Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Isanti can be looked at to estimate when you can plant yarrow.

Planting Calendar for Yarrow

Frost tolerance for yarrow:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant yarrow much earlier in the year because they are very cold tolerant.

The earliest that you can plant yarrow 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 yarrow and expect a good harvest is probably August. If you wait any later than that and your yarrow may not have a chance to grow to maturity. If you are starting your yarrow indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Isanti is just an average and the actual date of last frost changes from year to year. Half of the time in Isanti last frost occurs after May 15 so always be ready to cover your yarrow if you have a surprise 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.