Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Mount Vernon can be used to estimate when it's the best time to plant delphinium.

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 more sensitive plants.

The earliest that you can plant delphinium in Mount Vernon is March. However, you really should wait until April 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. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

In Mount Vernon the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that USDA zone info for Mount Vernon is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Mount Vernon you get a frost after April 15 so be sure to be ready to protect your delphinium in the event of a late frost.

USDA Zone Info for Mount Vernon

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Mount Vernon

You may be interested in your other planting guides for Mount Vernon.