‘Lemons are far tougher than they look.’ Photograph: Alamy
I bought my lemon tree from Lidl. Well, haggled would be more accurate. My friend Birgit negotiated a discount for what was essentially a stick with no leaves. I paid a fiver and was pleased as punch, but the rest of the queue was confused: it really did look dead.
Lemons are far tougher than they look, but if kept in low light for any length of time, and slightly abused on the watering front, they tend to drop their leaves. If a gentle scratch to the stem reveals green under the outer layer, all is not lost. I took mine home, pruned it hard, watered it and fed it, and it flourished.
The difficulties started once winter came. Where was this large lemon to live when the temperatures dropped? This is an age-old problem: ever since the Medicis fell headlong for citrus in the 15th century, we’ve been dragging heavy pots indoors to overwinter lemons in less-than-warm climes.
Early limonias, or lemon houses, were very dingy places. Glass panes were at the time very expensive and very small, so a limonia was less of a glasshouse and more a shed with huge wooden shutters that were opened during the day and closed at night. Also, some poor gardener would have to keep fires going all night so the frost didn’t creep in.
Italian lemons that are still wintered in such Renaissance rooms emerge pale, weak versions of their former selves, but at least they have a summer of good sun to perk them up. Ours don’t have that luxury. And a winter in the dark followed by a less-than-sunny summer spells doom for a lemon tree.
Over winter, you ideally want to keep them at a night-time temperature of 10C and in as much light as possible. For a while, I abused my lemon by keeping it in an unheated greenhouse, where temperatures plummeted to zero: the lemon survived, but only just. Now it spends the winter on the sunny kitchen windowsill, which makes for a far happier plant.
The trick is to avoid overwatering in winter, when there is very little growth. However, all citrus like humid conditions, so sit the pot in a tray filled with water and gravel, with the base of the pot sat just above the water level. Never let a citrus sit in a saucer of water: the roots rot quickly, and overwatering is the quickest way to kill a citrus plant.
Citrus are hungry plants and need regular feeding. You can buy specific citrus feeds, but I improvise using a seaweed and chicken manure year-round, supplementing with comfrey and nettle feed in summer. The trick is high nitrogen during the growing season. With luck, you should be picking lemons by autumn.