The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to estimate when it's the best time to plant delphinium by checking out the USDA zone info for Tolleson.

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 well in some cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Tolleson 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 really do well. 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

The average date of last frost is February 15 in Tolleson. In the coldest months of winter you should expect an average low temperature of 25°F.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Tolleson and it can change quite a bit from year to year. Half of the time in Tolleson you get surprised by a frost after February 15 so be sure to be ready to cover your delphinium in the event of a surprise late frost.

USDA Zone Info for Tolleson

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 Tolleson

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