One of the best tools that you have as gardeners to help us determine 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.

In Union you can estimate when it's a good idea to plant zinnia by reviewing the USDA zone info.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since zinnia are not cold tolerant you have to wait until after the last frost before you can plant them.

The earliest that you can plant zinnia in Union 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. If you are starting your zinnia 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 March 15 in Union. It might get as low as 10°F during the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Union and it can change quite a bit from year to year. Half of the time in Union you get surprised by a frost after March 15 so just be sure to be ready to protect your zinnia if you have one of those late frosts.

USDA Zone Info for Union

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 Union

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