(3/14) Soil is a marvelous substance. If we had a chance to play in a backyard when we were growing up, we would probably understand this. We found all sorts of creatures living in it. When mixed with water it makes a fun substance called mud. If we were really lucky, there was a gardener in our life who let us dig with her and we discovered the unseen parts of plants, the roots. Discovered how much fun it was when someone helped us put bean seeds in the ground. Now, as adults, we understand that a major role of soil is to supply nutrients for those seeds to grow into plants.
Adequate soil nutrition is important for all plants, but for those of us growing plants to eat, a plant’s ability to take up those nutrients is especially significant. When you read the back of a bottle of vitamins and minerals, some of the listed minerals are calcium, potassium, magnesium, zinc, iron, and manganese. These are the same ones we call micronutrients. Have you thought about where a person got these minerals before they were available in a pill?
A century ago, most people ate a lot more fresher vegetables than today. Folks who didn’t live in a city grew their own food. Before refrigeration became available the source of most food for city people was from farms only a few miles out of town. Food was their source of dietary minerals, and the soil was the source of minerals which the roots take up to feed the plants which those people ate.
When a seed absorbs water under adequate temperature and light conditions, the nascent plant uses the store of minerals in the seed to begin life. As the seed germinates the young roots are using the minerals stored in the seed. When the first seed leaves, the cotyledons poke out of the ground and photosynthesis begins. The roots are now taking up the necessary mineral elements to make the biochemicals of life so that light energy can become the chemical energy, and enzyme machinery, needed for cell division and growth.
It’s pretty obvious, then, that soil minerals are necessary for plant growth to make food for people and other animals, to make flower gardens bloom with an array of color and texture, and to make fruit and seeds for propagation.
Another important consideration in soil nutrition is soil pH. That is how acidic or alkaline a soil is. A gardener who tried growing blueberries or rhododendrons in soil derived from limestone understands this. Some mineral nutrients are finicky about their availability to plants. Those minerals change their chemical nature depending on how acidic or basic the soil is.
Gardeners are also aware that as the minerals are used by the plants. The gardener removes the plants at the end of the season. The minerals those plants used, need to be replaced. The gardener decides how she is going to replenish soil fertility. Organic matter – compost, cover crops, slow-release organic fertilizers – are the best sources, especially for those needed in small amounts, the micronutrients. Bagged chemical fertilizers can be used to supply nutrients needed in greater quantities: notably nitrogen, phosphate and potassium. The N-P-K listed on the fertilizer bag. And slow-release organic fertilizers are the best choice for soil health.
But what does the garden or lawn need? And, is the pH of the soil at the correct level so the minerals are available to the plant? How do I find this out? The best way to find out what garden soil needs is with a soil test. Each garden needs its own test because the nutritional needs of a general vegetable garden, backyard fruit orchard and lawn are all different. You need a separate test for each garden you intend to grow. And even in a yard that’s less than an acre, you can have different soil types in different parts of the yard. The results you get tell you what nutrient levels are fine and what is lacking for your project, as well as your soil’s ability to hold nutrients.
The Penn State Extension has soil test kits that gardeners and farmers can purchase from the county Extension Office. The kit includes instructions on how to take the sample, forms to tell the lab what kind of garden you are testing and an envelope to send the sample to the state lab for testing. Since lawns, home orchards, flower gardens, vegetable gardens, and blueberries each have different needs, you need to have a separate test for each garden or lawn you want to test.
To get a good soil sample, follow the instructions provided with the soil test. Regardless of the type of garden you are testing, dig about 6 inches into the ground, grab a sample and put it in a container. Do this for ten samples in ten random spots and mix all the samples thoroughly. Be sure to remove large bits of organic matter and pebbles. I allow the sample to dry several days because the cost of mailing the sample is the responsibility of the gardener and moist soil is heavier than dry soil. Put about one 8 oz. cup of soil into the pouch provided. Be sure to fill out the proper form indicating what kind of garden or lawn you are testing! After you put the soil and form in the mailer provided, seal it and take it to the post office for shipping.
When you get the results, you can make the necessary adjustments needed to bring your garden nutrient levels up to snuff. If you find yourself befuddled by the results, help is available. Master Gardeners can answer your questions and the Hot Line is available through the winter from 10 am to 2 pm on Wednesdays, returning to Monday, Wednesday and Friday after April 1.
This winter can’t last forever. Let’s get outside and get into the soil.
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