Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Billings should be reviewed to figure out when to plant leeks.

Planting Calendar for Leeks

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

Leeks tend to make it in pretty solid cold which tells us that you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

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

The last month that you can plant leeks and expect a good harvest is probably August. You probably don't want to wait any later than that or else your leeks may not have a chance to fully mature. You can get started a little bit earlier by starting your leeks indoors.

Last Frost Date

The average date of last frost is May 15 in Billings. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Billings is not always accurate the actual date of last frost changes from year to year. Since half of the time in Billings you get a frost after May 15 be ready to cover your leeks in the event of a surprise late frost.

USDA Zone Info for Billings

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Billings

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