HOW TO USE A MOISTURE METER:
Hold the Gauge end of the meter in your hand and gently insert the probe into the plant pot 1/2 - 3/4 of the way down into the soil.
Be gentle not force the probe in as this may damage roots.
Read the gauge: if it displays dry or is at 1 or 2 it may mean your plant needs water, however, some plants such as succulent, cacti and some leafy indoor plants, like Dragon trees, prefer to dry out and need to reach the yellow zone, just past 1, before watering.
Most general houseplants prefer moderate moisture and will be happy if kept at the level between 5 and 6.
Ferns and other more moisture-loving plants prefer to stay at the level between 7 & 8.
If your soil shows 9 & 10 this is a sign that it may be waterlogged, unless just watered.