The USDA Zone info is a great tool for gardeners to help us estimate your gardening 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 Zone 4b should be reviewed to estimate when it's the best time to plant gomphrena.

Planting Calendar for Gomphrena

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

You can plant gomphrena 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 gomphrena in Zone 4b 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 gomphrena and expect a good harvest is probably August. If you wait any later than that and your gomphrena may not have a chance to fully mature. If you are starting your gomphrena indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4b. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Zone 4b may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Zone 4b you get surprised by a frost after May 15 so make sure that you are ready to protect your gomphrena if you have a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.