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.

One way of estimating when to plant lithospermum is to refer to the USDA zone info for Rice Lake.

Planting Calendar for Lithospermum

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

Since lithospermum do not do well in cold weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum in Rice Lake 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 lithospermum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lithospermum may not have a chance to fully mature. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Rice Lake. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Rice Lake is not always accurate the actual date of last frost changes from year to year. Half of the time in Rice Lake there is a last frost after May 15 so make sure that you are ready to cover your lithospermum in the event of one of those late frosts.

USDA Zone Info for Rice Lake

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 Rice Lake

You may be interested in your other planting guides for Rice Lake.