One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. 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 Longmont can be reviewed to figure out when it's the best time to plant columbine.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since columbine are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant columbine in Longmont is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably September. You probably don't want to wait any later than that or else your columbine may not have a chance to grow to maturity. If you are starting your columbine indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Longmont. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Longmont is an average the actual date of last frost changes from year to year. Since half of the time in Longmont it frosts late in the year after April 15 be ready to cover your columbine if you have a 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.