One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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.

The earliest that you can plant leeks in Belfast should be estimated by using the USDA zone info.

Planting Calendar for Leeks

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

Leeks are very cold tolerant which tells us that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant leeks in Belfast 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 fully mature. 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 Belfast. In the coldest months of winter you can expect an average low temperature of -15°F.

Just be sure 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 Belfast and it changes from year to year. Half of the time in Belfast last frost occurs after April 15 so make sure that you are ready to cover your leeks if you have a late frost.

USDA Zone Info for Belfast

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Belfast

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