Plant globe amaranth after frost, or start seed indoors 6 to 8 weeks before the last frost. Soak the seed overnight and keep the tray warm.
Plant after frost, and start seed 6 to 8 weeks indoors
| Factor | Recommended | Avoid |
|---|---|---|
| When | After the last spring frost, once nights stay warm | Setting tender plants out on a freezing night |
| Seed | Soak overnight; sow about 1/8 inch deep at 70 to 75°F | Burying seed deep in a cold tray |
| Spacing | About 8 inches for longer cut stems, or 12 to 18 inches in a bed | A jammed row with no air around the plants |
| Pinch | Pinch young plants for a bushier mound | Expecting a tight mound from un-pinched, crowded stems |
Wait until frost is done and the soil has warmed. A cell-pack from the nursery is the easy start. Seed works if you keep it warm and sow extra, because germination can be uneven. [1] globe amaranth and Gnome Pink take that same after-frost set. Pick the habit on Types of Globe Amaranth.
When should I plant globe amaranth outside?
After frost, once nights stay warm. Do not set it out on the first mild afternoon.
How to plant globe amaranth
Start seed warm, or set a six-pack after frost at the same depth as the cell, then water to settle.
- Wait until after frost. Cool soil stalls the plant for weeks.
- Soak seed overnight. Sow about 1/8 inch deep and keep it at 70 to 75°F. Seedlings can take two to three weeks. [2]
- Start indoors 6 to 8 weeks before the last frost, or sow outside after frost. Sow more seed than you need, because germination can be low. [3]
- Harden off, then set transplants at the same depth as the cell. Space about 8 inches apart for longer cut stems, or 12 to 18 inches in a bed. [4]
- Pinch young plants so they branch. Cut-flower rows often skip that pinch and space closer instead.
- Water to settle. Sun and later watering stay on How to Grow Globe Amaranth.
Can I start globe amaranth from seed?
Yes. Soak overnight, keep the tray warm, and sow extra. Or buy a six-pack after frost.
What fails at planting
Planting too early in cool, wet soil is the main reason seedlings stall. Do not bury the seed deep, and do not skip extra seed when germination is uneven.
If seedlings stall, the soil was still cool — wait for warm nights and start again.
FAQ
Can I plant a six-pack instead of seed?
Yes. A nursery six-pack is the easy start. Set it out after frost at the same depth as the cell, then water to settle.
Related guides
Recommended plants
References
- [1] Clemson Cooperative Extension HGIC -
https://hgic.clemson.edu/annual-globe-amaranth-gomphrena-globosa-in-south-carolina/ - [2] Wisconsin Horticulture -
https://hort.extension.wisc.edu/articles/globe-amaranth-gomphrena-globosa/ - [3] NC State Extension Gardener -
https://plants.ces.ncsu.edu/plants/gomphrena-globosa/ - [4] Johnny's Selected Seeds -
https://www.johnnyseeds.com/growers-library/flowers/gomphrena-globe-amaranth/gomphrena-globe-amaranth-key-growing-information.html
This note is part of Gomphrena Guides.
More planting notes by plant are gathered in Planting Guides.
Updated: Reviewed by Bosquelle Editors