2009-07-02 / News

Great gardens begin with great soil

The Island Garden
By Roger Marshall

Recently, I was asked, “What is the most important part of making a new garden?” I replied that the soil was the most important part of any garden. After all, plants won’t grow well in sand, rocky ground or poor soil such as clay.

“But how can you upgrade the soil?” was the next question. Start with a soil test; you can get one from URI Cooperative Extension at http://www.uri.edu/ce/ factsheets/sheets/soiltest.html. A good soil test will tell you not only what your soil has, but also what it lacks.

Armed with the results of your soil test, you can set about improving it. You may need to change the soil’s content or its acidity. For example, heavy clay soils don’t drain well, so they will need sand to help drainage and lots of organic matter to help water retention and bring nutrients to your plants. Light, sandy soils drain exceptionally well, but the lack of water allows them to dry out quickly and your plants will wilt. Changing soils in this manner can also take years.

One of the easiest ways to improve your soil is to add organic matter in the form of well-rotted compost. Well-made compost contains few seeds – most have been cooked in the composting process. Compost helps clay soil break down into a less-gooey mix. It helps sandy soil retain more moisture and provides a good nutrient base for plants to grow.

If you are starting a new garden bed, you can also sheet compost. That is, compost in situ. It takes a little longer, but is much easier on your back because you donít have to turn the compost. To sheet compost, put several layers of newspaper or cardboard down over the area where you want to make your growing bed. This will help to smother weeds and grass. Put a layer of seaweed or straw over the cardboard. Then, add a layer of leaves, a layer of grass clippings, a layer of finely ground wood chips, and more grass clippings or horse manure. Basically, you should alternate layers of carbonaceous material with high nitrogen material. Keep adding layers until your bed gets about 18 inches to two feet high, then top it with a layer of screened loam. If you don’t want anything to grow in the loam, cover it with mulch.

Leave the area for a few months to a year. You’ll notice that it sinks down to about two-thirds of its original height. Dig it over and plant in it. You might want to add more nitrogen-rich grass clippings, horse manure or a generalpurpose fertilizer, but your plants will love their new bed and you will have made it with little work.

Your soil’s acidity also plays a large part in plant growth. In Jamestown, most soils tend toward acidic. This acidity is also enhanced by rain. Acidic soil is good for plants such as rhododendrons, blueberries, azaleas and blue hydrangeas. (Hydrangeas turn pink in alkaline soil. To turn them blue, throw coffee grounds around them or add acidic fertilizer.) But acidic soil means that plants that like alkaline soil are difficult to grow. Plants such as carnations (pinks) and clematis prefer alkaline soil and need to be limed each spring to help them grow well. Lawns also prefer alkaline soil, so most gardeners add lime to the lawn in fall. The lime breaks down over the winter and helps the grass take up more nutrients (in the form of fertilizer) in the spring.

For an organic gardener, keeping your soil in tip-top shape may not seem like something you need to work on, but without good soil, it is difficult to grow good plants. Of course, you can ignore everything ‘íve said above and do as often suggested on television. Simply set out your plants with a dose of fertilizer and fertilize them often (using, of course, the fertilizer advertised) and you will have a wonderful garden--but also one that has poor soil that washes away in heavy rains.

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