This pH meter is suitable for measuring the acidity of soil in a pot or in the open ground. Insert the measuring rod for ¾ into pressed and moist soil. The needle will display the acidity of the soil after 60 seconds. A pH of 7 is neutral and this is where your plants will grow well. If the pH is less than 5.5 then the soil is too acidic, and you can add lime to regulate the acidity. The size of this pH meter is 280x52x37mm.