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 iresene in Fort Collins by looking at the USDA zone info.

Planting Calendar for Iresene

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

Iresene require warm weather which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant iresene in Fort Collins 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 iresene and expect a good harvest is probably August. Any later than that and your iresene may not have a chance to grow to maturity. If you are starting your iresene indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for Fort Collins is just an average the actual date of last frost changes from year to year. Half of the time in Fort Collins you get a frost after April 15 so be sure to be ready to cover your iresene in the event of a surprise late frost.

USDA Zone Info for Fort Collins

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 Fort Collins

You may be interested in your other planting guides for Fort Collins.