A Detailed Explanation of How Soil pH Affects Flower Growth

Soil pH is expressed by the pH value. The pH value<5.0为强酸性，pH值5.0～6.5为酸性，pH值6.5～7.5为中性，pH值7.5～8.5为碱性，pH值>8.5 is strongly alkaline. If the soil pH is unsuitable, it will hinder the plant's absorption of nutrients, because pH is related to the solubility of mineral salts. The availability of mineral nutrients such as nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, iron, manganese, molybdenum, boron, copper, zinc and others all varies with the strength of the acidity or alkalinity of the soil solution.

Measurement of soil pH: take a small amount of potting soil and put it into a glass, add water at a ratio of soil to water = 1:2, stir thoroughly, dip litmus paper or universal pH test paper into the clear liquid, and the pH can be determined from the change in the color of the test paper.

Adjustment of soil pH: when the acidity is too high, mix some lime powder into the potting soil or increase the proportion of plant ash (rice husk ash also works). When the alkalinity is too high, add an appropriate amount of aluminum sulfate (white alum), ferrous sulfate (green vitriol) or sulfur powder. When applying nitrogen fertilizer, use ammonium sulfate, which can also lower soil alkalinity and increase acidity. Fruit peels can also be used to neutralize alkaline potting soil; soak apple peels and apple cores in cold water and regularly water with this water to gradually reduce the alkalinity of the potting soil.