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

By using the USDA zone info for Herriman you will be able to determine when it's a good idea to plant zinnia.

Planting Calendar for Zinnia

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

You really shouldn't plant zinnia until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant zinnia in Herriman 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 couple of weeks earlier.

Last Frost Date

In Herriman the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 0°F.

Remember that USDA zone info for Herriman is just an average and the actual date of last frost is different every year. Half of the time in Herriman there is a last frost after April 15 so just be sure to be ready to protect your zinnia if you have a surprise late frost.

USDA Zone Info for Herriman

Here is the info for USDA Zone 7a.

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

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Herriman

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