Lobularia maritima. Sweet Alyssum makes an excellent cover crop for weed suppression and for attracting beneficial insects. A very large range of predatory wasp species are attracted to its tiny flowers, and will feed on caterpillars, aphids, and other pest insects while they are in the area. Sow Alyssum liberally between rows of lettuce, carrots, or Brassicas to smother potential weeds and generally improve the garden ecosystem. Once it is tilled under it will release useful carbon and organic matter.
Sow 30g (1 oz) per 1,000 square feet, or 454g (1 lb) per acre. Sow on the soil surface and keep moist until established.