One of the first steps you take when you are determining 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.

You can estimate when it's a good idea to plant alternanthera in Petersburg by referring to the USDA zone info.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After the last frost.

Alternanthera do not do well in cold weather which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant alternanthera in Petersburg 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 alternanthera and expect a good harvest is probably August. You probably don't want to wait any later than that or else your alternanthera may not have a chance to fully mature. Starting your alternanthera indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Petersburg. In the coldest months of winter you can expect an average low temperature of 5°F.

Since the USDA zone info for Petersburg is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Petersburg there is a last frost after April 15 so make sure that you are ready to cover your alternanthera in the event of a surprise late frost.

USDA Zone Info for Petersburg

Here is the info for USDA Zone 7b.

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

Plants to Grow in Petersburg

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