Brussels sprouts grow in temperature ranges of 7–24 °C (45–75 °F), with highest yields at 15–18 °C (59–64 °F). Fields are ready for harvest 90 to 180 days after planting. The edible sprouts grow like buds in helical patterns along the side of long, thick stalks of about in height, maturing over several weeks from the lower to the upper part of the stalk. Sprouts may be picked by hand into baskets, in which case several harvests are made of five to 15 sprouts at a time, or by cutting the entire stalk at once for processing, or by mechanical harvester, depending on variety. Each stalk can produce , although the commercial yield is about per stalk. Harvest season in temperate zones of the northern latitudes is September to March, making Brussels sprouts a traditional winter-stock vegetable. In the home garden, harvest can be delayed as quality does not suffer from freezing. Sprouts are considered to be sweetest after a frost.