Instructions for Growing Leeks As An Early and Late Crop In The Vegetable Garden

You can grow leeks in one of two ways – either as an early spring crop similar to onions or as a late season crop by direct sowing into the garden.

Early Crop

For the early crop, sow seed in pots or flats as thinly as possible.

Do this approximately six to eight weeks before you want to transplant them outdoors. Late April is a good time for outdoor planting in zone 4 so the seeding date is the beginning of March. Sow seed one quarter inch deep, cover the seed and gently firm the soil.

Keep the soil temperature at 65-70F and you should see a germination rate of 75% or so within two to three weeks.

This seed does not germinate as quickly as onions nor does it germinate as completely as onions do. If you have the ability to cool the seeds down at night, you'll find they germinate a little bit better. So day germination temperatures around 70F and night temperatures around 60F will give you optimum germination.

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The Tops

There are two schools of thought about the tops. The first says to trim the tops off – cut the leek halfway back – when it gets to four to five inches tall. The thinking is that this bulks up the root and makes transplanting better. This is the time-honoured method.

A second school says not to cut back the tops as this retards the performance in the garden and this has been suggested by at least one ag study.

Whichever you pick (I never cut them back after I read the article) after they germinate, you want to grow them at 50F to keep them short and blocky. Higher temperatures will indeed cause them to get too tall and perform badly in the garden.

Feeding Leeks

Feed every week with a balanced fertilizer to keep them growing strongly.

As soon as you can get onto the garden (late April) transplant them outside. The way to do this is to dig a six inch deep furrow and plant the leeks at the bottom of this furrow or trench. Over the course of the growing season, the trench is gradually filled in when you cultivate near the leek. This will blanche the leek. Seedlings should be planted approximately four to six inches apart. Thinnned to six inches when the crop gets really growing.

Note that leeks like rich, fertile soil so adding compost is necessary if you want a great crop. They also do not like being water starved so plan on feeding and watering this crop for best results.

Late Crop

If you want a late crop, dig the furrow and plant the seed directly into the furrow Plant one seed to the inch and thin to the strongest seedling every six inches. This can be done from the end of April to June to get a crop to harvest in the fall. Remember that you have to keep the seed damp if you want germination.

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Harvesting Leeks

Leeks are usually dug in October before a really hard frost softens them. They are usually used fresh although storage in frost free conditions will keep them for a long time. I'm told if you keep the frost away from them and bank them up with straw that they'll start growing again the following April which will make them very early to harvest and eat. Given our zone 4 climate, I've never done this. I'd have to move the leeks about 500 miles straight south to stop frost.

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