TL;DR
Leeks are a cool-weather crop, and they appreciate a frost or two for better flavor development.3 A hard freeze can damage them, so watch the forecast.3 You can grow leeks from scraps or from seeds.5
Leeks look like a bigger, fatter green onion, and they like the cold.3 This practical guide covers the parts of a leek, the temperatures it prefers and how to start it.
Know Your Leek
Leeks (Allium porrum) are sometimes called the gourmet's onion.2 They are related to onions and garlic, but they have flat leaves instead of tubular ones and relatively little bulb development.2
A leek is considerably fatter than a scallion, at one to three inches wide.3 Its flavor is mild, sweet and onion-like, and cooks use it to season many dishes.3
Practical Leek Steps for November
Step 1: Learn the parts
The topmost, leafy green part of the plant is called the flag.3 The white part is usually called the stem or stalk, though botanically those names are not quite right.3
Step 2: Match the weather
Leeks have an ideal growing-temperature range of 55 to 75°F.3 Temperatures inside that range suit leeks best.3
Step 3: Welcome a frost
Leeks appreciate a frost or two for better flavor development.3 So a light autumn frost works in your favor.
Step 4: Watch for a hard freeze
A hard freeze can cause damage and dieback in leeks.3 Check the forecast in late autumn so a sudden cold snap does not catch you off guard.
Step 5: Check your variety
Most varieties are hardy, and some types can tolerate cooler weather.3 Read the seed packet or plant label to see how hardy your variety is.
Step 6: Choose how to start
You can grow leeks from scraps or from seeds.5 Some gardeners treat leek planting as part of their winter planting.4
Safety and Care
If you add any fertiliser or pest treatment to your leek bed, follow the product label and your local rules.
Your Next Step
Walk your leek bed this week. Find the flag and the white stem on each plant, and check your seed packet for how hardy your variety is.