Different varieties of plants require different soil temperatures to germinate.
Every seed is an embryo of a plant. Some seeds can stay in the embryonic stage for years, until conditions are right for it to germinate…that is, begin to grow into a plant.
A seed will begin to germinate when the soil has reached the proper temperature, and when the right amount of water and oxygen are available.
The seeds of some plants will germinate within a specific temperature range. However, seeds germinating at the lower end of that range may take longer to mature than those germinating at the higher end.
Others plants, like desert and prairie wildflowers, will germinate only when the soil reaches a specific temperature.
Also, the optimum soil temperature will vary widely in various species and varieties of plants.
Vegetables planted in desert gardens require various soil temperatures to germinate. For instance, snap beans, cucumbers and tomatoes need a soil temperature of 60 F, while sweet corn, lima beans and mustard greens require 65 F.
Squash, watermelons and peppers need 70 F, while okra, cantaloupe and other plants need 75 F.
To find out the temperature of your soil, you can purchase a soil temperature thermometer from your local nursery or garden supply, from an online company or from a catalogue.
Your local cooperative extension service, master gardeners’ or agricultural university can provide you with information on optimum temperatures for germinating seeds of specific plants and varieties.
