Gardening Vivian | 02 Jul 2011 09:13 am

Does Soil Type Really Matter?

We all know plants need soil. But what is the function of soil for plants?

My students performed a little experiment in class to find out how much soil a plant uses in growing. They were surprised to find out that the soil mass really didn’t change. Their conclusion was “plants do not get their mass from the soil.” So, is soil just an anchor for plants? No, soil does provide nutrients for plants. Some plants need more nutrients than others. Lettuce for example can be grown in just water and do pretty well. (And taste pretty good, too.) Try that with tomatoes. Results are not quite as satisfactory.

Sure, tomatoes can be grown with hydroponic techniques. However, additives have to be mixed with the water to get good results. The mixture has to be tested regularly. Gets to be quite a hassle. What is the difference in soil? There are several differences. Soil can be clay, sand, or silt. Generally it is a mixture of the three. None of these soil types have all the nutrients plants need. Soil is simply a mixture of rock pieces and some plant and animal debris. “Rich” soil has plenty of humus. Humus is organic debris that comes from decaying plants, animals, and animal feces. Mixing this with the above soil types increases the “quality” of the soil. Some plants need to be in a well-drained medium. Mixing sand into the soil along with humus provides the drainage needed for the plants. Many flowers need a well drained soil type.

Most plants can not live in a clay soil. The clay doesn’t allow for any drainage and either rots the roots or holds the roots too tight when the soil dries out. If your soil is a clay soil mix a little sand, humus, and compost to the clay. This will cause the clay to clump into small balls so that it becomes workable and drains well. Once you have done this you will have a great garden. Sand is a great draining soil. However sand will move every time there is a rain storm. Sand will not hold water at the surface area, but will at deeper levels. Sand needs plenty of humus.

Loam is the best mixture for soil. It contains all three types of soil: clay, sand, and silt. Add compost and humus and you have the best possible mixture. Few plants will not grow in this type of soil. The compost and humus ensure all the right nutrients for the plant. This is important for healthy plants, but especially important if the plant is intended for human consumption. Adding commercial fertilizer is an option, but not recommended if you are trying to grow organic produce. What kind of plants do best in loam? Just about any plants. Tomatoes, squash, cucumbers and melons are just a few examples of vegetables that do well in loam. Whether the loam be a clay loam or a sand loam both will provide a the drainage needed for most vegetables. Even flowers like a well-drained area to spread their roots.

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