Beets need full sun to grow the best roots, but if you don't have a sunny spot in your garden, you can still produce lots of delicious beet greens in partial shade. Beets grow best in loamy, slightly acid soils with a pH ranging between 6.0 and 7.5. If your soil is heavy clay, rocky, hard, or alkaline, mix in an inch or so of compost before planting. Add a bit of wood ash, if handy, because its rich supply of potassium enhances root growth. Beets aren't fond of crowds, so when sowing the seeds, plant them about 1 inch deep and 3 to 4 inches apart, or sow them closer together and use the thinnings later in salads.
Beets are adapted to grow in cool temperatures, so it’s best to plant them in spring or late summer. They thrive when the days are warm (60 to 70 degrees) and nights cool (50 to 60 degrees). For a spring crop, plant beets as soon as the soil dries out and is workable, typically in March. Where the weather remains cold and wet into spring, wait until April. Row cover can come in handy for spring crops, since beets may go to seed if temperatures drop below 50 degrees for an extended period and then warm up again. For a fall crop, plant beet seeds directly in your garden about eight to 10 weeks before the first expected frost and harvest them in time for the holidays. Fall beets are often sweeter because the cooler temperatures as they size up result in higher sugar levels.
As your beets grow, make sure to keep the area consistently watered, but not soggy. It’s a good idea to spread a layer of mulch around your beets to help keep the soil moisture consistent, which will help the plants grow more uniform roots. As the expected harvest date approaches, watch for full-sized roots. If you see the “shoulders” of your beets pushing up above the soil surface, they’re probably getting close to ready.
Beets (Beta vulgaris) are wind pollinated, and should be isolated from other varieties of beets and Swiss chard (which is the same species) by one mile to ensure pure seed. They are biennial, meaning they must overwinter in order to flower in their second year. In warm climates, this can be accomplished by simply leaving the beets in the ground and covering them with a generous layer of mulch to keep the roots from freezing. In colder climates where the ground freezes, the roots should be brought inside for storage and then replanted outdoors in spring. To store roots for replanting, cut the tops back to about 3 inches, pack the roots in sawdust or sand, and store them in a cool location with moderate humidity, such as a basement or root cellar. Replant them once the soil is workable again in spring, burying the roots so that the crown is at the soil surface. Save seed from at least six different plants to ensure good genetic diversity, and make sure to select the ones with the best root color, shape, and vigor.