Strict Hygrophila (Temple Plant) care

Light

Bright but filtered. Strict Hygrophila burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Requires moderate to high aquarium lighting of at least 2-3 watts per gallon (PAR 30-80+). Under low light it becomes leggy and pale; good light produces dense, compact growth with vivid green foliage. If you only have a south window, set the plant back 1.5 m or hang a sheer curtain — both knock the intensity down into the right range.

Watering

Watering strict hygrophila: fully submerged aquatic plant; keep in aquarium water at all times. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Thrives in slightly soft to moderately hard freshwater, pH 6.5-7.5, temperature 22-28°C. Regular water changes of 25-30% weekly maintain nutrient levels. Benefits from CO2 supplementation but will grow without it.

Soil and pot

Strict Hygrophila grows best in nutrient-rich aquatic substrate. Plant into fine-grade aquarium gravel or a dedicated planted-tank substrate (e.g., ADA Aqua Soil or Seachem Flourite) at least 5 cm deep. Roots aggressively; a root-tab fertiliser near the base accelerates growth. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Strict Hygrophila sits happiest at around 100% (fully aquatic) humidity and 22-28°C (72-82°F). As a submerged aquatic, it is permanently immersed. Emersed cultivation is possible on moist soil in a humid terrarium or paludarium at 70-90% ambient humidity. If you keep the room above 22 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed strict hygrophila sparingly. Dose a balanced liquid aquarium fertiliser (e.g., Seachem Flourish) weekly following label rates. Iron-rich supplements promote deep-green colouration; avoid excess phosphate which encourages algae competition. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on strict hygrophila in the Growli community. Each is annotated with the most common cause so you know where to start.

• Yellowing leaves — Usually indicates iron or micronutrient deficiency; dose an iron-rich liquid fertiliser and check substrate nutrition.
• Leggy, sparse growth — Caused by insufficient light; increase photoperiod to 10-12 hours or upgrade to higher-output LEDs.
• Algae on leaves — Excess nutrients combined with low plant density; increase planting density, reduce photoperiod slightly, and add fast-growing competitors.
• Stem rot at substrate — Poor substrate circulation or compaction; gently loosen substrate around roots and ensure adequate water flow.
• Slow growth without CO2 — Inject CO2 at 20-30 ppm or add liquid carbon supplement (glutaraldehyde-based) to unlock faster, denser growth.

Companion plants

Strict Hygrophila pairs well with Vallisneria spiralis, Rotala rotundifolia, and Cryptocoryne wendtii. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Propagate by stem cuttings: trim healthy tops 8-12 cm long, remove lower leaves, and plant directly into substrate. New roots emerge within 1-2 weeks. Side shoots that appear on mature stems can also be cut and replanted. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Strict Hygrophila is pet-safe. Hygrophila stricta is not listed on the ASPCA Toxic Plants database, and the genus Hygrophila contains no known mammalian toxins. It is widely kept in aquaria with fish, amphibians, and aquatic turtles without reported issues. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Strict Hygrophila deep-dive guides

Every aspect of strict hygrophila care, each with its own calibrated guide:

• Common strict hygrophila problems & fixes
• Strict Hygrophila watering schedule
• Strict Hygrophila light requirements
• Best soil mix for strict hygrophila
• Strict Hygrophila fertilizing guide
• When to repot strict hygrophila
• How to propagate strict hygrophila
• How to prune strict hygrophila
• What's eating my strict hygrophila?
• Strict Hygrophila growth rate & size
• Strict Hygrophila cold hardiness
• Strict Hygrophila temperature & humidity
• Is strict hygrophila toxic to cats & dogs?
• Is strict hygrophila toxic to cats?
• Is strict hygrophila toxic to dogs?
• All 6 Hygrophila varieties

Featured in these plant shortlists

Strict Hygrophila qualifies for 6 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
• Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
• Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
• Best fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
• Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
• Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
• Browse all 30 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Strict Hygrophila is also known as Temple Plant, Indian Waterweed, and Stricta.

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