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.

The best time to plant streptocarpella in Zone 4a should be estimated by reviewing the USDA zone info.

Planting Calendar for Streptocarpella

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

Since streptocarpella are not cold tolerant you really should wait until after the last frost has passed before you can plant them.

The earliest that you can plant streptocarpella in Zone 4a is May. However, you really should wait until June 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. You probably don't want to wait any later than that or else your streptocarpella may not have a chance to really do well. You can get started a little bit earlier by starting your streptocarpella indoors.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. You can expect an average low temperature of -30°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 4a and it changes from year to year. Since half of the time in Zone 4a last frost occurs after May 15 be ready to cover your streptocarpella in the event of a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.