One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

In Boulder you can estimate when you can plant stevia by reviewing the USDA zone info.

Planting Calendar for Stevia

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

Since stevia do not do well in cold weather you really should wait until after the last frost before you can plant them.

The earliest that you can plant stevia 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 stevia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your stevia may not have a chance to fully mature. Starting your stevia indoors is a great way to get them started a couple of 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 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 always be ready to protect your stevia if you have 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.