We usually plant these in the fall and they begin to grow but don't do much until the weather warms up in the springtime. They certainly overwinter here and I understand that by planting them now, they get a head start and the black aphids aren't so much of a problem.

The variety recommended for overwintering here is Aqua Dulce Claudia. We call them broad beans, rather than favas, and have a number of varieties available. You don't want the plants to be more than 3 -4 inches high at the onset of winter. The main problem I get is rots of various types rather than frost damage. The other problem is mice which will dig up and eat the seed just as it germinates. Although not vital the plants do better if protected and stay cleaner if you can give them a covering of fleece. Some years they are well ahead of spring sown plants, others there's not much difference. The difference is even less if you start some plants indoors in a cool porch or windowsill.