One of the first steps you take when you are determining your gardening schedule is find your 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 way of figuring out when it's possible to plant erysimum is to consult the USDA zone info for Suisun City.

Planting Calendar for Erysimum

Frost tolerance for erysimum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since erysimum do well in moderate cold you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant erysimum in Suisun City is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant erysimum and expect a good harvest is probably October. Any later than that and your erysimum may not have a chance to really do well. If you are starting your erysimum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Suisun City the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Suisun City is an average the actual date of last frost will vary from year to year. Since half of the time in Suisun City you get surprised by a frost after February 15 be ready to protect your erysimum if you have one of those late frosts.

USDA Zone Info for Suisun City

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 Suisun City

You may be interested in your other planting guides for Suisun City.