Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Duluth should be read to estimate when it's possible to plant trifolium.

Planting Calendar for Trifolium

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

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

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

Last Frost Date

On average the last frost has passed is on April 15 in Duluth. It might get as low as 5°F during the coldest months of winter.

It's important to remember that USDA zone info for Duluth is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Duluth there is a last frost after April 15 so make sure that you are prepared to cover your trifolium in the event of one of those late frosts.

USDA Zone Info for Duluth

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Duluth

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