How to grow Tuberous Begonia

Begonia × tuberhybrida · Begonia tuberhybrida, begonia

Summer-flowering begonias grown from tubers, with flowers 5–10 cm across in white, yellow, orange, rose, red and pink, on upright or trailing plants for beds, pots and hanging baskets. They flower until the first frosts.

Quick facts

Type	Flower
Family	Begoniaceae
Light	Partial shade
Frost	does not tolerate frost
Soil for sowing	from 10 °C
Germination	14 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow straight into the bed after your last spring frost, once the soil has warmed.

In an unheated greenhouse everything moves about three weeks earlier.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Growth	every 2 days	—	balanced (NPK), 14 days into the stage; balanced (NPK), 35 days into the stage; balanced (NPK), 56 days into the stage
Flowering	every 2 days	—	potassium, at the start of the stage; potassium, 14 days into the stage; potassium, 28 days into the stage; potassium, 42 days into the stage; potassium, 56 days into the stage; potassium, 70 days into the stage; potassium, 84 days into the stage

Open ground

Stage	Watering	Temperature	Feeding
Growth	every 2 days	—	balanced (NPK), 14 days into the stage; balanced (NPK), 35 days into the stage; balanced (NPK), 56 days into the stage
Flowering	every 2 days	—	potassium, at the start of the stage; potassium, 14 days into the stage; potassium, 28 days into the stage; potassium, 42 days into the stage; potassium, 56 days into the stage; potassium, 70 days into the stage; potassium, 84 days into the stage

At home

Stage	Watering	Temperature	Feeding
Growth	every 2 days	—	balanced (NPK), 14 days into the stage; balanced (NPK), 35 days into the stage; balanced (NPK), 56 days into the stage
Flowering	every 2 days	—	potassium, at the start of the stage; potassium, 14 days into the stage; potassium, 28 days into the stage; potassium, 42 days into the stage; potassium, 56 days into the stage; potassium, 70 days into the stage; potassium, 84 days into the stage

Growing notes

Light

Grows best in partial shade; it needs bright light to flower well, but strong sun can burn the leaves.

Soil

Moist, well-drained soil with plenty of organic matter; in pots, a well-drained potting mix.

Care

Start tubers indoors 8–10 weeks before the last frost, hollow side up and covered with 1–2.5 cm of compost, at about 18–21 °C, keeping the compost moist but not wet so the tubers do not rot. Feed a dilute fertiliser every 2–3 weeks, then a high-potassium feed every two weeks until September. Harden off and plant out in a sheltered, partly shaded spot after the last frost. Water often but not too much, and keep water off the leaves; too much water or fertiliser makes the buds drop. Lift the tubers before the first frost, dry them and store at about 7 °C. Toxic to cats and dogs, the tubers most of all.

Pests and diseases of Tuberous Begonia

Sources

Figures checked against these sources.