When to Plant Iresene in Johnstown, CO

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Johnstown can be used to figure out when it's the best time to plant iresene.


Planting Calendar for Iresene

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

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

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant iresene
Possibly ok, but a risky time to plant iresene
Probably not a good time to plant iresene

The earliest that you can plant iresene in Johnstown 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. You probably don't want to wait any later than that or else 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 few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Johnstown. 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 an average because it is based on the USDA zone info for Johnstown and it changes from year to year. Since half of the time in Johnstown last frost occurs after April 15 be ready to cover your iresene in the event of one of those late frosts.

USDA Zone Info for Johnstown

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 Johnstown

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