Lesson 2
Planting tubers
Start tubers indoors in March (mild regions) or April (cooler). Pot one tuber per 3-litre pot in fresh compost, with the old stem pointing up and the 'crown' (where shoots emerge) just visible. Water once and don't water again until shoots appear.
Once shoots are 5–8 cm tall and all frost danger is past, transplant into final containers: one plant per 30 L tub minimum (40 L for dinner-plate types). Insert a stout cane immediately — pushing one in later spears the tuber.
From tuber to final pot
- 1Late winter: store dormant tubers in dry compost, cool and dark.
- 2Early spring (8 weeks before last frost): pot up shallow, in 3 L, just water once.
- 3Mid spring: shoots emerge — light, cool, careful watering.
- 4After last frost: harden off 5 days, then transplant to final 30–40 L pot with cane.
- 5Pinch the leading shoot at 5 leaf pairs to make a bushier plant with more flowers.