When to sow: Apr-June
Zinnia tips: Zinnias do not like the cold so do not sow them too early. They also do not like having their roots disturbed.
Direct (recommended): wait until soil has warmed (mid May), sow every 5cm in drills 30cm apart and thin to final spacing.
Modules: sow beginning April and transplant into final position mid May. Tall varieties may need staking.