One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

By reviewing the USDA zone info for Johnston it's possible to figure out when it's a good idea to plant sweet peas.

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 a bit earlier in the year than other frost tender plants.

The earliest that you can plant sweet peas in Johnston 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 sweet peas and expect a good harvest is probably August. Any later than that and 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 couple of weeks earlier.

Last Frost Date

In Johnston the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Johnston and it will vary from year to year. Since half of the time in Johnston you get a frost after April 15 be ready to cover your sweet peas in the event of a late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

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