Before planting it is a good idea to find your USDA Zone info to estimate 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.

One way of figuring out when you can plant delphinium is to check out the USDA zone info for Dover.

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 are one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant delphinium in Dover 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 fully mature. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

In Dover the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of 0°F.

Remember that USDA zone info for Dover is not always accurate and the actual date of last frost changes from year to year. Half of the time in Dover it frosts late in the year after April 15 so make sure that you are ready to protect your delphinium if you have a surprise late frost.

USDA Zone Info for Dover

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Dover

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