Give your seedlings a good start and avoid transplanting shock—check the soil temperature before planting. 
 
This Rapitest® Soil Thermometer provides readings in Celsius (-10 to 50° C) and Fahrenheit (17 to 120° F) to help you plant at safe and proper soil temperatures. 
Durable, corrosion-resistant, aluminum casing. 
Dimensions: 8-2/5" H x 2-9/10" W x 3/4" D.