Fertilising guide

How to fertilise Joseph's Coat Amaranth (Amaranthus tricolor)— schedule & NPK

Also called Joseph's Coat, Chinese Spinach, Fountain Plant, Tampala.

More about joseph's coat amaranth

About Joseph's Coat Amaranth

Amaranthus tricolor · also called Joseph's Coat, Chinese Spinach · flowering

Joseph's Coat Amaranth is a dramatic, heat-loving annual grown primarily for its brilliantly coloured foliage in tricolour combinations of red, yellow, and green. A striking accent plant for tropical-themed beds. The ASPCA lists Amaranthus as toxic to pets, and the plants also accumulate nitrates which can be harmful to livestock if consumed in large quantities.

Growth habit: Upright, vigorous warm-season annual

Watch for — Caterpillars: Some moth caterpillars feed on Amaranthus foliage; pick off by hand or apply Bt (Bacillus thuringiensis) if severe.

What fertiliser joseph's coat amaranth actually wants — and why

Joseph's Coat Amaranth is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.

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 joseph's coat 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 joseph's coat 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 joseph's coat amaranth:

The dormant-season rule matters more than the exact interval: skip feeding entirely when joseph's coat 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 joseph's coat amaranth

Follow the flowering-feed label rate for joseph's coat amaranth, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.

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

Signs you are over-feeding joseph's coat amaranth

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

Lots of lush leaves but few flowers (too much nitrogen).
Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
Soft, sappy growth prone to aphids and mildew.

Signs you are under-feeding joseph's coat amaranth

Sparse, small, short-lived flowers and pale foliage.
A tired plant that stops blooming early in the season.
Weak growth and poor repeat-flowering after the first flush.

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

Flushing and leaching the salts

Container-grown joseph's coat amaranth accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.

Organic vs synthetic feeds for joseph's coat amaranth

Organic options

A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.

Synthetic / liquid feeds

A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.

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 joseph's coat amaranth — frequently asked questions

What fertiliser does joseph's coat amaranth need?

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Joseph's Coat Amaranth is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

How often should I feed joseph's coat amaranth?

Feed with a balanced liquid fertiliser every two to three weeks during the growing season. Avoid excess nitrogen which produces lush green growth at the expense of the vivid tricolour leaf display. A mid-season high-potash feed can intensify leaf colouring. Feed with a balanced liquid fertiliser every two to three weeks during the growing season. Avoid excess nitrogen which produces lush green growth at the expense of the vivid tricolour leaf display. A mid-season high-potash feed can intensify leaf colouring. For a hungry bloomer that means feeding regularly — sparingly through the growing season — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

What strength of feed for joseph's coat amaranth?

What does over-feeding joseph's coat amaranth look like?

Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on joseph's coat amaranth is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.

Should I flush the soil of joseph's coat amaranth?