Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Hillsdale you can figure out when it's possible to plant delphinium by reviewing 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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Hillsdale 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. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Hillsdale. You can expect an average low temperature of 0°F in the coldest months of winter.

It's important to remember that USDA zone info for Hillsdale is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsdale there is a last frost after April 15 so be sure to be ready to cover your delphinium in the event of a late frost.

USDA Zone Info for Hillsdale

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 Hillsdale

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