Eggplant
Solanum melongena
Also known asAubergine · Brinjal · Melongene · Garden egg · Berenjena
Environment
The bounded range this crop tolerates. Strict on light; outside the DLI band, yields drop sharply.
Climate and zones
- USDA zones
- 10–13 (winter low around -1°C)
- Frost
- frost sensitive (dies at first frost)
- Season
- warm (summer, frost-sensitive)
Growing systems
Root mass: heavy. Thin-channel systems can't hold this crop.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Perlite (Expanded volcanic glass) | neutral / inert | very low | low |
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | low |
| Soil-based mix (Potting soil) | varies | high | 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 | 1 |
| vegetative | 3 | 1 | 2 | 2.2 |
| flowering | 2 | 2 | 3 | 2.5 |
| fruiting | 1 | 2 | 4 | 2.8 |
Companion-growing notes
- Heavy uptake of potassium, calcium. 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
Not recommended
Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.
Care notes
A productive hydroponic crop similar in requirements to peppers and tomatoes. Dutch bucket, drip, or large DWC systems with staking. EC 2.0-3.5 mS/cm. pH 5.5-6.5. Temperature: 22–30°C (heat-loving; growth stalls below 18°C and frost kills the plant). Very high light (DLI 20-30 mol/m2/day). From transplant to first harvest: 65-80 days. The plants are medium to large (60–120 cm depending on variety) and benefit from staking or caging, especially when carrying multiple heavy fruits. Japanese and Chinese types are easier to manage in hydroponic systems than large Western types because the slender fruits are lighter and the plants are often more compact. Pollination: eggplant flowers are self-fertile but benefit from vibration to release pollen. Shake the plant gently or use an electric toothbrush on flower clusters. Harvest when the skin is glossy and the flesh gives slightly to pressure. Overripe eggplant has dull skin, brown seeds, and bitter flavor. Each plant produces 5-15 fruits over a season depending on variety. Flea beetles are the most common pest (they riddle the leaves with tiny holes); row cover or spinosad spray controls them.
Notable varieties
| Cultivar | Type | Days | Size | Notes |
|---|---|---|---|---|
| Black Beauty | heirloom | 80 | 600 g | Pre-1902 heirloom Italian-type. Large dark purple teardrop fruit, the supermarket default. Productive on bushy plants. Needs warm soil to set fruit; struggles in cool summers. |
| Ichiban | hybrid | 65 | 110 g | F1 Japanese-type. Long thin 20-25cm fruit, mild flesh with very few seeds. Earlier than Italian eggplants by 2 weeks; useful in zone 5-6 where the long season hurts Italian types. Continuous harvest from one plant for 8+ weeks. |
| Rosa Bianca | heirloom | 90 | 400 g | Italian heirloom with rose-purple skin streaked white. Mild creamy flesh, less bitter than dark eggplants, almost no salting needed. Longer season than Black Beauty; best in zones 7+. Beautiful enough to grow as ornamental. |
| Listada de Gandía | heirloom | 80 | 300 g | Spanish heirloom, purple and white striped 15-20cm fruit. Thin skin, mild flesh. Productive in hot dry climates; less reliable in cool maritime conditions. |
| Thai Long Green | open pollinated | 80 | 100 g | Pale green thin 25-30cm fruit for Thai curry and stir-fry. Tender flesh that needs no salting. Heat-tolerant; thrives in zone 9+ where Italian types stall. |