One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant delphinium in Suisun City can be figured out by referring to the USDA zone info.

Planting Calendar for Delphinium

Frost tolerance for delphinium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant delphinium a bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant delphinium in Suisun City 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 delphinium and expect a good harvest is probably September. Any later than that and your delphinium may not have a chance to fully mature. Starting your delphinium indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Suisun City and it is different every year. Since half of the time in Suisun City it frosts late in the year after February 15 be ready to cover your delphinium in the event of a surprise late frost.

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.