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

The first chance to plant delphinium in Wahpeton should be figured out by looking at 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.

Since delphinium are barely cold tolerant you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant delphinium in Wahpeton 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. 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 little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Wahpeton. In the coldest months of winter you can expect an average low temperature of -30°F.

Keep in mind that USDA zone info for Wahpeton is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Wahpeton you get a frost after May 15 so always be ready to protect your delphinium if you have a surprise late frost.

USDA Zone Info for Wahpeton

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 Wahpeton

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