One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of figuring out when it's a good idea to plant gomphrena is to refer to the USDA zone info for Waterloo.

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.

Gomphrena tend to make it in some cold which tells us that you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant gomphrena in Waterloo 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 grow to maturity. If you are starting your gomphrena indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Waterloo. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Waterloo may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Waterloo there is a last frost after April 15 be ready to cover your gomphrena if you have a surprise late frost.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Waterloo

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