Before planting it is a good idea to find your USDA Zone info to figure out 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.

A way of determining when it's the best time to plant sweet peas is to use the USDA zone info for Havre.

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.

Sweet Peas are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant sweet peas in Havre 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. If you wait any later than that and your sweet peas may not have a chance to really do well. You can get started a couple of weeks earlier by starting your sweet peas indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Havre. It might get as low as -30°F during the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Havre and it will vary from year to year. Since half of the time in Havre you get a frost after May 15 be ready to protect your sweet peas if you have a late frost.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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