One of the best tools that you have as gardeners to help us determine 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.

A common way of making a decision about when it's possible to plant sweet peas is to look at the USDA zone info for Napa.

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 plants that might not handle the cold.

The earliest that you can plant sweet peas in Napa 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 sweet peas and expect a good harvest is probably September. 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 little bit earlier.

Last Frost Date

On average the last frost is on February 15 in Napa. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Napa is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Napa it frosts late in the year after February 15 so make sure that you are ready to cover your sweet peas if you have one of those late frosts.

USDA Zone Info for Napa

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Napa

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