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.

One way of estimating when it's possible to plant zinnia is to consult the USDA zone info for Irmo.

Planting Calendar for Zinnia

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

It's probably a bad idea to plant zinnia until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant zinnia in Irmo 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 fully mature. You can get started a few weeks earlier by starting your zinnia indoors.

Last Frost Date

In Irmo the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 10°F.

Keep in mind that USDA zone info for Irmo is just an average and the actual date of last frost is different every year. Since half of the time in Irmo it frosts late in the year after March 15 be ready to protect your zinnia if you have a surprise late frost.

USDA Zone Info for Irmo

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 Irmo

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