Cook the grated carrots in boiling water for 5 minutes and drain in a sieve. Return carrots to the pot and add the sugar, lemon rind, lemon juice, and candied gingerroot.

Bring the mixture to a slow boil, stirring until the sugar dissolves. Continue cooking over low heat, stirring frequently, for 1 1/2 hours. Remove from heat when a candy thermometer reads 220 degrees F., or when the liquid runs off a spoon as a thick syrup.

Carefully spoon the marmalade into hot sterilized jars, filling to within 1/4 inch of the top. Wipe the rims clean and seal the jars with the lids. Process the jars for 10 minutes according to usual canning method.