spinach is most successful during the cooler days of spring. Spinach seeds
germinate best in soils between 55 and 65 degrees, says Deborah Kean, Oregon
State University vegetable crops researcher.
you plant spinach in the summer, some varieties will flower, or “bolt.” They
stop growing leaves and set seed. Kean and her colleagues at OSU have grown
various spinach varieties and found one that seems to best tolerate long days
and heat without bolting—Correnta.
matter where you are in the maritime Northwest, plan on planting broadleaf
spinach about four to six weeks before your average last frost in the spring,
and six to eight weeks before the first frost in the fall. From late spring
until mid-summer, plant the heat-adapted spinaches.
a continuous supply of spinach, plant seed every one or two weeks. Sow cool
season spinach in the early and mid-spring. Plant Correnta in late spring and
through summer. Then follow with more plantings of cool season spinach.
For more info,
download OSU Extension’s “Grow Your Own Lettuce, Spinach and Swiss
Chard,” at: http://extension.oregonstate.edu/catalog/html/ec/ec1268/