Can you grow New Zealand spinach hydroponically? Yes. New Zealand spinach (Tetragonia tetragonioides) is a heat-tolerant, salt-tolerant green that adapted well to ebb-and-flow hydroponics in a 2025 University of Palermo trial. Soak the hard seed capsules for 24 hours, expect slow, uneven sprouting, feed a full-strength solution, and harvest tender tips again and again through summer.
Key takeaway: New Zealand spinach thrives in heat; soak seed 24 hours, feed full strength, and pinch tips often.
| Step | What to do | Source |
|---|---|---|
| 1. Soak | Soak seed capsules in water for 24 hours | USU |
| 2. Sow | Plant ½ inch (1.3 cm) deep; keep moist | USU |
| 3. Wait | Allow up to 2 or 3 weeks for emergence | USU |
| 4. Feed | Full-strength solution; water-only plants were stunted | Univ. of Palermo |
| 5. Space | 12 to 18 inches (30 to 46 cm) for mature plants | UH CTAHR |
| 6. Harvest | Pinch the top 2 to 3 inches (5 to 8 cm) of shoots | UH CTAHR |
What Is New Zealand Spinach?
A heat-loving spinach substitute. University of Hawaii CTAHR describes Tetragonia tetragonioides as a branched, herbaceous plant 1 to 2 feet (30 to 60 cm) tall with a mild, spinach-like flavor. It is not true spinach. Utah State University Extension notes it is also called Warrigal greens and grows in hot, dry months when regular spinach bolts.
How Do You Germinate New Zealand Spinach Seeds?
Soak first, then be patient. USU says soaking seeds in water for 24 hours hastens germination, yet seedlings may take 2 or 3 weeks and emerge unevenly. Each “seed” is really a hard capsule holding several seeds; the Palermo team notes 4 to 6 per capsule. Sow ½ inch (1.3 cm) deep and keep the medium moist.
Warmth helps: the Palermo trays sat in a dark room at 77°F (25°C) and emerged in about 7 days. See our seedling heat mats and humidity domes guide.
Does New Zealand Spinach Grow Well in Hydroponics?
Yes, according to research. Esposito and colleagues at the University of Palermo grew it in an ebb-and-flow system and found it “adapted well to hydroponic cultivation” in both autumn-winter and spring. Baby plants were ready 53 days after sowing in winter and 31 days in spring, when warmer weather and longer days sped growth.
New to flood tables? Read our ebb and flow hydroponics guide.
What Nutrient Strength Does New Zealand Spinach Need?
Full strength worked best. In the Palermo trial, plants given only water were stunted and yellow, half strength improved them, and full strength gave the highest yield. That solution held about 215 mg/L nitrogen at an EC near 2.5 mS/cm. The authors note this salt-tolerant species tolerates far higher salinity than lettuce or arugula.
Check readings with our guide to temperature effects on nutrient uptake and EC.
How Much Heat Can New Zealand Spinach Take?
Plenty. USU calls it heat and drought tolerant and says it keeps producing in warm summer and fall months when regular spinach goes to seed and turns bitter. UH CTAHR notes it can be grown year-round at low elevations in Hawaii. That makes it a strong swap for spinach bolting in hydroponics.
How Do You Harvest New Zealand Spinach?
Pinch the tips often. UH CTAHR says to harvest the top 2 to 3 inches (5 to 8 cm) of shoots once plants reach 1 to 2 feet (30 to 60 cm); new growth forms at the nodes below the cut. USU adds that regular trimming keeps growth lush, and generous feeding prevents early flowering, which stops leaf production.
- Cut just above a leaf node.
- Take only young leaves and tips.
- Keep feeding so plants do not flower early.
For planning, USU suggests 2 or 3 plants per person for fresh eating, and notes the spreading habit fills space quickly.
Is New Zealand Spinach Safe to Eat Raw?
Yes, in moderation. USU warns the leaves have a high oxalate content and suggests blanching for 3 minutes, discarding the water and chilling in ice water, though many people eat it raw in salads. The Palermo study found full-strength feeding lowered oxalic acid by about 11.5 percent compared with water only.
How Long Does New Zealand Spinach Keep?
Up to about two weeks or more. USU says to store leaves at 35°F (2°C) and 95 to 100 percent humidity for 2 to 3 weeks. Palermo researchers found packaged baby plants kept good quality for at least 14 days at 39°F (4°C). Seed stays viable up to 5 years, per USU.
FAQ About New Zealand Spinach
Is New Zealand spinach a true spinach?
No. It is Tetragonia tetragonioides, a different plant with a spinach-like taste.
Why are my seeds not sprouting?
They are slow. Soak 24 hours and allow up to 3 weeks.
Does it bolt in heat?
It tolerates heat far better than spinach; keep feeding to delay flowering.
What EC should I use?
A Palermo trial got the best yield near 2.5 mS/cm.
Do pests bother it?
USU reports very good insect and disease resistance.
Sources
- Utah State University Extension, Samuelson and Drost — New Zealand Spinach in the Garden
- University of Hawaii CTAHR, Valenzuela and Riede — New Zealand Spinach (PDF)
- Esposito et al., University of Palermo, Horticulturae 2025 — Hydroponic Cultivation of Tetragonia tetragonioides
- Photo credits (Wikimedia Commons, edited with titles): Starr-090702-2186-Tetragonia tetragonioides-flowers and leaves-Keanae-Maui (24600548479) by Forest and Kim Starr (CC BY 3.0 us); Tetragonia tetragonioides kz05 by Krzysztof Ziarnek, Kenraiz (CC BY-SA 4.0); Tetragonia tetragonioides kz10 by Krzysztof Ziarnek, Kenraiz (CC BY 4.0); Bulakeña vegetable market vendor watering vegetable seedling for sale 07 by FBenjr123 (CC BY-SA 4.0)