How to Plant Spinach in Zone 8. Spinach is a cool-season crop, thriving in areas with cool, moist weather. This nutritious leafy vegetable turns bitter and produces seeds and flowers when temperatures rise above 70 degrees Fahrenheit. Gardeners living in U.S. Department of Agriculture hardiness zone 8 -- which includes parts of Georgia, South Carolina, Alabama, Mississippi, Louisiana, Texas, Arizona, New Mexico, Nevada and California -- grow spinach in early spring or fall, when temperatures are moderate and rain is more likely.
Select a location for growing spinach that receives morning sun and partial afternoon shade, especially if you wish to grow a spring crop. Partial shade will keep the spinach from bolting (going to seed) as quickly as temperatures rise. Dig 2 to 3 inches of compost or manure into the soil to add nutrients and improve drainage and texture.
Plant the seeds 3/4-inch deep and spaced 1 inch apart in rows 12 to 18 inches apart. Spinach germinates best when soil temperatures are between 40 and 75 degrees F. It fails to grow when temperatures are warmer. In zone 8, plant spinach between Jan. 15 and March 15 for a spring crop or between Sept. 1 and Oct. 15 for a fall crop.
Thin the plants to stand 2 to 3 inches apart when the spinach is 3 inches high. Overcrowding may stress the spinach, causing it to bolt prematurely.
Water the spinach every two to three days during dry conditions to keep the soil evenly moist. Dry soil causes spinach to turn bitter and go to seed. Lay a 2-inch layer of wood chip or straw mulch around the plants to conserve moisture and keep the soil cool.
Harvest the spinach 40 to 45 days after planting, depending on the variety, when it stands at least 4 to 5 inches high. Cut spinach at the base of the plant with scissors for multiple harvests.