Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when it's possible to plant delphinium by looking at the USDA zone info for American Canyon.

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.

Delphinium do ok in very little cold which means that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant delphinium in American Canyon 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 grow to maturity. If you are starting your delphinium indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on February 15 in American Canyon. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for American Canyon is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in American Canyon it frosts late in the year after February 15 be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for American Canyon

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 American Canyon

You may be interested in your other planting guides for American Canyon.