Fertilising guide

How to fertilise New Zealand Spinach (Tetragonia tetragonioides)— schedule & NPK

Also called New Zealand spinach, sea spinach, warrigal greens.

More about new zealand spinach

About New Zealand Spinach

Tetragonia tetragonioides · also called New Zealand spinach, sea spinach · edible

New Zealand spinach is a sprawling, heat-loving leafy green from the fig-marigold family, unrelated to true spinach. It thrives through hot summers without bolting, producing a steady flush of thick, triangular, succulent-textured leaves where ordinary spinach fails. Pick the tender shoot tips regularly; always blanch the leaves before eating to drive off the high oxalates.

Growth habit: Low, vigorously spreading and trailing branched stems forming a dense ground-covering mat of thick triangular leaves; a tender perennial grown as an annual in temperate gardens.

What fertiliser new zealand spinach actually wants — and why

New Zealand Spinach is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.

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 new zealand spinach: 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 new zealand spinach, 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 new zealand spinach:

Not a heavy feeder. A compost-enriched bed plus an occasional balanced or seaweed liquid feed every 4-6 weeks is plenty; too much nitrogen produces lush leaves but can raise nitrate and oxalate levels. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).

The dormant-season rule matters more than the exact interval: skip feeding entirely when new zealand spinach 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 new zealand spinach

Use the vegetable-feed label rate for new zealand spinach. Steady availability matters more than a strong dose — a check in growth makes leaves tough and can trigger bolting.

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

Signs you are over-feeding new zealand spinach

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

Very soft, floppy, dark-green growth that attracts aphids.
Excess leafy growth at the expense of hearts/heads in cabbage and the like.
Salt crust and scorched leaf edges in containers; nitrate-heavy leaves.

Signs you are under-feeding new zealand spinach

Pale, yellow-green leaves, oldest first, and slow growth.
Small, tough, bitter leaves and premature bolting.
Weak, stunted heads in cabbage, broccoli and cauliflower.

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

Flushing and leaching the salts

For container-grown new zealand spinach, water until it drains freely each time and flush pots monthly with plain water to stop nitrogen salts accumulating; in the ground, good compost levels naturally buffer this.

Organic vs synthetic feeds for new zealand spinach

Organic options

Well-rotted manure or compost dug in, plus nitrogen-rich liquid feeds like diluted chicken-manure pellets or nettle feed. UK: pelleted chicken manure or Westland; US: Espoma Garden-tone or blood meal. Steady and soil-building.

Synthetic / liquid feeds

A balanced feed at planting then a high-nitrogen liquid or granular side-dress — UK: Growmore then a nitrogen feed or Phostrogen; US: a 10-10-10 then a high-N (e.g. 21-0-0) side-dress or Miracle-Gro.

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 new zealand spinach — frequently asked questions

What fertiliser does new zealand spinach need?

A nitrogen-leaning feed (higher first number) or compost-rich soil — nitrogen drives the fast, tender leafy growth this crop is grown for. Phosphorus and potassium matter far less here than for fruiting crops. New Zealand Spinach is grown entirely for its leaves, so nitrogen is the priority — steady, nitrogen-leaning feeding keeps it growing fast, tender and unbolted.

How often should I feed new zealand spinach?

Not a heavy feeder. A compost-enriched bed plus an occasional balanced or seaweed liquid feed every 4-6 weeks is plenty; too much nitrogen produces lush leaves but can raise nitrate and oxalate levels. Not a heavy feeder. A compost-enriched bed plus an occasional balanced or seaweed liquid feed every 4-6 weeks is plenty; too much nitrogen produces lush leaves but can raise nitrate and oxalate levels. In practice: a balanced or compost-rich start, then a nitrogen side-dress or liquid feed every 3-4 weeks through the cropping period in the main season (spring through early autumn).

What strength of feed for new zealand spinach?