When starting seeds or planting seedlings the soil temperature should be considered. Here is a good guideline for soil temperature for seed germination from the University of California. Kansas State University horticulture expert Matt McKernan says gardeners can take their own soil temperature measurements using a soil thermometer, and measuring the soil at least 2.5 inches deep during late morning.

Find the average soil temperature over five days to determine when the time is right for planting.