The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when it's possible to plant delphinium is to use the USDA zone info for Sullivan.

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 very little cold which tells us that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant delphinium in Sullivan 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. You probably don't want to wait any later than that or else your delphinium may not have a chance to fully mature. If you are starting your delphinium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Sullivan the average date of last frost happens on April 15. It might get as low as 5°F during the coldest months of winter.

Always keep in mind that USDA zone info for Sullivan may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Sullivan you get surprised by a frost after April 15 be ready to cover your delphinium in the event of a surprise late frost.

USDA Zone Info for Sullivan

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Sullivan

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