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 Zone 4a you can estimate when it's the best time to plant sweet peas by checking out 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.

Sweet Peas can survive in very little cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant sweet peas in Zone 4a 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. Starting your sweet peas indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4a. In the coldest months of winter you should expect an average low temperature of -30°F.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Zone 4a and it is different every year. Since half of the time in Zone 4a there is a last frost after May 15 be ready to protect your sweet peas if you have a surprise late frost.

USDA Zone Info for Zone 4a

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 Zone 4a

You may be interested in your other planting guides for Zone 4a.