Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's a good idea to plant streptocarpella by referring to the USDA zone info for Boulder.

Planting Calendar for Streptocarpella

Frost tolerance for streptocarpella:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Streptocarpella are not cold tolerant which tells us that you have to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant streptocarpella 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 streptocarpella and expect a good harvest is probably August. Any later than that and your streptocarpella may not have a chance to really do well. Starting your streptocarpella indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Boulder. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Boulder may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Boulder it frosts late in the year after April 15 be ready to protect your streptocarpella 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.