Flowers

How to Plant Globe Amaranth: Timing, Spacing, Care & Bloom

Quick answer

Start indoors 6–8 weeks before last frost (WI/Clemson/USU). Transplant after all frost danger / after last freeze (WI/USU). Not leaf or grain amaranth.

Globe amaranth at a glance

PlantStart indoors: 8–6 wk before last frost; Transplant: last frost
SunFull sun; warm-season; no frost tolerance (USU).
SpacingWI: about 8 inches apart after hardening off.
Days to bloomBloom season July–Oct. (Purdue HO-80)
-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Not leaf/grain amaranth: globe amaranth is Gomphrena (gomphrena) — a warm-season flower. Edible/grain amaranth is a different crop — see how to grow amaranth.

Globe amaranth
Globe amaranth (Gomphrena globosa). Photo: Forest & Kim Starr, Wikimedia Commons, CC BY 3.0 (resized).

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.

Planting timing

Wisconsin: “Sow seeds indoors 6 to 8 weeks before last frost. … Plant outside (after hardening off) about 8 inches apart after all danger of frost has passed.” (WI globe amaranth) Clemson: sow indoors 6 to 8 weeks before the last frost date. (Clemson gomphrena) USU cut-flower: sow 6 to 8 weeks before transplanting out; field transplant after the last freeze. (USU gomphrena)

Depth and spacing

WI: about 8 inches apart after hardening off.

Sun, soil and water

Full sun; warm-season; no frost tolerance (USU).

Care and bloom

Papery clover-like bracts summer through frost (WI). Good cut/dried flower.

Pests and diseases

Cultural warmth and sun first.

Related: leaf/grain amaranth · ZIP planner · Mexican sunflower

Frequently asked questions

When do I start?

6–8 weeks before last frost (WI/Clemson).

When outside?

After all frost danger (WI/USU).

Same as amaranth greens?

No — Gomphrena flower, not leaf/grain amaranth.

Sources