Greater Duckweed
spirodela polyrhiza
Also known as: ["Common Duckweed","Water Lentil"]
Overview
A small, free-floating aquatic plant with simple oval leaves and fine rootlets, often found in still or slow-moving freshwater habitats.
Benefits & Perks
["fast growing","wildlife attractant (bees, butterflies, birds)","disease resistant"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Liliopsida |
| Order: | Alismatales |
| Family: | Araceae |
| Genus: | Spirodela |
| Botanical Name: | Spirodela polyrhiza |
Plant Characteristics
Basic Information
- Category: Herbs & Weeds
- Suitable Location: still or slow-moving freshwater ponds, lakes, or garden water features
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"10–30°C"}
- Hardiness: {"zones":"6–10"}
- Misting: not required
- Drainage: Moderate drainage; prefers consistently moist but not waterlogged soil.
- Soil Type: Rich, loamy soil with good organic matter; can also thrive in water gardens or aquatic setups.
Maintenance Level
- Maintenance Level: very low
- Toughness Level: very high
- Pruning Frequency: As needed, typically every few months or when dead foliage accumulates.
- Pruning Intensity: Light pruning; focus on removing only damaged or decaying parts.
Care Details
Ideal Sunlight Coverage:
Bright indirect light for 4–6 hours daily; tolerates partial shade but may grow slower.
Sunlight Tolerance Tips:
Acclimate gradually to intense light to avoid scorching; place in filtered light outdoors or near an east-facing window indoors; avoid direct midday sun.
Care Requirements
Care Difficulty
very easyeasy
Sunlight
full sun to partial shade
Rotate plant weekly for even growth; use sheer curtains to diffuse strong light; adjust light exposure seasonally.
Watering
daily in extreme heat, otherwise as needed to maintain water level
Keep soil perpetually moist; avoid waterlogging by ensuring proper drainage; water in the morning to reduce evaporation.
Soil
not required, grows in water
pH: Slightly acidic to neutral (pH 6.0–7.0).
Keep soil consistently moist; avoid compacted soil; enrich with organic matter annually.
Temperature
Prefers 60–75°F (15–24°C); tolerates cooler temperatures but growth slows below 50°F (10°C).
Monitor temperature fluctuations; protect from drafts; adjust watering based on temperature.
Fertilizing
rarely required, monthly if in a contained water system
Fertilize only when actively growing; avoid over-fertilizing to prevent nutrient burn; flush soil occasionally to prevent salt buildup.
Propagation
Methods
Division of rhizomes or runners; easily propagated by separating small plants from the main cluster.
Step-by-Step Propagation Guide
- Separate small plants from the main cluster.
- Place in water or moist soil.
- Maintain humidity and warmth.
Best Time: Spring or early summer when the plant is actively growing.
Environment
Warm, humid environment with indirect light; keep consistently moist.
Medium
Water or moist soil; can also be propagated in floating water cultures.
Hormone
Not required; natural rooting is efficient.
Timeline
New plants establish within 1–2 weeks in favorable conditions.
Tools Needed
Small scissors, tweezers, containers for water or soil.
Quick Tips
Ensure each division has roots; maintain stable conditions; avoid disturbing new roots.
Pruning & Repotting
Pruning Guide
Method
Snip off dead leaves at the base with clean scissors; avoid cutting healthy growth.
Pruning Plan
Minimal pruning needed; remove dead or yellowing leaves to maintain appearance and health.
Tools
Clean scissors or small pruning shears.
Checklist
Check for dead or yellowing leaves; use clean tools; avoid over-pruning.
Repotting Guide
Best Season
Spring, when the plant is entering its active growth phase.
Pot Size
Choose a pot one size larger than the current one; ensure it has drainage holes.
Method
Gently remove the plant; trim any dead roots; place in fresh soil with good drainage; water lightly after repotting.
Suggestions
Repot only when the plant outgrows its container or soil becomes depleted; typically every 1–2 years.
Checklist
Check root bound status; prepare new soil mix; handle roots carefully; water after repotting.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture daily; water thoroughly but infrequently; ensure proper drainage; adjust for seasonal changes.
How to Apply Water Properly
Apply water gently to the soil surface until evenly moist; ensure water reaches the root zone without pooling; allow excess to drain away to prevent root rot.
Watering Schedule Tips
Water daily to maintain consistently moist soil; adjust frequency based on temperature and humidity to prevent drying out.
Soil Improvement
Add compost or peat moss to enhance fertility and moisture retention; ensure good aeration with perlite or sand if needed.
Temperature Stress Management
Signs of Temperature Issues
Wilting, yellowing leaves, or stunted growth in extreme heat or cold; leaf drop in prolonged cold stress.
Cold Stress
Growth slows or halts; leaves may turn yellow or brown; risk of root damage in freezing temperatures.
Solution: Move to a warmer location; insulate pots; avoid watering excessively during cold periods.
Hot Stress
Leaves may wilt, scorch, or dry out; growth may become leggy or weak.
Solution: Provide shade during peak heat; increase humidity; water more frequently but avoid waterlogging.
Fertilizing Guide
Fertilizing Checklist
Check growth phase before fertilizing; dilute fertilizer correctly; water before applying fertilizer.
Fertilizing Method
Use a balanced liquid fertilizer diluted to half strength every 4–6 weeks during active growth; reduce or stop in winter.
Common Problems & Solutions
Toxicity Warning
Cats
Non-toxicSpirodela polyrhiza is not considered toxic to cats. It poses no significant risk if ingested or if contact occurs.
⚡ Toxic If:
Generally non-toxic
Dogs
Non-toxicSpirodela polyrhiza is not considered toxic to dogs. It is commonly found in ponds and water gardens where dogs may come into contact with it.
⚡ Toxic If:
Generally non-toxic
Humans
Non-toxicSpirodela polyrhiza, commonly known as common duckweed, is not considered toxic to humans under normal circumstances. It is often used in aquatic systems for water purification and as a food source for certain animals.
⚡ Toxic If:
Generally non-toxic
Frequently Asked Questions
Q: Is Spirodela polyrhiza edible?
A: Yes, it is edible and is sometimes cultivated for its nutritional value, particularly in Asia.
Q: How does Spirodela polyrhiza reproduce?
A: It reproduces asexually through vegetative budding, where new plants grow from the parent plant.
Q: Can Spirodela polyrhiza help purify water?
A: Yes, it can absorb excess nutrients from water, helping to reduce algal blooms and improve water quality.
Quick Reference
| Family: | Araceae |
| Care: | very easy |
| Light: | full sun to partial shade |
| Water: | daily in extreme heat, otherwi |
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