One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to estimate when to plant leeks by referring to the USDA zone info for London.

Planting Calendar for Leeks

Frost tolerance for leeks:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since leeks are one of those plants that can tolerate quite a bit of cold weather you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant leeks in London is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant leeks and expect a good harvest is probably September. Any later than that and your leeks may not have a chance to grow to maturity. Starting your leeks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in London. It might get as low as -10°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for London and it is different every year. Since half of the time in London you get a frost after April 15 be ready to protect your leeks in the event of a surprise late frost.

USDA Zone Info for London

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in London

You may be interested in your other planting guides for London.