Fertilising guide

How to fertilise Globe amaranth (Gomphrena globosa)— schedule & NPK

Also called Globe amaranth, bachelor's button, makhmali.

More about globe amaranth

About Globe amaranth

Gomphrena globosa · also called Globe amaranth, bachelor's button · flowering

Globe amaranth is a heat-loving tropical annual producing clover-like, papery flowerheads in vibrant shades of magenta, purple, pink, white, and red from summer until frost. Native to Central America, it thrives in full sun and dry to moderately moist conditions. An exceptional cut and dried flower, it is widely grown in US gardens for its long bloom season.

Growth habit: Upright, freely branching annual with slightly hairy, oblong mid-green leaves. Globular, papery bracts (1–2 cm diameter) are produced continuously on long straight stems from summer to frost.

Watch for — Leaf spot (Cercospora): Circular brown spots with pale centres appear on older leaves in humid conditions. Remove affected foliage and improve spacing for airflow. Fungicide sprays are rarely necessary in home garden settings.

What fertiliser globe amaranth actually wants — and why

Globe amaranth flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for globe amaranth: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed globe amaranth, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For globe amaranth:

Light feeding with a balanced or low-nitrogen fertiliser (e.g., 5-10-5) at planting supports establishment. Avoid high nitrogen; it promotes leafy growth at the expense of flowers. One or two applications through summer is sufficient. In practice: no routine feeding at all for globe amaranth — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

The dormant-season rule matters more than the exact interval: skip feeding entirely when globe amaranth is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for globe amaranth

None is the correct answer for globe amaranth. The flower-versus-foliage trade-off is the whole point: hold back and you get the display.

Feeding always goes onto already-damp soil, never dry roots — water globe amaranth first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the globe amaranth watering schedule.

Signs you are over-feeding globe amaranth

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for globe amaranth:

Abundant leafy growth and very few flowers (the classic over-rich symptom).
Soft, floppy stems and a sprawling, leafy habit.
Scorched edges and salt crust if it has been fed in a container.

Signs you are under-feeding globe amaranth

Effectively never an issue — these plants flower on poverty.
Only on genuinely dead soil: weak, thin growth and few blooms.
A short-lived plant in completely spent container compost.

If the symptoms point at watering, light or roots rather than nutrition, the full globe amaranth care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

If globe amaranth has accidentally been fed and is all leaf, a plain-water flush plus a move to leaner soil resets it; otherwise no flushing is needed because you are not feeding it.

Organic vs synthetic feeds for globe amaranth

Organic options

A thin compost mulch for soil structure is the absolute most; mostly, give it nothing. UK/US: leave it lean — no manure, no liquid feed. Poor soil is the active ingredient here.

Synthetic / liquid feeds

None. Synthetic feeds, particularly anything with appreciable nitrogen, directly suppress flowering in globe amaranth.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising globe amaranth — frequently asked questions

What fertiliser does globe amaranth need?

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency. Globe amaranth flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

How often should I feed globe amaranth?

Light feeding with a balanced or low-nitrogen fertiliser (e.g., 5-10-5) at planting supports establishment. Avoid high nitrogen; it promotes leafy growth at the expense of flowers. One or two applications through summer is sufficient. Light feeding with a balanced or low-nitrogen fertiliser (e.g., 5-10-5) at planting supports establishment. Avoid high nitrogen; it promotes leafy growth at the expense of flowers. One or two applications through summer is sufficient. In practice: no routine feeding at all for globe amaranth — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

What strength of feed for globe amaranth?