Lotus
Nelumbo nucifera
Also known asSacred lotus · Indian lotus · Bean of India · Hasu (Japanese) · Renkon (lotus root) · Nelumbo
Environment
The bounded range this crop tolerates. Strict on light; outside the DLI band, yields drop sharply.
Climate and zones
- USDA zones
- 5–11 (winter low around -29°C)
- Frost
- very hardy (survives deep cold)
- Season
- warm (summer, frost-sensitive)
Growing systems
Root mass: very heavy. Thin-channel systems can't hold this crop.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
Nutrient demand by stage
NPK ratios are relative weights. EC targets shift through the plant's life.
| Stage | N | P | K | EC (mS/cm) |
|---|---|---|---|---|
| seedling | 1 | 1 | 1 | 0.8 |
| vegetative | 2 | 1 | 3 | 2 |
Companion-growing notes
- Heavy uptake of potassium. Co-grown crops with the same demand will end up deficient even at "correct" EC.
- High transpiration. Regular reservoir top-ups needed during fruiting.
Aquaponics suitability
Compatible
Fish waste provides enough nitrogen for healthy growth. Supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
A unique aquaponics crop grown directly in the fish system water or in large containers connected to the system. Requires a large, shallow container (60 L, 30 cm wide, 20–30 cm deep) filled with heavy, clay-based aquatic planting media to anchor the rhizome. The container is submerged or partially submerged with 10–20 cm of water above the media surface. Temperature: 22–32°C (tropical; the rhizome survives winter dormancy in zones 5+ if the water doesn't freeze solid, but active growth requires warmth). Full sun (DLI 18-30 mol/m2/day; lotus needs very strong light for flowering and rhizome development). Plant tubers horizontally in early spring, barely covered by media. Growth emerges as floating pads, then aerial leaves, then flowers. Harvest rhizome sections in autumn after the leaves die back, or in early spring before growth resumes. Each plant produces 1–3 kg of rhizome annually once established. For aquaponics, lotus is one of the few crops that can grow directly in the fish tank water, making it a natural integration with tilapia or koi systems.
Legality
| Jurisdiction | Status | Notes |
|---|---|---|
| Connecticut | restricted | Connecticut Invasive Plants Council watch list; sale restricted verified 2026-05-13 |
| Victoria | check local regulations | Restricted in some Victorian waterways as a potential invasive verified 2026-05-13 |