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

The USDA zone info for Greenbelt should be reffered to in order to determine when 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.

You can plant delphinium slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant delphinium in Greenbelt 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 few weeks earlier by starting your delphinium indoors.

Last Frost Date

The average date of last frost is April 15 in Greenbelt. In the coldest months of winter you can expect an average low temperature of 0°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Greenbelt and it can change quite a bit from year to year. Half of the time in Greenbelt you get surprised by a frost after April 15 so just be sure to be ready to protect your delphinium in the event of one of those late frosts.

USDA Zone Info for Greenbelt

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 Greenbelt

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