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 USDA zone info for Robbins should be reviewed to determine when to plant lithospermum.

Planting Calendar for Lithospermum

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

Lithospermum require warm weather which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum in Robbins 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 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 grow to maturity. If you are starting your lithospermum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Robbins the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Robbins and it can change quite a bit from year to year. Since half of the time in Robbins there is a last frost after April 15 be ready to protect your lithospermum in the event of one of those late frosts.

USDA Zone Info for Robbins

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Robbins

You may be interested in your other planting guides for Robbins.