One of the best tools that you have as gardeners to help us figure out 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.

By referring to the USDA zone info for Northfield it's possible to figure out when it's the best time to plant hypericum.

Planting Calendar for Hypericum

Frost tolerance for hypericum:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant hypericum a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant hypericum in Northfield is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant hypericum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hypericum may not have a chance to fully mature. If you are starting your hypericum 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 May 15 in Northfield. You can expect an average low temperature of -25°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Northfield and it changes from year to year. Since half of the time in Northfield there is a last frost after May 15 be ready to protect your hypericum in the event of a late frost.

USDA Zone Info for Northfield

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Northfield

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