Growing Leeks in Zone 4B

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 4B 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 4B

USDA Hardiness Zone 4B has an average last spring frost around May 1 and first fall frost around Oct 1. 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.