South Puget (Olympia) Sound Last Frost Dates

Thinking about planting? Here's a helpful post from last year to help you avoid frost for those sensitive crops.

South Puget (Olympia) Sound Last Frost Dates

Probability/confidence of noted date to be last 32F frost	10%	50%	90%
Date	April 17th	May 5th	May 23rd

Source: NDAA NCDC

Dates below are WRT 50% confidence last 32F frost dates

Crop	Start Indoors	Plant in Garden	Harden off?	Notes
Onion (yellow & red), chives, shallots	Feb	April-May	Yes	Trim onion starts to 3"-5" high to develop strong root system
Broccoli	Feb	March	Yes
Bell Peppers	Early March	May	Yes
Cilantro	March	May	Yes	Can also be directly sown in the garden.  Prefers cooler temps
Cauliflower	March	May	Yes	Can also sow directly in garden April thru June
Italian Kale	March	May	Yes	Can also sow directly in garden in May
Carrots	No	March - July	NA	Carrots have very sensitive roots and forking generally results from transplanting starts.  T(soil)>50F for germination, but tolerates colder temps
Tomatoes	Late March - early April	May	Yes	Start and transplant earlier if using greenhouse or row cover
Sugar Snap Peas	No	As soon as soil can be worked in spring	NA	Peas are very cold tolerant
Cabbage	No	April-June	NA	Germination requires T(soil) = 55F.  May-June sown crops will be ready in the fall
Red Potatoes	No	Mid April	NA	Sow seed potatoes up to 3 weeks before last frost
Spinach	No	T(soil)>= 50F	NA	Sow fall varieties in August and September
Basil	April	May	Yes	Direct sowing not recommended unless nighttime temps will not drop below 50F
Cucumber	April	May	Yes	Cucumbers have very sensitive roots.  Disturb them minimally when transplanting
Corn	April	May-June	Yes	Ideally corn is directly sown in the garden.  However, due to the short PNW summer, indoor starts are often necessary.  Be sure to minimally disturb roots when transplanting.

By Todd Morgan, Master Gardener