May is the time to be sowing those varieties that over winter well. There are heaps to choose from (the collections above) but here are some favourites:

Cool
Chococlate Lace
Radish
Eucalyptus Cinerea Silver Dollar
Cornflower 
Anemone De Caen Blue Bicolour Corm

Temperate
Strawflower
Scabiosa
Sea holly
Calendula
Beetroot

Arid
Statice
Larkspur
Carnation
Carrot
Chives

Sub tropical 
Cosmos
California poppy
Nasturtium
Amaranthus 
Eggplant

Tropical
Zinnia
Rudbeckia
Basil
Paper daisy
Kennadia coral pea

Various factors can influence germination, including light, temp, depth and more. If you have every had trouble you may want to read this.

Mitch Thiessen, The Agrarian Kitchen Gardens head gardener, shares his thoughts on building soil health.