Organic Gardening:

How to grow organic Aubergines

Aubergines do best in a greenhouse

Aubergines (Eggplant) Solanum melongena Family: Solanaceae (Group 8)

Aubergine, known in America as Eggplant, is a tropical bush up to 75cm (2½') tall with a spread of 60cm (2'), and with prickly leaves and stems. It is much more tender and difficult to grow than tomatoes and peppers (which are the same Family), probably because there hasn't been such a concerted effort to develop varieties that grow well in our cool climate. Still, with global warming hotting up, who knows what we'll be growing in a few years time?

Site/soil

Aubergines require deep, fertile soil. They grow best in a cold greenhouse, but can be moved outside in July and August in good summers if grown in large pots.

Cultivation

Sow in heat from mid-March to early April at 70-80ºF (21-30ºC). After germination, seedlings require a minimum nighttime temperature of 60ºF (16ºC) and daytime 64ºF (18ºC) to keep them growing. Pot on at 5cm (2") into 9cm (3½") pots, then into 13cm (5") pots if necessary.

Plant out in the greenhouse in late April to early May or outdoors under cloches after the last spring frost. Space 45cm (18") each way and provide staking.

Keep well watered. Pinch out at 15cm (6"). Restrict fruiting to one per stem, four per plant. Feed with tomato fertiliser every 10-12 days once fruits start to set.

Pests and Diseases

Glasshouse whitefly can be a problem in greenhouses. Growing repellent plants (see below) may discourage infestation. The best control is a parasitic insect called Encarsia formosa, but you have to stop them escaping by covering all potential exits with fine net (such as net curtain material). Early introduction, as soon as the pests are seen, is essential, but not before, or the parasite will die of starvation.

Red spider mite may infest crops both indoors and out. The problem is greatest where humidity is low, so raising the humidity is helpful. The predatory mite Phytoseiulus persimilis can be used indoors, introduced before infestation becomes too heavy (like Encarsia formosa above).

Aphids may appear on plants both indoors and out, colonising the undersides of the leaves. Grow repellent plants (see below) and spray with insecticidal soap or pyrethrum. Small infestations can be squashed with the fingers.
Basil, French Marigold and Shoofly plants are deterrents for both whitefly and aphids.