Leek
Allium ampeloprasum
A long season crop that rewards patience and repeated hilling with a long white shank.

Start early indoors
Leeks are slow. Sow indoors ten to twelve weeks before last frost, thinly in a deep tray. Trim seedlings back to about three inches once or twice as they grow - it thickens the stems and stops them flopping.
Trench or dib
The classic method is a six-inch furrow, a seedling every six inches, watered in without filling the trench, then soil pulled in gradually as they grow. The simpler alternative is dibbing: make a six-inch hole with a dowel, drop the seedling in, and fill with water rather than soil, letting the hole collapse on its own.
Blanching is the whole technique
The edible white shank is stem that never saw light. Hill soil up around the plants every few weeks. No hilling, no shank - you get an onion-flavoured green stick instead. Try to keep soil out of the leaf joints as you go.
Feeding and water
A big plant on a long season and a heavy feeder. Side-dress with nitrogen monthly. Leeks never want to dry out - drought produces thin tough shanks and can trigger bolting.
Pests
Onion thrips cause silvery streaking in hot dry spells; a strong hose spray helps. Leek moth and allium leaf miner are spreading through parts of the region and tunnel the shanks - floating row cover from planting is the reliable defence where they occur. Rotate away from other alliums.
Leave them in the ground
Leeks are among the hardiest things you can grow, hold well past frost, and sweeten as they go. Harvest through early winter as needed and mulch deeply if hard freezes are forecast so you can still get a fork in.
Grit
Soil works between the leaves during hilling. Split the shank lengthwise and rinse under running water, fanning the layers - washing a whole intact leek does not work.
Harvest and storage
Lift with a fork rather than pulling, which snaps the shank. They keep best in the ground; lifted, they hold a few weeks somewhere cold and damp. Sliced leeks freeze well and the tough green tops make excellent stock.
- Days to harvest
- 100-150
- Start indoors
- 10-12 wks pre-frost
- Spacing
- 6 in
- Row spacing
- 12-18 in
- Sun
- Full
- pH
- 6.0-7.0
- Frost
- Very hardy, to ~5F
- Water
- Steady, never dry