Giant Musselburgh

Leek

120d to harvest

Sweet, mild, and richly aromatic—Giant Musselburgh leeks unfurl into long, tender stalks with a creamy, pale core that feels silky between the fingers. Expect a substantial, upright growth habit and a satisfying bite that turns beautifully mellow when roasted or simmered, making them a standout for hearty dishes and elegant sauces. A classic market-class choice for gardeners who love dependable performance and impressive size at 120 days.

Crop Dates

Growing note: In frost-free Zone 10a, grow this cool-season crop during the cooler dry season (October–February).

Milestone	Date
Start Indoors	—
Climate	Frost-Free Climate
Transplant / Sow Outdoors	Oct 1st
Harvest Begins	Jan 29th
Harvest Ends	Feb 28th

Crop Details

Trait	Value
Days to Maturity	120
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	45
Min Night Temp (°F)	35
Harden Off (days)	7

Frequently Asked Questions

What pest or disease is most common on Allium porrum (giant leek) and how do I control it?

Leek moth (Crocidomorphus/Plutella-related pests) is a common problem: larvae bore through the stalks and leave frass trails. Start with tight weed-free beds and use fine insect netting as soon as plants are established; remove and destroy heavily damaged leaves. If you see ongoing damage, apply an approved Bt (Bacillus thuringiensis) product labeled for lepidopteran caterpillars and re-apply according to label intervals.

How often should I water Allium porrum during the main growing phase?

During the 60–110 day growing window (after seedlings establish), keep the soil consistently evenly moist but never waterlogged—aim for about 1 inch (2.5 cm) of water per week split into 1–2 deep sessions. Water more frequently during hot spells so the inner leaf bases don’t dry out; leeks are sensitive to irregular moisture that can lead to thin, woody stems. Check by feel: the top few inches should be moist and crumbly, not dry or soggy.

How can I tell when Giant Musselburgh leeks are ready to harvest?

Harvest when stems reach the cultivar’s expected size and the plants are firm, with a full, white-to-light-green “blanched” portion from earthing up. For Giant Musselburgh, start checking at about 120 days after sowing/transplanting; you can lift earlier for smaller sizes but wait for thicker stems for best quality. Stop harvest before heavy freezes; cut the roots cleanly and leave some leaf length for easier handling.