Sowing: Large leaf sorrel seeds can be started indoors 3-4 weeks before the last spring frost. Sow the seed thinly 1/4” deep and press the soil down slightly to ensure good contact; germination should take place within 21 days. Transplant the seedlings in rich, well draining soil and full sun or partial shade after the last chance of frost, placing them 12-15” apart in rows 18” apart.