One of the first steps you take when you are figuring out 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.

In Helena you can figure out when it's a good idea to plant leeks by referring to 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.

Since leeks are very cold tolerant you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant leeks in Helena 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. You probably don't want to wait any later than that or else your leeks may not have a chance to fully mature. If you are starting your leeks indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Helena. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Helena there is a last frost after March 15 be ready to protect your leeks if you have one of those late frosts.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Helena

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