Mandarin

Before the first frost (October to November), bring the mandarin into bright, cool winter quarters at about 5 to 10 °C, for example a frost-free stairwell with a window, a cool conservatory or a frost-free greenhouse. Water much more sparingly than in summer, but never let the root ball dry out completely, and only slowly put it back outside after the Ice Saints in mid-May.

Sowing (only for the experimentally minded, not true to type): Take the seeds from a ripe mandarin, rinse them briefly and insert them about 1 cm deep into a mix of seed compost and sand. Keep the substrate evenly moist and put the pot somewhere warm (at least 20 °C) without direct sun. Germination takes several weeks. Bear in mind: seedlings are rarely true to type. Fruit can differ greatly from the mother plant in taste and yield, and the first fruit takes 5 to 7 years to appear.

Cuttings (recommended for home gardeners): In spring after growth starts, or in early summer, cut slightly woody shoots about 15 cm long, with a slanting cut just below a leaf node. Remove the lower leaves and leave 2 to 3 at the top. Insert the cutting into an airy mix of seed compost and sand, pull a clear plastic bag over it to raise the humidity, and ventilate every few days. Put it bright but without direct midday sun, at room temperature, and keep the substrate moist, not wet. Rooting takes several weeks to months and is not guaranteed. Patience is called for. Cuttings are genetically identical to the mother plant and often flower as early as one to two years after rooting.

Grafting (most professional method, true to type): For true-to-type fruit, grafting onto a robust rootstock is the most reliable method. Poncirus trifoliata (trifoliate orange) is particularly suitable as a rootstock; it is considerably more frost-tolerant than most citrus rootstocks, easy to grow from seed and widely available in German nurseries. Grafting is usually done in summer by budding (T-cut) or the beginner-friendly chip budding: cut a bud from a healthy shoot of the variety you want and insert it into the prepared cut on the rootstock stem. Wrap the spot airtight with grafting tape. After about 3 to 4 weeks, the bud starting to grow shows success. The rootstock gives the plant cold tolerance and robustness; with Poncirus a typical bulge can form at the graft union.

Note: Air layering of a slightly woody branch also works with citrus and gives true-to-type plants that flower early, but for beginners it is more laborious than cuttings.