Sowing: For a spring crop, direct sow the seeds 6-8 weeks before the last spring frost. For a fall crop, direct sow the seeds 6-8 weeks before the first fall frost. For smaller plants, plant a few seeds every 12" and1/4 deep; later remove all but the strongest plant. If you need bigger plants, space them 2' apart. For companion planting benefits, plant collards with tomatoes.