In my greenhouse this month, the aubergines have finally stopped sulking. For weeks after planting out they sat there looking faintly offended by the whole business, and then, almost overnight, the way these things do, they put on a growth spurt, their leaves gone glossy and purple-veined, the first flowers unfurling like small, star-shaped promises, and then the very first tiny fruits. If you’ve grown aubergines before, you’ll know that sulk well. They are, by British standards, a fussy crop: native to warmer climates, slow to get going, and easily discouraged by a cool spring. But this year’s heatwave has changed the mood entirely. Aubergines love heat and the run of hot weather we’ve had has pushed mine on faster and more confidently than in a typical British summer. If you’ve struggled with them in cooler years, this may well be the season that finally makes them look easy.
CHOOSING YOUR PLANTS
It’s too late for this year, but it is worth knowing that aubergines are one of the crops where a grafted plant genuinely earns its higher price. Grafted aubergines – typically a favoured fruiting variety grafted onto vigorous, disease-resistant rootstock – tend to establish faster, crop more heavily, and shrug off the cooler nights and root diseases that can otherwise finish off a plant just as it’s getting interesting. For a UK greenhouse, where the growing season is shorter and less forgiving than the warmer climates aubergines evolved in, that extra vigour is not a luxury, it can be the difference between a modest harvest and a great one.
Among varieties, a few are particularly worth seeking out. ‘Black Beauty’ remains the classic for a reason — glossy, deep-purple, generously sized fruits, and a reliable performer even in an average summer. ‘Moneymaker’ (not to be confused with the tomato of the same name) is a compact, heavy-cropping variety well suited to greenhouse growing in pots or grow bags. For something different, ‘Rosa Bianca’ produces striking lavender-and-white fruits with a mild, less bitter flavour, and is a good choice if you want something a little more delicate for the kitchen. And if space is tight, the Japanese types — long, slender, thin-skinned fruits such as ‘Ophelia’ — crop prolifically.
CARE THROUGH THE SUMMER
Aubergines are hungry, thirsty plants, and July is when that becomes obvious. Water consistently – irregular watering is one of the most common causes of bitter fruit and blossom drop – and feed weekly once the first flowers appear, using a high-potash tomato feed to encourage fruiting rather than leafy growth. Greenhouse aubergines benefit from a humid atmosphere, so damping down the floor on hot days helps deter red spider mite, which thrives in dry heat.
Pinch out the growing tip once a plant reaches about 40–45cm to encourage a bushier habit, and once fruits begin to set, limit each plant to four or five at most — more than that and you’ll get a larger number of smaller, less flavourful aubergines rather than a proper crop. Support is worth thinking about too: the fruits are heavy, and a plant laden with them can topple without a cane or two to lean on. Watch for whitefly and keep an eye on the undersides of leaves for the fine webbing that signals red spider mite has moved in; both are far easier to deal with caught early.
HARVESTING
The hardest lesson with aubergines is knowing when to stop waiting. Harvest while the skin is still glossy and taut – press a fruit gently with your thumb, and if it springs back, it’s ready; if the indentation stays, it’s already moved past its best, turning bitter and seedy. Cut rather than pull, leaving a short stub of stalk attached, as the branches are brittle and easily damaged. Regular picking, rather than leaving fruits to grow as large as possible, keeps the plant producing right through until the weather turns in early autumn. I wish you a summer of many aubergines.