The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Iron Mountain you can estimate when it's the best time to plant platycodon by looking at the USDA zone info.

Planting Calendar for Platycodon

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

You can plant platycodon a bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant platycodon in Iron Mountain is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant platycodon and expect a good harvest is probably August. You probably don't want to wait any later than that or else your platycodon may not have a chance to really do well. Starting your platycodon indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Iron Mountain may not be accurate from year to year and the actual date of last frost will vary from year to year. Half of the time in Iron Mountain it frosts late in the year after May 15 so make sure that you are prepared to cover your platycodon in the event of a late frost.

USDA Zone Info for Iron Mountain

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 Iron Mountain

You may be interested in your other planting guides for Iron Mountain.