Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Billings you can estimate when it's possible to plant sweet peas by looking at the USDA zone info.

Planting Calendar for Sweet Peas

Frost tolerance for sweet peas:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since sweet peas are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other frost tender plants.

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

The last month that you can plant sweet peas and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sweet peas may not have a chance to fully mature. Starting your sweet peas indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Billings. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Billings is just an average the actual date of last frost changes from year to year. Since half of the time in Billings it frosts late in the year after May 15 be ready to protect your sweet peas in the event of a 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.