One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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 common way of making a decision about when it's possible to plant zinnia is to use the USDA zone info for Rockwall.

Planting Calendar for Zinnia

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

Since zinnia are not cold tolerant it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant zinnia in Rockwall 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 zinnia and expect a good harvest is probably August. Any later than that and your zinnia may not have a chance to really do well. You can get started a couple of weeks earlier by starting your zinnia indoors.

Last Frost Date

In Rockwall the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Rockwall and it is different every year. Since half of the time in Rockwall last frost occurs after March 15 be ready to protect your zinnia in the event of one of those late frosts.

USDA Zone Info for Rockwall

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Rockwall

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