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Types of Leeks
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Leeks (Allium ampeloprasum) are a
non-bulbing member of the Amaryllidaceae family, which includes garlic,
onions, chives and scallions.
- European Leeks are short and thick stemmed.
- Turkish Leeks are long and thin stemmed.
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Soil and Nutrient Requirements
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Well
drained soil with high fertility and pH 6.2-6.8 will grow the best leeks.
They do not tolerate acid soil especially as young seedlings. 80 lbs/A
nitrogen is recommended. Sidedress 4-5 weeks after planting. Weed free raised
beds are ideal.
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Position
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Full
sun/partial shade.
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Seeding Depth
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1/4
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Seeding Rate
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6
seeds/ft
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Plant Spacing
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Thin to
6
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Row Spacing
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24
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When to Sow
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Days to
maturity are from transplanting; add 20-30 days if direct seeding. Direct seed soon as soil can be worked
outdoors or into a cold frame or start transplants 10-12 weeks before
planting date, sowing seeds thickly into flats, Ό apart or into 1.5 plugs.
Transplant when plants reach 10-16 tall planting 6 deep, with only a few
inches of leaves need to be remaining above the soil
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Other Considerations
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For
longer, blanched stalks, hill soil around the plants at least two times
during the summer. Leeks compete poorly with weeds.
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Frost Tolerant
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Yes. Some
varieties can overwinter even in cold climates.
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Drought Tolerant
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Leeks
need plentiful, even moisture for good yields.
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Heat Tolerant
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Leeks
grow best in cool to moderate conditions.
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Seed Specs
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9,500-11M
seeds/oz (10, 250 avg.). M=1,000, MM=1,000,000
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Harvest
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Harvest
at any stage of maturity, but flavor is usually best in fall after a few cold
nights. Some fall planted varieties may even overwinter for an early spring
crop.
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Storage
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Leeks can
be dug up and hilled in into a root cellar or cold storage area. At around 35
degrees, they will keep in this way for a few months.
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Pest Info
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- Onion Thrips thrive in hot
dry weather and can be discouraged by heavy rain or overhead irrigation.
Lacewing larvae, pirate bugs and predatory thrips are natural predators.
- Onion Maggots overwinter in
the soil. They feed on the roots of young seedlings, causing wilting and
sometimes seedling death. Crop rotation and beneficial nematodes can be
helpful.
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Disease Info
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- Botrytis leaf blight (Botrytis squamosa) develops as
small lesions surrounded by a silvery-white halo that grow and
eventually extend through the wall of the leaf. Infection by the more
common Botrytis cinerea (gray
mold fungus) is distinguished by smaller lesions that do not have a
halo and do not penetrate the leaf. Die-back begins at the leaf tip
and can result in premature death of the leaf prior to bulb maturity.
The fungus persists as sclerotia in the soil and on crop residues.
Protectant fungicides are applied in advance when cool, wet conditions
are expected.
- Downy Mildew (Peronospora destructor) thrives
in extended periods of cool, humid weather. Plant in a well drained
area, avoid overhead irrigation, orient rows with prevailing winds and
rotate crops.
- Purple blotch (Alternaria porri and Alternaria
alternata) appears as elongated purple lesions that turn silvery
over time. Control measures are similar to those for botrytis blight and
downy mildew. Yellow cooking onions are not as susceptible to purple
blotch as are Spanish onions. Best prevention methods are to practice
good sanitation -- never pile cull onions near onion fields -- and crop
rotation with non-host plants.
- Damping off (Pythium/Rhizoctonia) Avoid
excessive moisture.
- White Rot (Sclerotium Cepivorum) Destroy
infected plants and rotate crops.
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Seed Saving Info |
