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Iron Cross Plant Care

Oxalis tetraphylla · Oxalidaceae

⚠️ Toxic to pets 🎯 Easy ☀️ Bright indirect 💧 Every 7–10 days

🕮 8 min read 🕓 Last reviewed: 2026-08-23

Care at a glance

Watering

Every 7–10 days

Light

Bright indirect

Temperature

15–25 °C (59–77 °F)

Humidity

Average

Soil

standard well-draining potting mix

Difficulty

Easy

Mature size

15–30 cm (6–12 in)

Pet safety

Toxic to pets

Care effort Medium

The short version

Beginner-friendly and forgiving.
Give it Bright indirect.
Water every 7–10 days.
Keep away from cats and dogs.

The Iron Cross Plant (Oxalis tetraphylla) is a popular houseplant from the Oxalidaceae family, native to Mexico. It is rated Easy to grow and typically reaches 15–30 cm indoors. Here is everything you need to keep it healthy — watering, light, humidity, feeding, propagation, and pet safety. It is a Moderate grower, putting on most of its growth in the warm, bright months of spring and summer.

Also known asOxalis tetraphyllaオキザリス・デッペイ铁十字酢浆草Glücksklee

📋Quick facts

Growth rate	Moderate
Mature size	15–30 cm (6–12 in)
Native region	Mexico
Plant family	Oxalidaceae
Toxicity	Toxic
Air-purifying	No
Ideal for	beginners, a pop of colour

⚖️Pros & cons

Pros

Hard to kill; great for beginners
Flowers indoors
Compact — fits a desk or shelf

Cons

Toxic to cats and dogs

💧Watering

Water your Iron Cross Plant roughly every 7–10 days, letting the top few centimetres of soil dry out between waterings. Always empty the saucer so the roots never sit in water — overwatering is the most common way this plant is lost.

Not sure when to water? Push a finger 2–3 cm into the soil and water only when it feels dry at that depth — a cheap moisture meter or the weight of the pot works too. Water thoroughly until it runs from the drainage holes, then tip away anything left in the saucer. Soft, yellowing lower leaves usually mean too much water; crispy, curling leaves usually mean too little. Always ease off in the darker months, when the plant drinks far less.

Never forget to water

Adds a repeating event to Google Calendar every 9 days.

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☀️Light & placement

The Iron Cross Plant likes bright, indirect light — near a window but out of direct midday sun, which can scorch the leaves.

Set it right beside an east window, or just back from a south/west one behind a sheer curtain, so it gets plenty of light without direct midday rays on the leaves. Rotate the pot weekly for even growth, and dust the leaves so they can drink in the light.

🌡️Temperature & humidity

Keep it between 15–25 °C and away from cold draughts and heating vents. It prefers Average humidity; if your air is dry, group it with other plants or use a humidifier.

🪴Soil & feeding

Plant it in standard well-draining potting mix. Feed with a diluted balanced feed monthly in spring and summer, and stop feeding in autumn and winter when growth slows.

🗓️Season-by-season care

Season	Watering	What to do
Spring (Mar–May)	Resume regular watering as growth restarts.	The main growing season begins — start feeding again, repot if it is pot-bound, and take cuttings now for the best success.
Summer (Jun–Aug)	This is the thirstiest season; check the soil more often.	Keep feeding on schedule, watch for pests in the warmth, and shield the leaves from scorching midday glass. Higher humidity is welcome.
Autumn (Sep–Nov)	Let the soil dry a little longer between waterings.	Taper off feeding as growth slows, and move the plant away from cold windows and doorways before the first chills.
Winter (Dec–Feb)	Water sparingly — overwatering now is the number-one killer.	Stop feeding, give it the brightest spot you have, and keep it away from radiators, heat vents, and cold draughts.

🪟Repotting

Repot roughly every 2 years, ideally in spring as growth picks up. Move up just one pot size (2–3 cm wider) with drainage holes — too big a pot holds water and invites root rot. Signs it is time: roots creeping from the drainage holes or circling the surface, water running straight through, or growth that has stalled. In the years you do not repot, scrape off and replace the top few centimetres of soil.

✂️How to propagate, step by step

Spring and early summer, during active growth, give the best success. Here is how to do it, step by step:

division at repotting

Water the plant the day before to reduce stress on the roots.
Slide it out of its pot and gently shake off the loose soil.
Tease the root ball into sections, each with healthy roots and a few shoots.
Pot each section into fresh mix at its original depth.
Water them in and keep out of direct sun for a week while they recover.

offsets (pups)

Wait until the offset (pup) is about a third the size of the parent.
Unpot the plant so you can see where the pup joins it.
Separate the pup, keeping as many of its own roots as you can.
Let any succulent cuts callus for a day; pot rooted pups straight away.
Plant in suitable mix and water lightly until it establishes.

🔬Classification

Plant type	Flowering plant
Genus	Oxalis
Family	Oxalidaceae · Oxalidaceae
Native to	Mexico

🩺Common problems

Symptom	Likely cause	What to do
Yellowing leaves	Usually overwatering or poor drainage	Let the soil dry more between waterings and make sure the pot drains.
Drooping or wilting	Too little (or too much) water	Check the soil: water if dry, ease off if soggy.
Soft, mushy base (root rot)	Waterlogged soil	Repot into fresh dry mix, trim rotten roots, and water less.
Will not flower	Too little light, or it is not mature yet	Give it brighter light and be patient through a season.

🩺 Plant Doctor →

🐛Pests & prevention

The usual indoor pests are spider mites (fine webbing, speckled leaves), mealybugs (white cotton-wool tufts), scale (small brown bumps), and fungus gnats (tiny flies from soggy soil). Inspect any new plant before it joins the others, wipe the leaves now and then, and let the topsoil dry to keep gnats away. At the first sign, isolate the plant, wipe or rinse off what you can, and treat with insecticidal soap or neem oil every week until it is clear.

🐾Is it safe for pets?

The Iron Cross Plant is toxic to cats and dogs (soluble calcium oxalates). Keep it out of reach of pets and children. If you think an animal has chewed it, contact your vet or a pet poison line. If a curious cat or dog chews it, soluble oxalates can, in larger amounts, bind calcium and affect the kidneys — so ingestion should be taken seriously. It is rarely life-threatening in small amounts, but rinse the animal’s mouth, take away any plant pieces, and call your vet if symptoms are severe or last more than a short while.

Toxicity information is a general guide based on ASPCA data. If your pet or child may have eaten any part of a plant, contact a vet or poison control right away.