Cu den do, Table Beet, Garden Beet, red Beet Seeds, Dinner Beet, Golden Beet Seeds. Uniform and smooth, with blood red flesh that is sweet and tasty. 14" tops make good greens. Heirloom. Detroit Dark Red Beets are an extra deep dark red throughout. Good for greens, a fine bunching beet midseason and unexcelled for winter storage. Matures in 58 days. How long does it take for beet seeds to sprout? When sowing beet seeds indoors, you’ll typically find they take about 5 to 7 days to sprout. How do you plant beet seeds indoors? Indoor seed sowing results in a harvest that is 2 to 3 weeks ahead of direct sown beet seeds. Sow beet seeds from mid-spring through late summer planting them. When the soil has warmed to 50 F (10 C), direct sow beet seeds in a prepared garden bed. This is usually 3 to 4 weeks before the last expected spring frost date. Sow the seeds 1 inch apart and a 1/2 inch deep. Space rows 12 to 16 inches apart to ensure plenty of room for the beets to size up.