One of the first steps you take when you are getting a good idea 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.

One way of estimating when it's possible to plant delphinium is to examine the USDA zone info for Waterbury.

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 are barely cold tolerant which tells us that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant delphinium in Waterbury 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 really do well. If you are starting your delphinium indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Waterbury the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Just be sure to remember that USDA zone info for Waterbury is just an average and the actual date of last frost will vary from year to year. Since half of the time in Waterbury you get surprised by a frost after April 15 be ready to cover your delphinium in the event of a late frost.

USDA Zone Info for Waterbury

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Waterbury

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