Zinnia - Early Wonder This variety features large dahlia-like blooms and makes one of the showiest mixtures for borders and cutting, reaching the height of 75cm. Sow outdoors where they are to flower, 0.5cm deep, directly into finely prepared soil which has already been watered. Seedlings usually appear in 14-28 days. Thin seedlings to 30cm apart. Water well until plants are established. Or sow indoors in trays of compost. Water well and place in a greenhouse or cold frame. Keep moist. Transplant seedlings 5cm apart to other trays when large enough to handle. Always hold seedlings by a leaf, never by the stem. Gradually accustom young plants to outside conditions, avoiding frosts, before planting out 30cm apart.