If a houseplant’s soil pH is too low or too high, it cannot access certain nutrients that are available ... "Insecticidal soap can help control aphids, spider mites, and mealybugs. Horticultural oils ...
This describes how acid or alkaline soil is, and is expressed as a number between 0 and 14. Soil with a pH of 7 is neutral, an acid soil has a lower value, and an alkaline soil has a higher one. Most ...