Wish I knew. alot of my seeds dont sprout or only last a little where as the first few years sowing them they did beautifully... Actually- a few or more seeds doesn't grow or sprout for me from when I started gardening. Baby Blue Eyes, portulacas, babys breath, snapdragons, annual phlox, to name a few. They just don't, very frustrating though I plant every year- am disappointed. The named above were like 'my first loves' flowers. I really don't understand why not but will continue trying....