Seed Depth: 1/4–1/2 inch

Seed Spacing: 18–24 inches

Row Spacing: 24–36 inches

Sunlight: Full sun

Days to Sprout: 10–21 days

Days to Maturity: 60–120 days (depending on the part of the plant harvested)

Growth Habit: Upright, bushy annual or biennial

Sunlight: Requires full sun, with at least 6–8 hours of direct sunlight daily.

Soil Type: Thrives in well-drained, sandy, or loamy soil with a pH of 6.0–7.5. Enrich with compost for better growth.

When to Plant: Sow seeds directly outdoors in early spring or late summer. Milk thistle is tolerant of cooler weather.

Direct Sowing: Plant seeds 1/4–1/2 inch deep, spacing them 18–24 inches apart in rows 24–36 inches apart.

Indoor Sowing: Start seeds indoors 4–6 weeks before the last frost and transplant seedlings when they are 4–6 inches tall.

Succession Planting: Not typically needed; plants self-seed and return yearly in suitable conditions.

Watering: Water deeply but infrequently, allowing the soil to dry out slightly between waterings. Milk thistle is drought-tolerant once established.

Fertilizing: Not typically required, but adding compost at planting can boost growth in poor soils.

Pruning: Remove spent flowers to prevent excessive self-seeding if control is desired.

Pest and Disease Control: Generally pest-resistant but monitor for aphids and fungal diseases. Use organic solutions if necessary.

When to Harvest: Harvest seeds when flower heads dry and fluff begins to form, typically 90–120 days after planting. Leaves can be harvested earlier for fresh use.

How to Harvest: Cut flower heads and allow them to dry completely before separating seeds. Use gloves to handle spiny plants.

Seed Collection: Once flower heads are dry, remove seeds and clean them of fluff and debris.

Storing Seeds: Store seeds in an airtight container in a cool, dry place.