Seagrass Plant Care
Halophila capricorni Larkum
Updated · Sources · How we source care data
Halophila capricorni, also known as Capricorn seagrass, is a unique underwater plant with delicate ribbon-like leaves that are bright green in color. It is popular among marine enthusiasts for its ability to create a lush and vibrant underwater habitat.
Every 7–14 days
Full sun to partial shade
70–85°F
80–90%
At a glance
How do you care for Seagrass?
Water Seagrass every 7–14 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 70–85°F (21–29°C) and 80–90% humidity.
What Is the Seagrass?
Seagrass (Halophila capricorni) belongs to the Hydrocharitaceae family within the Halophila genus. Seagrass is native to Australia.
Seagrass displays a spreading aquatic perennial growth habit, reaching up to tall with a spread of approximately . Seagrass produces small inconspicuous flowers underwater.
Leaf size: approximately 12 inches.
How Often Should You Water a Seagrass?
Halophila capricorni requires watering every 7–14 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 7–14 days
Let soil partially dry between waterings
What Light Does the Seagrass Need?
Seagrass thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Seagrass Prefer?
Halophila capricorni grows best at temperatures of 70–85°F. Seagrass prefers humidity levels of 80–90%. A pebble tray or humidifier helps maintain adequate moisture around the plant.
Temperature
70–85°F
Humidity
80–90%
What Soil Mix Works Best for a Seagrass?
Sandy, well-draining aquatic substrate with high organic content. Good drainage is essential for Seagrass to prevent waterlogging, which leads to root rot and fungal issues.
How Do You Repot a Seagrass?
Repot every 1-2 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Seagrass?
Seagrass can be propagated through vegetative propagation, division, rhizome cuttings. Similar propagation techniques also apply to heart-shaped seagrass plant care, which shares the same genus.
Is the Seagrass Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Seagrass, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Seagrass?
Seagrass is susceptible to algae, aquatic weeds. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
Keep exploring plants
Seagrass is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Halophila genus — compare its care with other Halophila species on PlantoScan.
Halophila is part of the Hydrocharitaceae plant family — browse all Hydrocharitaceae genera and species.
Seagrass thrives in bright light and direct sun — see other bright-light plants.
More Halophila Species
Other Halophila species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Halophila capricorni Larkum, family Hydrocharitaceae (first published in Aquatic Bot. 51: 320 (1995)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Seagrass, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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