Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Colorado Springs you should be able to figure out when it's the best time 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.

It's a bad idea to plant zinnia until after the last frost because they are not cold tolerant.

The earliest that you can plant zinnia in Colorado Springs 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 grow to maturity. Starting your zinnia indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Colorado Springs. You should expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Colorado Springs and it can change quite a bit from year to year. Since half of the time in Colorado Springs last frost occurs after April 15 be ready to protect your zinnia in the event of a surprise late frost.

USDA Zone Info for Colorado Springs

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Colorado Springs

You may be interested in your other planting guides for Colorado Springs.