One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

A common way of getting a good idea when you can 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 do ok in some cold which means that you can plant them slightly earlier in the year than more sensitive 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 grow to maturity. You can get started a few weeks earlier by starting your delphinium indoors.

Last Frost Date

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

Since the USDA zone info for Brookfield is just an average the actual date of last frost will vary from year to year. Half of the time in Brookfield you get a frost after April 15 so make sure that you are prepared to protect your delphinium if you have a late frost.

USDA Zone Info for Brookfield

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Brookfield

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