heat-treated To Halt The Boltearly-to-harvestf 1 Generation Hybrid For Vigorous Plantsa superb & Handsome Chestnut-skin Onion Producing One Of The Earliest Crops From A Spring Planting.we Treat These Sets With Heat For 20 Weeks Prior To Arriving With You. This Prevents Your Onions From Bolting (going To Seed) So That All The Energy In Your Plants Go Into Making Bigger, Better-flavoured Bulbs.fen Early keeps Much Better Than Other Early Types Too So You Can Store Them- Hang Them Up In Plaits In Cool & Dry Locations Like A Porch Or Air-tight Garden Shed until The End Of Winter For A Supply Of Flavoursome Onions During The Cold Months.