Dig Up Some Dirt
The ABCs of Soil
article by P. Allen Smith
A bountiful garden, like most things in life, begins with a solid foundation; and, soil is the key to a garden’s foundation. I find all gardens can benefit from some tender loving care before planting.
Before getting out your garden spade and planting, you need to know the basics about soil. A good first step is a soil test. A soil test conducted by your county cooperative extension service provides information about the soil, including nutrients available in the soil as well as the pH, or acidity, of the soil. Soil can range from acidic to neutral to alkaline. Most garden plants thrive in soil that is more neutral than too acidic or too alkaline. Test results provide plant food and fertilizer needs, taking the guesswork out of what you should or shouldn’t add to the soil. If you’re going to plant in different areas of the yard, for example plants in the front and vegetables in the back, do a soil test for both areas. Soil composition can vary in different areas, so don’t assume that the front garden needs are the same as the backyard needs. Keep in mind it takes time to build healthy soil, so consider testing in the fall prior to spring planting, so you have plenty of time to get the soil in shape.
It’s also important to know the texture of the soil; is it sand, clay or silt? Knowing the texture of the soil gives you a good idea of how well the soil holds and retains nutrients. To determine texture, take a golf ball-size lump of soil—if it falls apart, it’s too sandy. If the lump holds its shape, it has too much clay. A good soil is comprised of different sized particles that allows for water and air to flow freely and create an inviting environment for microorganisms.
If you notice pools of standing water in the garden, don’t blame it on the rain; rather, blame the soil. Most plants, including vegetables, thrive in well-drained soil. To check drainage, dig a hole one foot deep, fill hole with water, then let it drain. Refill the hole with water and measure the depth, then measure again 15 minutes later. Multiply that number by four to measure how much water drains in one hour. The desirable range is one to six inches of drainage per hour.
Once you get the soil test results and determine the texture, you’re ready to get your hands dirty and start improving the soil. I always like to take a few minutes to really feel the soil in my hands and between my fingers. This helps me connect to the earth and prepare for my gardening task at hand. First, add organic materials. Organic matter can help a soil that is high in clay drain better, or it can help a highly sandy soil retain moisture. Compost is a great organic material for this step. You can also use a covering of grass clippings, leaves, straw or wood chips—shop your yard for materials already available to you. Make sure all vegetation, including weeds, has been cleared out first.
Next, add fertilizer and lime as determined by the soil test results. Be sure to only apply the recommended amounts and not more. We sometimes think if a little is good, more will be better; this is not the case with fertilizer. Be mindful of what you put into the soil just as you’re mindful about what you put into your body.
Be careful not to work the soil with hand tools or tillers while it’s wet. Working the soil, or even walking through it while it’s wet can lead to compaction. Use stones, bricks or other materials to create a pathway that’s both attractive and allows for digging in the garden without compacting the soil.
Maintaining the soil
Don’t let your hard work go to waste—make sure you maintain the health of the soil throughout the year. Microbes digest and burn up organic matter in the soil, so you’ll want to continue adding organic matter to keep the soil healthy. If you’re planting a vegetable garden, consider planting a cover crop such as annual ryegrass, clover or winter rye. Cover crops protect the bare soil after you harvest vegetables. Then, before the next planting, you can till the cover crops into the soil as another source of organic matter. Earthworms and other critters living in the soil naturally feed plant roots by pulling composted material into the ground, and mulch helps prevent weeds and facilitate moisture retention.
I find my cares really melt away, when I get some dirt under my nails. I hope these soil foundation tips get your soil in tip-top shape, so you, too, can find relaxation in your garden.
A Living Community
Healthy soil is packed with microorganisms, most of which are invisible to the naked eye. Two of the most beneficial bacteria are mycorrhizal fungi and rhizobia. Mycorrhizal fungi are tiny fungi that attach to roots and facilitate movement of water and fertilizer. They also help plants withstand environmental stress, including drought or dry winter weather.
Rhizobia form nodules on the roots of host plants supplying plants with nitrogen. Plants, in turn, supply the bacteria with essential nutrients.
Earthworms are a gift from Mother Nature and a sign of healthy, fertile soil. As they burrow their way through the soil they loosen up the soil, making way for air and moisture.
There are a few steps you can take to encourage the development of beneficial organisms:
• Effective watering—these bacteria require a damp environment
• Adding organic matter and organic mulch—to provide food and maintain the damp environment
• Avoid excessive roto-tilling—excessive roto-tilling can destroy the bacteria
• Avoid plastic sheets under rock mulch—the plastic limits water and air movement discouraging microorganism activity