Leeks are the mildest, most cold-hardy member of the allium family. They can overwinter in the ground in zones 5+ and provide harvests well into winter when other crops have finished.
Zone 7B enjoys a long growing season. You can often get two plantings of cool-season crops (spring and fall).
Good companions: carrots, celery, onions, brassicas
Avoid planting near: legumes (beans, peas)
100-120 days from transplant; harvest when shank is 1 inch or more in diameter
USDA Hardiness Zone 7B has an average last spring frost around Mar 28 and first fall frost around Nov 3. All planting dates above are calculated from these frost dates. Your specific location may vary — check with your local extension office for the most accurate dates.