One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Derby you can estimate when it's possible to plant delphinium by using the USDA zone info.

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 tend to make it in mild cold which means that you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Derby 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 grow to maturity. If you are starting your delphinium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Derby. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that USDA zone info for Derby is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Derby you get surprised by a frost after April 15 so make sure that you are prepared to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Derby

Here is the info for USDA Zone 6b.

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

Plants to Grow in Derby

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