One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's possible to plant gomphrena by using the USDA zone info for Alton.

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 do ok in moderate cold.

The earliest that you can plant gomphrena in Alton 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. Any later than that and 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 few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Alton. In the coldest months of winter you should expect an average low temperature of -10°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Alton and it is different every year. Half of the time in Alton you get surprised by a frost after April 15 so be sure to be ready to cover your gomphrena in the event of one of those late frosts.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

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