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.

A way of determining when it's possible to plant lithospermum is to consult the USDA zone info for Grand Forks.

Planting Calendar for Lithospermum

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

Lithospermum require warm weather which tells us that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant lithospermum in Grand Forks 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. If you wait any later than that and your lithospermum may not have a chance to grow to maturity. Starting your lithospermum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Grand Forks is an average and the actual date of last frost will vary from year to year. Half of the time in Grand Forks last frost occurs after May 15 so always be ready to cover your lithospermum if you have a late frost.

USDA Zone Info for Grand Forks

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 Grand Forks

You may be interested in your other planting guides for Grand Forks.