How to grow Mandarin

Citrus reticulata · mandarin orange

The mandarin is a small evergreen citrus tree, up to about 7.6 m in the open, grown for its sweet, easy-to-peel fruit. It is tender and easily damaged by cold, so outside frost-free regions it is grown in a pot that winters indoors or in a greenhouse.

Quick facts

Type	Fruit tree
Family	Rutaceae
Light	Full sun
Soil pH	5.5–6.5
Frost	does not tolerate frost
Sowing to harvest	1095 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Planted as a young plant from a nursery while it is dormant — in early spring before the buds open, or in autumn after leaf fall.

Harvest from October to December (northern hemisphere).

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Growth	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage; nitrogen, 28 days into the stage; nitrogen, 42 days into the stage
Flowering	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage
Fruiting	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage; nitrogen, 28 days into the stage; nitrogen, 42 days into the stage; nitrogen, 56 days into the stage; nitrogen, 70 days into the stage; nitrogen, 84 days into the stage
Harvest	every 14 days	10…18 °C	balanced (NPK), at the start of the stage
Winter rest	every 14 days	10…18 °C	balanced (NPK), at the start of the stage; balanced (NPK), 30 days into the stage; balanced (NPK), 60 days into the stage; balanced (NPK), 90 days into the stage

Open ground

Stage	Watering	Temperature	Feeding
Growth	every 14 days	—	nitrogen, at the start of the stage
Flowering	every 14 days	—	—
Fruiting	every 14 days	—	nitrogen, at the start of the stage
Harvest	every 14 days	—	—
Winter rest	every 42 days	—	—

At home

Stage	Watering	Temperature	Feeding
Growth	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage; nitrogen, 28 days into the stage; nitrogen, 42 days into the stage
Flowering	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage
Fruiting	every 7 days	13…29 °C	nitrogen, at the start of the stage; nitrogen, 14 days into the stage; nitrogen, 28 days into the stage; nitrogen, 42 days into the stage; nitrogen, 56 days into the stage; nitrogen, 70 days into the stage; nitrogen, 84 days into the stage
Harvest	every 14 days	10…18 °C	balanced (NPK), at the start of the stage
Winter rest	every 14 days	10…18 °C	balanced (NPK), at the start of the stage; balanced (NPK), 30 days into the stage; balanced (NPK), 60 days into the stage; balanced (NPK), 90 days into the stage

Growing notes

Light

Give it the brightest spot you have, at least 6–8 hours of direct sun, such as a south or south-west window; it can stand outdoors in summer once nights stay above 10 °C.

Soil

Use a quick-draining, slightly acidic potting mix (pH 5.5–6.5) in a pot with good drainage holes; never leave the pot standing in water.

Care

Water thoroughly when the top 5–7 cm of the mix are dry, which in hot weather can mean almost daily; in winter let the surface dry partly before watering. From spring to early autumn feed every two weeks with a nitrogen-rich citrus feed with trace elements, and in winter switch to a balanced winter citrus feed. Keep it at 13–29 °C while growing and rest it at about 10–18 °C in winter; bring it in before nights drop below about 10 °C. Most citrus pollinate themselves, but tangerines need cross-pollination. Thin branches in February and pinch back new shoots in summer.

How to tell it is ripe

The fruit has reached full size with a rich orange, yellow-orange or red-orange skin.
The skin looks pebbly and the loose peel sits lightly on the fruit.
Colour alone is not a reliable sign; satsumas can be good to eat while still partly green.
Taste one fruit; tasting is the only sure way to tell a citrus fruit is ripe.
A ripe mandarin feels firm to slightly soft and heavy for its size.
Clip ripe fruit off with pruning shears instead of pulling it, and leave the rest on the tree, where they keep getting sweeter until they start to drop.

Sources

Figures checked against these sources.