One of the first steps you take when you are getting a good idea 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.

In Harrison you can determine when it's a good idea to plant zinnia by referring to the USDA zone info.

Planting Calendar for Zinnia

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

It's probably a bad idea to plant zinnia until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant zinnia in Harrison 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. If you wait any later than that and your zinnia may not have a chance to fully mature. 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 Harrison the average date of last frost happens on April 15. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Harrison is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Harrison you get surprised by a frost after April 15 be ready to cover your zinnia in the event of one of those late frosts.

USDA Zone Info for Harrison

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 Harrison

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