Soil Testing
Apr 30 | Garden Soil
Lime or sulfur can be safely applied to the soil at any time. Work them into the soil before planting or side-dress existing plants. Since soil pH will slowly revert to its original level before treatment, it’s a good idea to test your soil every two years. You can have your soil’s pH measured by a university laboratory through your local cooperative-extension service or use a soil testing kit from garden stores or catalogs. The lab test report or kit instructions will give suggestions on how to raise or lower soil pH. Lab reports will list your soil’s resistance to pH changes based on the structure of your soil. This is referred to your soil’s buffer pH. If your soil is sandy and well drained you can raise the pH a full point in one season. Heavy clay soils will take more lime and a longer time for the same amount of change in the pH level.
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Understanding Soil pH
Jan 11 | Garden Soil
What do the p and H in pH stand for? And why is a proper pH level in your soil so crucial to plant growth? The “p” is a mathematical operator like “+” or “x”. In chemical mathematics, “p” means “the negative logarithm of something”. In the case of pH, it would be defined as “the negative logarithm of the concentration of hydrogen (H) ions in the soil.”
Soil pH simply measures how many hydrogen ions are affecting plant roots. The more hydrogen ions present in the soil, the more acidic the pH. The pH scale ranges from 1 (extremely acid) to 14 (extremely alkaline). At pH 7 (neutral), hydrogen ions have little effect on the plant’s root ability to absorb nutrients. Scientists have found that plants generally need a small amount of acidity in the soil for optimum growth. The roots seek out the major soil nutrients: nitrogen, phosphorus, and potassium absorbing them for healthy flower, leaf and root development. Some ions are dissolved in water making uptake by plant roots simple. Some cling tightly to particles of clay and humus so the plant roots have a harder time absorbing them. Calcium loosens nutrient ions from the soil particles, making fertilizer more available to plant roots.
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