This Allotment Pro editorial draft summarises the cited RHS guide. Check the source and adjust timings for local conditions.RHS source guide
Start early only when plants can remain in reliably warm, bright protected conditions.
Begin the main sowing period at a germination temperature of at least 21°C (70°F).
Sow later so tender plants do not outgrow their protected space before the last frost.
Move young plants into their final protected position.
Plant after hardening off so the change in temperature does not check growth.
Plant only after the last frost in a warm, sunny, sheltered position.
Cut ripe fruits when full-sized, glossy and well coloured; regular picking encourages further fruit development.
Protect or move plants under cover before nights turn cold if fruits are still ripening.
Aubergines, also called eggplants or brinjal, are tender, heat-loving members of the tomato and pepper family. They need a long warm season to flower and ripen fruit reliably in the UK, so an unheated or heated greenhouse gives the best chance of success. Outdoor crops are possible in very mild districts or during a long hot summer when plants receive full sun and shelter.
Plants may be raised from seed indoors or bought as young plants. They grow well in large containers, growing bags and fertile greenhouse borders, and newer compact, small-fruited cultivars are particularly useful where space or summer warmth is limited.
Aubergine cultivars vary widely in fruit colour, size and shape. Familiar deep-purple fruits sit alongside mauve, pink, white and green forms, while the fruit may be round, egg-shaped, oval, long or slender. Small-fruited and compact cultivars generally fit containers more easily and can be a practical choice for shorter growing seasons.
Seed gives the widest choice and should be bought in time for late-winter or early-spring sowing. Plug plants and young plants reduce the amount of heated indoor space required, although fewer cultivars may be available. Grafted plants cost more but are usually more vigorous and robust, which may help crops growing in cooler outdoor conditions.
An early-cropping aubergine suited to an unheated glasshouse, producing large, glossy, very dark purple fruits.
An early cultivar carrying medium-sized, oval white fruits that may be slightly ribbed and have white flesh.
A compact choice for containers, with highly glossy purple fruits shaped like large eggs.
A compact, thornless cultivar bred for containers, producing a heavy crop of small, fast-maturing, egg-shaped dark-purple fruits.
Sow indoors from February for most crops. January sowing is useful only for plants destined for a heated greenhouse or warm conservatory, while plants intended to fruit outdoors are best delayed until early March. Aubergines need at least 21°C (70°F) to germinate, so use a heated propagator or another consistently warm indoor position.
Move newly emerged seedlings promptly into bright conditions. Keep young plants at 16–18°C (60–64°F), water as needed and avoid letting the compost become saturated. Once the first true leaves have formed, move each seedling into its own 7.5cm (3in) pot or individual module with minimal root disturbance.
Continue growing plants in warmth and good light. Pot on before roots become congested, and do not move these frost-tender plants into an unheated or outdoor position too early.
Plant into a heated greenhouse in April, an unheated greenhouse in early May, or outdoors in late May or early June after the final frost. Harden plants off before they enter an unheated greenhouse or outdoor position. Set each plant at the same depth as it grew in its pot and insert a support cane at planting time.
Choose a container at least 30cm (1ft) in diameter, fill it with peat-free multipurpose compost and place one aubergine in the centre. A standard growing bag can hold two plants. Outdoor containers need the warmest sheltered position available, such as a sunny wall or south-facing patio.
Warm outdoor soil under cloches for two weeks before transplanting. Enrich the site with garden compost or well-rotted manure, or plant through an established organic mulch in a no-dig bed. Space plants 60cm (2ft) apart. Newly planted outdoor aubergines benefit from cloches or plastic-free fleece for their first couple of weeks.
Aubergines need steady warmth and moisture throughout flowering and fruit development. Some plants carry small stem spines, so handle them carefully when tying, watering and harvesting.
Water regularly so the root zone remains consistently moist without becoming waterlogged. Containers dry especially quickly and may need daily watering in hot weather. In protected cultivation, mist foliage with tepid water up to twice daily or damp down the greenhouse floor in the morning during hot weather. The resulting humidity helps fruiting and makes conditions less favourable for glasshouse red spider mites.
After planting, spread a generous organic mulch such as garden compost or well-rotted manure around plants in soil or greenhouse borders. This conserves moisture and reduces weed growth. Once the first flowers appear, feed container plants every two weeks with an organic high-potassium liquid fertiliser. Plants in enriched open ground may crop without regular feeding, although supplementary feed can improve yield.
When plants reach about 30cm (1ft), pinch out the main growing tip to encourage a bushier framework with more fruiting side-shoots. Tie the main stem to a sturdy bamboo cane and add further support if side-shoots become heavy with fruit.
Open greenhouse and coldframe doors and vents on warm flowering days so pollinating insects can reach the plants. Misting flowers can help pollen move, or flowers can be pollinated gently with a small paintbrush. On large-fruited cultivars, remove later flowers once five or six fruits have set so the established crop can develop. Small-fruited cultivars can carry more.
Remove fruits that begin forming after late summer because they are unlikely to ripen. Protect outdoor plants if fruit remains unripe by late September, and bring movable pots under cover before overnight temperatures fall.
Harvest usually begins in August. Cut each fruit with a short length of stalk when it has reached the expected size and colour and the skin is still glossy. A dull surface usually indicates an over-ripe fruit that may have developed bitterness.
Use secateurs or a sharp knife rather than pulling, especially on spiny plants. Pick regularly as fruits ripen to direct the plant's energy into the remaining crop and encourage later fruits to develop.
Poor fruiting is commonly linked to insufficient heat, sunlight or season length. Aubergines need at least five months from sowing to harvest and a reliable water supply through summer. Give outdoor plants the hottest sheltered site available and avoid checks in growth caused by cold planting conditions or dry compost.
Aphids cluster on tender growth and leaf undersides, reducing plant vigour and distorting young leaves. Inspect plants regularly so colonies are noticed while small.
Problem sourceThese sap-feeding mites thrive in hot, dry protected conditions. Their feeding causes pale mottling and can lead to early leaf loss; maintaining appropriate greenhouse humidity and checking leaf undersides helps early detection.
Problem sourceWhiteflies feed on sap and excrete sticky honeydew, particularly on greenhouse crops. Look beneath leaves for adults and immature stages before populations build.
Problem source
