Soil BasicsWhat is this stuff we call soil? It's not dirt, that's what you bring into the house. Knowing about the content of your soil or its composition is an important first step to understanding why things grow well in your garden or why they don't. Before you can have great expectations for plants and vegetables a review of what is in your soil will be helpful. Soil is a combination of mineral substances or particles formed from the gradual breakdown of rocks, nutrient-rich decaying organic matter, micro-organisms, water and air. All these components are inter-related and make soil a growing fertile environment with signs of life and activity within it. All soil is not created equal. Good soil is rich in color and crumbly when you rub it in your hands, it feels granular yet pliable as you work it in the ground. Sand, silt and clay particles give soil its texture. It needs air for circulation and drainage so water doesn't clog the particles or wash them away. Soil is generally categorized into three groups: sandy, loamy and clay. Ideally your soil will be a mixture of all three but in many instances you will need to 'amend' the soil with organic material or humus to improve its structure. A clay soil is pretty obvious. When you dig into it the soil is heavy to the touch and dense in appearance. When it rains the soil is slow to dry out and because of its denseness it doesn't quickly absorb light and heat from the sun. If you walk through a field or yard with crater like cracks or ruts it's likely to be clay. It can form a hard crust when left alone making it almost impenetrable. A sandy soil is the exact opposite. Rain and sunlight pour through a sandy soil because its light granular texture acts like a sieve. A loamy soil combines the best features of both clay and sand with humus. Humus is decayed organic matter that improves the structure and the texture of soil. Humus allows soil to retain water and absorb the sun which stimulates plant growth. Soil Test Have your soil tested to find out if it is unusually acid or alkaline. The test will tell you the pH level of the soil - the degree of acidity or alkalinity. A neutral pH is 7.0. Soil with a slightly acid pH level of 6.5 is good for both flower and vegetable gardening. The test will also provide a breakdown of how much magnesium, phosphate and potash the contains. an analysis of the texture of the soil - sandy, loamy, silty, or clayey, and specific recommendations to enhance it. For example, for a typical flower garden soil with a 6.5 pH it suggests adding fertilizer 20 pounds per 1000 square foot. Local county extension services across the country offer this service for a very reasonable amount, sometimes as low as $5. Look up your county agency under "county government" in the Blue Pages of Government Listings in your telephone book. There will be a listing of your local cooperative extension service. Ask for a soil test kit which is usually a preprinted mailer and box or sack (for the soil sample). Don't combine lawn and garden soil samples together. It's better to submit two separate soil tests and label them either 'lawn' or 'flower garden' or 'vegetable patch.' To get a sample of your soil use a spade or shovel to dig down about 6 inches in a garden and 2 inches in an established lawn. Dig out several examples of soil from throughout the garden or lawn so you'll receive an overview analysis of the entire soil. Pile all the samples together, mix them up and let them air-dry. Do-it-yourself Soil Test You can test your soil using a clear jar with a lid. Fill the jar half full of soil from your garden then fill the remainder of the jar with water. Tighten the lid and shake it up to mix the soil with the water and let it sit overnight. The next day there should be four layers of soil. On the bottom is sand, silt is in the middle and clay is on top. Organic matter will probably float on the top of the water or settle into the top of the clay layer. Look at the layers in the jar and compare it with the Illustration which shows a good nutrient rich soil. Add peat moss and/or compost to loosen heavy clay soils or to give body to a sandy soil. Then retest the new soil mixture to see if you've achieved the optimum mix containing at least 20% organic matter. written by Gene and Katie Hamilton
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