When to Plant Geranium in Longmont, CO

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Longmont you can figure out when it's a good idea to plant geranium by referring to the USDA zone info.


Planting Calendar for Geranium

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

You really shouldn't plant geranium until after the last frost because they do not do well in cold weather.

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

The earliest that you can plant geranium in Longmont 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 geranium and expect a good harvest is probably August. Any later than that and your geranium may not have a chance to really do well. You can get started a couple of weeks earlier by starting your geranium indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Longmont. In the coldest months of winter you should expect an average low temperature of -15°F.

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

USDA Zone Info for Longmont

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 Longmont

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