At northern or southern latitudes, day length becomes less than ten hours during winter. During the months with day-length less than ten hours (the so-called Persephone period) plant growth all but stops, yet mature plants may remain healthy. Many types of salad greens can be planted in the fall such that they become mature and ready for harvest in mid-winter. The best planting dates are determined by when the Persephone period begins at your latitude. Based on this information, Johnny's Selected Seeds has published a useful chart recommending appropriate fall planting dates. However, that chart is somewhat cumbersome to use. Here I present a database that automatically does the calculations to find the best fall planting dates for your location.