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.

The best time to plant helianthemum in Winthrop Harbor should be estimated by checking out the USDA zone info.

Planting Calendar for Helianthemum

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

Since helianthemum do well in moderate cold you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Winthrop Harbor is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your helianthemum may not have a chance to fully mature. Starting your helianthemum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Winthrop Harbor. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Winthrop Harbor is just an average the actual date of last frost will vary from year to year. Since half of the time in Winthrop Harbor last frost occurs after April 15 be ready to cover your helianthemum if you have a late frost.

USDA Zone Info for Winthrop Harbor

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Winthrop Harbor

You may be interested in your other planting guides for Winthrop Harbor.