The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when to plant delphinium is to look at the USDA zone info for Prospect Park.

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 moderate cold which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant delphinium in Prospect Park 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. If you are starting your delphinium indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Prospect Park. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Prospect Park is just an average the actual date of last frost changes from year to year. Half of the time in Prospect Park you get surprised by a frost after April 15 so just be sure to be ready to protect your delphinium if you have a late frost.

USDA Zone Info for Prospect Park

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 Prospect Park

You may be interested in your other planting guides for Prospect Park.