In a 4- to 5-quart pot over medium heat, combine 4 cups water with the sugar, lemon peel, ginger, cardamom, and vanilla scrapings.
Bring the mixture to a boil.
Cook until the sugar dissolves, and then reduce heat to low.
Simmer, uncovered, until the liquid has thickened slightly, about 10 minutes.
Add the apricots to the pan.
Rinse a double thickness of cheesecloth under cold water, and drape it over the apricots so all the fruit is covered by the cloth and submerged in the liquid.
Continue simmering until the apricots soften slightly, 2 to 4 minutes.
Remove from heat, and let cool completely.
Use immediately, or transfer the apricots and poaching liquid to a storage container.
Make sure the apricots are completely submerged in the liquid.