happier gardeners!
Management practices to improve your soil:
- Add organic matter, which helps aerate, provides nutrients, and increases water holding capacity. Compost is a great source of organic matter. You can make your own compost outdoors using kitchen and yard waste, or try indoor composting.
- Plant cover crops to make sure that your soil does not blow or wash away during the off-season from gardening. Did you know that it takes 500-1000 years to form 1 inch of soil (depending on the parent material)?
- Determine soil pH and keep it in the correct range for the specific crop that you are growing. (I will be diving into this topic on the blog next month—stay tuned!)
- Do not add soil amendments (fertilizer, lime, etc) without the guidance of a soil analysis. For information on how to take a soil sample, visit the Home and Garden Information Center’s webpage detailing soil sampling and how to select a soil testing laboratory.
- Create an environment that is attractive to soil organisms (limit or eliminate pesticides).
- Limit tillage practices. Try no-till or no-dig gardening.
Remember that if you take care of your soil, it will take care of you!
This year, the University of Maryland Extension Master Gardener Grow It Eat It Program celebrates the resource that supports all life on earth – soil! Look for soil education programs offered by your local Master Gardener program, and visit the Home & Garden Information Center website for more information about soil health.