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.

You can figure out when it's a good idea to plant zinnia in Arvada by using the USDA zone info.

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 are not cold tolerant.

The earliest that you can plant zinnia in Arvada 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 little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Arvada. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Arvada is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Arvada it frosts late in the year after April 15 be ready to cover your zinnia in the event of a surprise late frost.

USDA Zone Info for Arvada

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Arvada

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