The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant balsam in Boulder by looking at the USDA zone info.

Planting Calendar for Balsam

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

You can not plant balsam until after the last frost has passed because they require warm weather.

The earliest that you can plant balsam in Boulder 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 balsam and expect a good harvest is probably August. If you wait any later than that and your balsam may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your balsam indoors.

Last Frost Date

In Boulder the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Boulder may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Boulder last frost occurs after April 15 so just be sure to be ready to protect your balsam if you have a late frost.

USDA Zone Info for Boulder

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 Boulder

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