Growing Guide When to Plant Amaranth Seeds Amaranth can be planted inside or outside in the Spring, but we?d recommend starting the seeds indoors 6-8 weeks before your last frost. If you decide to plant outside, wait until the soil is warm. Amaranth needs full sun and can be grown in almost any well-drained soil besides dense clay. Where to Plant Amaranth Seeds Amaranth needs full sun and can be grown in almost any well-drained soil besides dense clay. How to Plant Amaranth Seeds Amaranth seeds require light to germinate, so be careful not to cover them when planting. Plant your seeds about 10-12 inches apart and cover lightly with soil. They will germinate within 3-4 days if the temperatures are between 60-90 degrees F. When moving your seeds outside, sow them 1.5 to 2 feet apart. Amaranth is drought and heat resistant, so it is only necessary to water once or twice a week during dry periods. How to Harvest Amaranth Amaranth will flower until the first hard frost, so there will be plenty of seeds to harvest! Seeds from the flowers are usually ready for harvest after 3 months. To harvest, shake the flower heads and catch the falling seeds. Buy Seeds Online Organic Seeds Heirloom Seeds Non-GMO Seeds Vegetable Seeds Flower Seeds Herb Seeds Fruit Seeds Garden Seeds Seed Starter Kits Rare Seeds Bulk Seeds Indoor Gardening Seeds Seed Catalog Seed Packs for Sale Sustainable Seeds Greenhouse Seeds Seed Suppliers Planting Seeds Home Garden Seeds