Garden Soil Temperature

http://www.durgan.org/URL/?FJMQH 9 April 2012 Soil Temperature
From observations of garden soil temperature over the last few years, it has been ascertained that the temperature about six inches deep is a good guide as to when to start plant seedlings and seed. Before planting I like the temperature to be in the range of 16C to 20C at about a depth of six inches. The temperature rises to about 22C at the heat hight of Summer and is usually around 20C in my area. The top 2 inches can get considerably warmer under a hot Sun. When the Sun is not present the soil temperature quickly assumes a constant 20C with no variation in depth. Pots and containers in a greenhouse can get dangerously warm and it is prudent to monitor them.The probe thermometer is very handy to monitor as required.