One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when to plant delphinium is to refer to the USDA zone info for Brookhaven.

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 just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Brookhaven 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. If you wait 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 few weeks earlier.

Last Frost Date

In Brookhaven the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Brookhaven is an average the actual date of last frost changes from year to year. Since half of the time in Brookhaven there is a last frost after April 15 be ready to cover your delphinium if you have a late frost.

USDA Zone Info for Brookhaven

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 Brookhaven

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