One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

You can figure out when it's possible to plant delphinium in Jamestown by reviewing 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.

Delphinium do ok in some cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Jamestown 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. If you wait any later than that and your delphinium may not have a chance to grow to maturity. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Jamestown. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Jamestown may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Jamestown there is a last frost after May 15 so always be ready to protect your delphinium if you have one of those late frosts.

USDA Zone Info for Jamestown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Jamestown

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