Growing Leeks in Zone 3B

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 3B has a short growing season — start seeds indoors when possible and use season-extending techniques like cold frames and row covers.

Top Growing Tips

• Start indoors 10-12 weeks before last frost — one of the earliest starts needed
• Transplant into narrow holes 6 inches deep; drop seedling in and let soil fill naturally
• Mound soil around the shank as plants grow to blanch and lengthen the white portion
• Tolerates light freeze and can be mulched to extend harvest into December
• Harvest after first frost for the sweetest, most complex flavor

Companion Planting

Good companions: carrots, celery, onions, brassicas

Avoid planting near: legumes (beans, peas)

Harvest Timeline

100-120 days from transplant; harvest when shank is 1 inch or more in diameter

About Zone 3B

USDA Hardiness Zone 3B has an average last spring frost around May 15 and first fall frost around Sep 15. 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.