Heat and patience
Germination needs 24–28 °C (75–82 °F) and can take two to three weeks. If your room is cooler than that, start the seed somewhere warmer and move it once it has sprouted.
Reservoir at 20–24 °C (68–75 °F). Growth stops below 15 °C (59 °F) and fruit set fails below 18 °C (64 °F). This is not a crop for an unheated room in winter.
From sowing to first harvest expect 70–90 days. Aubergines are slower than tomatoes by a fortnight or so, and they do not forgive a late start.
Feeding and support
EC 1.8–2.2 through flowering and fruiting, pH 5.8–6.2. They are heavy feeders once fruit is set and heavy drinkers at the same time.
Stake from early — a single cane to 1 m (3.3 ft), tied loosely as the plant grows. Once fruit is developing, support individual trusses or the main stem will bend.
Remove the lower leaves that touch the lid, and pinch out the growing tip once the plant has set four or five fruit so it stops trying to make more and ripens what it has.
Pollination and fruit set
Aubergine flowers are self-pollinating but, like tomatoes, benefit from vibration. Tap the stem or the flower truss daily at midday while flowers are open.
Flowers that open and drop without setting fruit usually indicate temperature — too cold, or above 32 °C (90 °F). They can also drop from heavy nitrogen during flowering.
Harvesting
Harvest while the skin is glossy and a thumbnail pressed into it leaves a mark that springs back. A dull-skinned aubergine is over-ripe, and the flesh inside will be seedy and bitter.
Cut with a short section of stem attached. Regular harvesting keeps the plant producing; leaving fruit to mature stops new flowers setting.
Saving seed
Aubergines are self-pollinating but cross with other aubergine varieties through insects. Isolation of 30–50 metres (98–164 ft), or bag the flowers.
Leave a fruit on the plant well past eating ripeness until it is dull, hard and beginning to turn yellow. Then harvest it, cut it open, and scoop the seed from the flesh.
Ferment the seed in water for two days to remove the gel, rinse, and dry thoroughly. Viable for four to six years.