One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when it's the best time to plant delphinium by looking at the USDA zone info for Zone 7a.

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 one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant delphinium in Zone 7a 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. You can get started a few weeks earlier by starting your delphinium indoors.

Last Frost Date

In Zone 7a the average date of last frost happens on April 15. It might get as low as 0°F during the coldest months of winter.

Always keep in mind that USDA zone info for Zone 7a is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Zone 7a last frost occurs after April 15 be ready to protect your delphinium if you have a surprise late frost.

USDA Zone Info for Zone 7a

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 Zone 7a

You may be interested in your other planting guides for Zone 7a.