Q: I have a Luster Leaf 1618 Rapitest Soil Thermometer. I notice that when it is placed in a room it reads 10 degrees lower than my other thermometer. Why is this? It makes me distrust the accuracy of what I'm reading when it is in the soil.
To test the thermometer stick it in boiling water for a minute. Water boils at 212 degrees F. Warm the thermometer in a glass of very warm water first so the glass does not shatter. Adjust your reading accordingly. Best And Happy Yardening, Nancy