The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's the best time to plant delphinium in Hillsdale by looking at 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 can survive in some cold which means that you can plant them just a tiny bit earlier in the year than other plants that might not handle 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. If you wait any later than that and your delphinium may not have a chance to grow to maturity. Starting your delphinium indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Hillsdale. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Hillsdale is an average the actual date of last frost will vary from year to year. Half of the time in Hillsdale last frost occurs after April 15 so make sure that you are prepared to cover your delphinium if you have one of those late frosts.

USDA Zone Info for Hillsdale

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 Hillsdale

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