By our calculations, you should look at sowing White Hailstone about 28 days before your last frost date.
Sow in stone-free soil in early spring to early summer, and agin in late summer for fall crop. Thrives in cool seather. Make successive sowing every 2 weeks.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as White Hailstone is a half hardy plant.White Globe, White Button