CORVALLIS-Beets are best planted as early as you can get into your garden, starting in March or April, about two to four weeks before the last killing frost in your area. Plant beets successively at three to four-week intervals into July and you will have a continuous supply of fresh, tender beets until autumn. Beet seeds are best planted an inch or two apart, in rows 12 to 18 inches apart. Each seed is actually a dried fruit or seed ball, containing several tiny true seeds.