The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to determine when you can plant helianthemum by reviewing the USDA zone info for Isanti.

Planting Calendar for Helianthemum

Frost tolerance for helianthemum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since helianthemum are moderately cold tolerant you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Isanti 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 helianthemum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your helianthemum may not have a chance to fully mature. You can get started a few weeks earlier by starting your helianthemum indoors.

Last Frost Date

The average date of last frost is May 15 in Isanti. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Isanti is just an average the actual date of last frost changes from year to year. Since half of the time in Isanti you get surprised by a frost after May 15 be ready to cover your helianthemum in the event of a late frost.

USDA Zone Info for Isanti

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Isanti

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