By our calculations, you should look at sowing Bloomsdale Savoy about 60 days before your last frost date.
It is best planted in early spring and fall. If fall-planted, it will overwinter and produce much earlier than if it is spring-planted.
Ensure that temperatures are mild (minimum night temperatures should be around 0°C / 32°F) and all chance of frost has passed before planting out, as Bloomsdale Savoy is a half hardy plant.1 http://www.westcoastseeds.com/productdetail/vegetable-seeds/Spinach/Bloomsdale-Savoy-Organic/