The USDA Zone info is a great tool for gardeners to help us figure out 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.

A way of estimating when it's the best time to plant delphinium is to examine the USDA zone info for Powell.

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 tend to make it in some cold which tells us that you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Powell is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant delphinium and expect a good harvest is probably August. You probably don't want to wait any later than that or else your delphinium may not have a chance to really do well. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Powell the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Powell may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Powell last frost occurs after May 15 be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Powell

Here is the info for USDA Zone 4b.

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

Plants to Grow in Powell

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