One of the first steps you take when you are getting a good idea 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.

A way of determining when it's a good idea to plant coleus is to use the USDA zone info for Boulder.

Planting Calendar for Coleus

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

You really shouldn't plant coleus until after all chance of frost has passed because they require warm weather.

The earliest that you can plant coleus 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 coleus and expect a good harvest is probably August. If you wait any later than that and your coleus may not have a chance to really do well. Starting your coleus indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Boulder. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Boulder and it is different every year. Since half of the time in Boulder you get a frost after April 15 be ready to cover your coleus in the event of one of those late frosts.

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.