One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Isanti you can estimate when it's a good idea to plant heliotrope by looking at the USDA zone info.

Planting Calendar for Heliotrope

Frost tolerance for heliotrope:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You can not plant heliotrope until after the last frost has passed because they require warm weather.

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

The last month that you can plant heliotrope and expect a good harvest is probably August. Any later than that and your heliotrope may not have a chance to fully mature. If you are starting your heliotrope indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Isanti is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Isanti you get a frost after May 15 so just be sure to be ready to protect your heliotrope in the event of one of those late frosts.

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.