Ground Temperature Salem Oregon
There is a great article entitled, "Is it time to plant vegetables? Ask your soil thermometer". In this article Annie Chozinski, Oregon State University vegetable researcher states:
"With a thermometer, no guess work is needed. Soil temperature is the best indicator of when to plant each type of vegetable, no matter what climate zone you live in."
A soil thermometer can be purchased at your local plant nursery.
Speciifc vegetables are cited in the article, from crops that germinate in the coolest soils to crops that are warm-season soils. Peas are discussed as being a crop that germinates in coolest soils, citing down to 40 degrees F. You can review the entire article at the following link:
To ensure success with early-season vegetable gardening, Chozinski advises buying cold-tolerant or short-season varieties.
All the best to you in your garden this year!