When the soil temperature hits 50 to 58 degrees, some of our favorite Spring mushrooms will start to pop. Throughout the United States, except for a handful vinsiwineform.com of southern states that are just too warm and dry, the Morel mushroom is about ready to harvest. As the soil temperature rises above 50 degrees the Morel quickly sprouts and reaches for daylight. You must be quick because within hours various bugs and other wildlife start to consume the dandy delight. As always with wild mushroom harvest..