One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when to plant pyrethrum by looking at the USDA zone info for Isanti.

Planting Calendar for Pyrethrum

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

Pyrethrum are moderately cold tolerant which tells us that you can start planting them earlier than plants that are more sensitive to the cold.

The earliest that you can plant pyrethrum 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 pyrethrum and expect a good harvest is probably August. If you wait any later than that and your pyrethrum may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your pyrethrum indoors.

Last Frost Date

The average date of last frost is May 15 in Isanti. It might get as low as -30°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Isanti and it can change quite a bit 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 pyrethrum 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.