One of the best tools that you have as gardeners to help us figure out 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 getting a good idea when to plant delphinium is to use the USDA zone info for Shafter.

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 slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant delphinium in Shafter 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. You can get started a few weeks earlier by starting your delphinium indoors.

Last Frost Date

In Shafter the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 20°F.

Since the USDA zone info for Shafter is not always accurate the actual date of last frost will vary from year to year. Half of the time in Shafter you get a frost after February 15 so just be sure to be ready to cover your delphinium in the event of a surprise late frost.

USDA Zone Info for Shafter

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°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 25°F.

Plants to Grow in Shafter

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