Shop at deodar-seeds.com 
About this seed
Do not bury the seed
Sweet alyssum seed needs light to germinate. Cornell Cooperative Extension says not to cover the seed, and Clemson Home and Garden Information Center says to cover it only lightly. Press the seed onto a moist, fine seed mix and keep it at 18–21 °C; Cornell gives 14 days to emergence.
When to sow
Sow indoors 4 to 8 weeks before planting out (Cornell says 4–6 weeks before the last frost; Clemson says 6–8 weeks before planting outdoors), or sow outdoors several weeks before the last spring frost. Clemson also sows in September for flowers from autumn into winter, in climates where that works. Seed-grown plants flower within 6 to 8 weeks.
Heat is the limit
Sweet alyssum is a cool-season annual. Clemson notes that plants grown from seed may stop flowering as summer temperatures rise, unlike sterile hybrids. Give it full sun to part shade, with some afternoon shade in hot climates, and well-drained soil with regular watering.
Size
Seed-grown plants reach 8–15 cm high and spread 30 cm or more (Clemson), a low edging rather than a tall flower.
What the packet is
The packet holds 100 seeds sold as Alyssum mix. The figures above are for sweet alyssum, Lobularia maritima, which is how this mix is listed. The colour balance, fragrance and cultivar names of the mix are not specified and no germination percentage is claimed.