It’s already the middle of March and I’m worried that our soil is still too cold to plant peas (both edible and sweet). When is the correct time to plant them in the Seattle area?
Since weather patterns vary from year to year, it may make more sense to plant based on something other than the calendar date. An old adage says that it is time to plant peas when the lilac leaves are the size of a mouse’s ear. This may sound quaint, but it turns out that the growth cycle of the lilac (Syringa) is an excellent indicator of temperature. Phenology is the science concerned with the timing of specific biological events, and lilac is among the plants often studied. Project BudBurst has additional information about phenology and climate change. The U.S. National Phenology Network is also a good resource.
If you don’t have a lilac in your garden (or a mouse’s ear, for that matter), Washington State University Extension (link no longer available) says that a safe time for planting peas is usually mid-March, not so much because of soil temperature, but because in February the soil is often oversaturated, and your peas would rot in the ground.