Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of figuring out when it's the best time to plant gomphrena is to check out the USDA zone info for Marshalltown.

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.

Since gomphrena are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant gomphrena in Marshalltown 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 gomphrena and expect a good harvest is probably August. You probably don't want to wait any later than that or else your gomphrena may not have a chance to fully mature. You can get started a little bit earlier by starting your gomphrena indoors.

Last Frost Date

The average date of last frost is April 15 in Marshalltown. In the coldest months of winter you can expect an average low temperature of -20°F.

Remember that USDA zone info for Marshalltown is an average and the actual date of last frost is different every year. Half of the time in Marshalltown you get surprised by a frost after April 15 so be sure to be ready to cover your gomphrena if you have a late frost.

USDA Zone Info for Marshalltown

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Marshalltown

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