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Testing Your Soil

 See Also: Soil pH for Vegetables


Are you only having mediocre results with your lawn, vegetable garden, flowers or shrubs? If so, chances are you need to have your soil tested so you know exactly what is needed to properly grow your plants.

There are several different ways in which you can have your soil tested. One is to use a do-it-yourself home soil test kit. Soil testing services are also provided by the Washington State University Cooperative Extension Service, or by private laboratories. Both the private laboratories and the Cooperative Extension Service charge a small fee for soil testing. The actual fee depends upon the extent of the soil tests. Forms and information for the Washington State University Cooperative Extension Services are available through your local county extension service. You will find them listed in the white pages of your telephone directory under county government. Depending upon the season, it will take from one to three weeks for results.

If you want to test your own soil, you can easily do it with a soil test kit. Most garden outlets feature soil test kits, such as the one sold by Sudbury Laboratory of Sudbury, Massachusetts.

A good soil test is essential because it lets you know the specific nutrient needs of your garden so you do not waste money on the wrong fertilizers. The soil test will also let you know whether you need to raise or lower the pH of your soil. Careful soil testing and correction of the soil to the specific needs of your garden assures that each crop gets exactly what it needs to grow and yield to its fullest potential.

Here is why it is necessary that you know the soil pH, the nitrogen, phosphorus and potash content in your soil.

pH - Soil pH is the factor which determines whether or not plants are able to consume nutrients. If the pH is too high or too low, nutrients in the soil "lock up", become unabsorbable by the plants, thus fertilizer not only goes to waste, but your plants literally starve to death.

NITROGEN - Adequate nitrogen produces luxuriant growth of stalks, stems, leaves, and grasses. Excessive nitrogen causes too rapid growth that results in softness of tissue and general plant weakness. Plants suffering from nitrogen deficiency are more susceptible to disease, infection, and injury. Plants given too much nitrogen resume active vegetable ("green") growth which retards flower and seed formation.

PHOSPHORUS - Phosphorus gives plants a rapid start, stimulates root formation, hastens maturation, aids blooming and seed formation.

POTASH (POTASSIUM) - Proper amounts of potash stimulate early root or tuber formation which is essential for all underground vegetables and tuberous flowers. Excessive potash reduces a plant's resistance to droughts and frost injury and delays plant maturity.

HOW TO GATHER SOIL SAMPLE - Gather a soil sample from two to three inches below the surface using a clean instrument such as a soil sampler, trowel or spoon. Since test results are sensitive to external factors such as ashes, never smoke while gathering or testing your soil and avoid touching the sample with your hands.

Put samples in clean containers and label according to which part of the garden they were gathered from. Samples should be taken from various areas, especially when there is a change in the elevation of the land or where there might be a variation in the soil (a particularly sunny spot, an area beneath a tree, a part of your garden that has been under cultivation, or low-lying areas which collect water). It is best to take samples from each corner and the center of the plot in any case.

The soil should not be too wet. If it is not dry enough to walk on, allow it to air dry naturally rather than over direct heat.

Remove solids and debris such as stones and pieces of wood WITHOUT TOUCHING THE SOIL. Crumble soil as finely as possible. This is easily accomplished by putting the sample in a plastic bag and crumbling or going over it with a rolling pin. Your sample is now ready for testing.

Soil test kits, such as the Sudbury kit, include valuable charts listing the ideal pH for hundreds of flowering plants, vegetables, grasses, and trees, plus, charts illustrating how to determine exact nutritional needs after testing, instructions on how to raise and lower pH, and instructions on when and how to fertilize.

With a properly fertilized lawn and/or garden, with the soil adjusted to the correct pH level, you should have little problem growing beautiful flowers, the juiciest, most nutritious vegetables, or the thickest, greenest lawn in town.


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