I grew Gomphrena (globe amaranth) for the first time in 2023 and tested them out both in the landscape (Circle Garden) and in containers. They performed very well, with little pest damage and required little care, although Gomphrena is slow to get going and doesn’t really fill out until mid-summer. The plants in the Circle Garden also flopped over the edges a bit by the end of August.

This is my personal growing guide. I use it to track seed sources, when to start seeds and if I should adjust growing conditions in my own greenhouse and garden. Please don’t consider this professional grower’s advice. I like the plant information cards from Ball Seed – here is Gomphrena Gnome Mix.

FAVOURITE VARIETIES AND SOURCES

I prefer solid-colour varieties to bi-colour ones. In 2026 I’m using some left over seeds:

William Dam Seeds

• Audray Purple
• Audray Bicolour rose

Baker Creek

• Buddy Purple
• Lavender Lady

I won’t need this many but the seed packages are 2-3 years old so I’ll over-sow and see what I get.

Notes:

Gomphrena is slow to get going, both as seedlings and after I transplanted into the garden. They did not really begin to fill in until July, when I gave them a boost of water-soluble fertilizer even in the garden beds. After that, they got quite bushy. That makes spacing a challenge if mass planted, as the garden bed looks sparse for 6 to 8 weeks. I hope switching to a low grower yet still spacing the plants close together in the border edges will solve this.

Plants in containers did better, likely because of the slow-release fertilizer.

Also, I recently read that the leaves can be made into a tea – I might try that next year (along with my chamomile).

Seed Starting Guide

Our last frost date is around May 13 according to the almanac however it’s rare for us not to have a cold snap before the May 24 weekend. So for 2026, this is my new schedule:

Start Date

• March 30 – April 5 (7–8 weeks before May 24)
• Do not start earlier — they resent sitting too long in pots.
• Germination temp: 21–24°C
• Days to germination: 7-14 (as my seeds are older, they will likely take longer this year than normal)

Sowing Method

• Sow directly in cell packs
• 2-3 seeds per cell
• Light helps, but not strictly required
• Cover ⅛–¼ inch

Growing On

• Thin to strongest seedling
• Temp: 18–22°C
• They like it warm, avoid colder sections of the greenhouse. If cool, move the the floor
• Gomphrena seedlings are very slow growers, have patience
• Light: 14–16 hours – high intensity so they stay compact until they have branched
• Pinch once when 3-6 inches tall
• Do not overwater — they prefer slightly dry conditions once established.
• Fertilize when 3 to 4 weeks old

Planting Out

• Frost tender
• Dislikes cold soil
• Wait until after May 24 or early June
• Soil temperature ideally 16°C
• Full maturity in the garden is long – 85 to 100 days