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.

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

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 means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant delphinium in Brookfield 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 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

The average date of last frost is April 15 in Brookfield. In the coldest months of winter you can expect an average low temperature of -10°F.

It's important to remember that USDA zone info for Brookfield is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Brookfield there is a last frost after April 15 be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Brookfield

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 Brookfield

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